NTX5467

The "T-" number is the identification number of a particular "special tool" for that operation. GM's special tools were made by Kent-Moore, but that company's now called SPX. That special tool can be ordered from them, if you desire. The "T-" number will not cross into anyone else's tool numbers or be listed as such in the other tool catalogs. Snap-On, Matco, and others might have similar tools as that particular SPX tool, but you have know how to contact those tool companies' local represtatives to get one, if they have one.<P>Clymer auto manuals typically will detail what more common tools to use to take the place of the particular factory special tools. I'm not sure if they will do that in your case.<P>"Allen wrenches"? They've been around for ages. They are used with a bolt head that has an internal hex (recessed) and a round outer "head" surface, instead of the more traditional outer hex surface and flat head. Then there are also "torx" head bolts/studs (probably what is on your vehicle, as they look similar to allen bolts/studs but are more star shaped with sharp points).<P>This could well be a situation where that repair might be best given to those who "have been there before" . . .<P>Enjoy!<BR>NTX5467

"Breather tube" as in from the air cleaner to the valve cover for the crankcase ventilation system? Or the "breather tube" for the hot air from the exhaust manifold heat stove to the bottom of one of the air cleaner snorkles?<P>In either case, these would have been dealer only items, especially if the hot air tube was formed metal tubing instead of the flexible tubing of later years.<P>If you can find a GM part number for the desired tube, you might try <A HREF="http://www.partsvoice.com" TARGET=_blank>www.partsvoice.com</A> or some of the restoration/NOS parts vendors.<P>NTX5467

I suspect that "hum" will be aided by the particular sounds of the Buick straight 8 engine mated to a DynaFlow--especially on "takeoff". Plus the exhaust note of the nailhead V-8s. Such neat sounds to those who appreciate such things.<P>Monica can make her own particular noises . . .<P>Enjoy!<BR>NTX5467

Thanks for posting that article here, Roberta!<P>NTX5467

With all due respect, it sounds like that striker would not have bent or deformed the lock pillar if the hinge pin bushings had been replaced sooner. That piece of lock pillar is a separate stamping that is welded in just as any other body panel's welded in. It's not the easiest or cheapest body shop operation to do, but it's doable. Even on the newer models with the one piece complete door frame stampings, there are procedures to section them to replace parts of them without having to replace the entire stamping.<P>Those '80s cars were designed prior to the federal side impact safety tests. I can tell you from my own experience and observations, the newer cars that were designed for these current standards are much better than the prior ones--no doubt about that.<P>The door hinges on the '70s and earlier cars were of a more substantial and complex design than the current ones. I also suspect the cowl area and door shells were more substantial in design too. They were also designed to support more weight in the process. Usually if the bushings wore, you could tweak the hinge adjustment a little to compensate for it. But I have yet to find a '70s GM hardtop or convertible (the models that had quarter windows beside the rear seat) that did not have some deflection in the lock pillar area when the door was closed--another observation.<P>There are plusses and minuses for both the older and current/future construction strategies. Each has their merits and lesser accomplishments when compared to each other. Some of the newer designs certainly might look flimsier than the earlier ones, but the energy dissipation from the crash forces is a more evolved science than in previous times. Plusses and minuses there too with respect to repairability and similar concerns. <P>Just as there are some areas of the first generation F-body (Camaro/Firebird) that are better than the second generation and there are areas of the second, third, and later generations that are better than the first generations (especially body stiffness).<P>I wasn't aware that GM was using the foam fillings in any of their earlier vehicles. Not that they didn't for a structural reinforcement fix or a noise concern. I know that Chrysler issued a service bulletin on noise concerns (earlier production LH cars) that involved adding the foam in the door/cowl areas. The current Park Avenue has those things too.<P>Just some additional thoughts . . . .<P>NTX5467

When I made the post last night, I was thinking that your vehicles were the next and last generation of Rivieras, hence the reference to superchargers.<P>I did check the GM parts database and discovered that all of the rear struts for the 91-93 Rivs are the same. The fronts for the 90-91 Rivs are the same, but the 93 uses a right and left strut instead. The upper strut mounts on the front are the same part, but there must be some bracket or something attached to the struts that makes them side specific in the later years. There was only one part number for the front struts--no "RSS" option listed, but I didn't check the 94s.<P>In order to track that situation, it would be necessary to find some factory literature to confirm it. GM has ceased to support the electronic struts on the Allantes and issued a service bulletin of how to retrofit the non-electronic struts and keep the computer from knowing what was happening. If there was such an option on the Rivs, it would have probably received a similar fate, but I don't recall the bulletin applying to anything other than the Cadillac Allante/Eldorado vehicles. In any event, if your car had that, there would be some wires going directly into the strut itself plus a small lever going between a motion sensor at each wheel and the lower control arm.<P>There were standard suspensions and upgrade suspensions. The difference between them is the springs and sway bars as the struts are common items between them.<P>If done correctly, the firmer suspension calibration will be firm but not harsh. On rough roads the car will be more stable and feel like it is "above it all", so to speak, but without really floating or feeling mushy as the softer suspensions might be.<P>I also checked the price on the rear suspension height sensor -- $369.00 retail. A good troubleshooting session might be in order. I suspect the more specific GM factory service manual might be better than the Chilton in many situations. The Chilton, Clymer, and Motor manuals are good, but are more generalized in nature and could miss some year specific items in the process, especially in illustrations. <P>Enjoy!<BR>NTX5467

I highly suspect that if the later model Riv rides firmer than the earlier one, it would be due to different suspension calibrations and different suspension codes (i.e., FE1 for the base suspension and FE2 or FE3 for the firmer one). You can find those codes on the Service Parts Identification Label that usually is on the top of the spare tire cover. <P>I do not recall any Rivieras having electronic struts and "road sensing" as the Cadillacs did or do. What Monroe calls "road sensing" in their shocks/struts is NOT the same thing as electronic struts as Cadillac and Corvette uses that are controlled by the body module computer from wheel sensor inputs or calibration mode switches. <P>By that point in time, if any suspension upgrades were done, it was not with the struts but with stiffer springs, larger sway bars, and performance oriented tires (with stiffer treads and sidewalls). When you add in the performance nature of the 16" tire package you have, "float" will be decreased as less movement is filtered out by the performance-oriented tires. I would suspect that if the later Riv is supercharged and the earlier one is not (as the smaller 15" tire size would tend to indicate), that could be the reason for the suspension being calibrated differently.<P>When the automatic leveling kicks in, it should only raise the vehicle to the original ride height, not higher. There is a height sensor in the rear suspension to control that issue. In any event, in it's "curb ride height" with no one in the car, the rocker panel should be basically level, but many newer vehicles are configured such that the rear is slightly higher than the front when unloaded. I seem to remember those Rivs being a little higher in the rear when empty.<P>I seem to remember that the earlier version of those Rivieras could be had with a "base" car (i.e., base 3800 V-6 of about 200 horsepower, normal 15" wheels and tires, softer springs and sway bars) or with the optional supercharged 3800 and appropriate suspension upgrades (all with automatic leveling). In the later years, it seems the supercharged 3800 became standard and would probably have also included the suspension upgrades as standard too. They all sat higher in the back such that the rocker panel tilted upward toward the rear end of the car.<P>As far as I know, all of the pieces of the automatic leveling suspension are going to be dealer only items. The rear struts can be obtained from aftermarket sources, though, just as shock absorbers would, but will need to have the correct fittings for the factory air lines on them. If the automatic leveling is not desired, you can unplug the compressor for the system. But, it sounds like the system is operating as it should and just needs a check of the height sensor at the back.<P>Just some thoughts . . .<P>NTX5467

For what it's worth, the stated spec on Chevrolet V-8s for lifter adjustment is something like 2 turns preload after zero lash. This is supposed to basically center the lifter piston in its available travel in the lifter body.<P>Most of the hot rodders only put about 1/4 turn preload on them for more rpm as at higher rpm, the lifters can pump up (i.e., the lifter's internal piston will be pushed higher in its bore with higher oil pressure) and not allow the valve to seat at those higher rpms, hence the reason for less preload. This is an old hot rod trick from way back for the Chevy V-8s to get the engines to rev higher.<P>From my own experiences, I like 1/2 turn preload rather than 1/4 turn preload so you don't have to go back and do it again later. The whole idea is to get the slack (i.e., "lash") out of the valve train so it's quiet and stays that way.<P>As you bought an aftermarket cam and lifter set, I would suspect there should be some recommended adjustment setting in the instructions. Using a stock adjustment for an aftermarket high performance hydraulic lifter might not be optimum as their lifters might have a different size oil bleed hole or other features to keep them from pumping up at high rpm. <P>In one respect, as long as there is enough preload to keep the hydraulic lifter valve train at "zero lash" at all times and operational temperatures, that's all that is really needed, but some preload will be necessary to keep the piston from constantly being against the snap ring that keeps it inside the lifter body. In the absence of any recommendations from the cam/lifter manufacturer/vendor, you might experiment some.<P>If you adjust the lifters with the engine running, you can try some of the "stoppers" that might be put on the ends of the rocker arms to decrease the amount of oil splashing around. Plus some cardboard to hopefully keep some of the runoff from getting on the exhaust manifolds and inner fenders. Otherwise, be sure to have some of your favorite engine degreased on hand. Setting the preload with the engine running is the best way to do that adjustment, just don't force the preload on the lifter too fast.<P>Enjoy!<BR>NTX5467

Most of those problems on the Cierra should have been easy fixes. <P>The headliner issue is a normal one as the foam backing deteriorates with age. Certainly not specific to GM at all. Only repair is to either pull it all down or get it replaced. The trim shop people advised to NOT try to reglue it as it only made cleaning the backing board more difficult when it was prepped for new fabric.<P>The door hinges probably just needed new hinge pin bushings to put them back right, maybe some new pins too--more labor intensive than parts price intensive, for sure. Probably a new striker bolt too as the lock probably had rubbed a flat spot on the top of it. <P>Many people unconsciously press down on a door when they open it, even if you walk up to a door in a building with a cross bar, it seems to be instinct to push downward before you push forward. Same with car doors, it seems as people push down with their elbows and forearms before they push outward when they get out of the car. Something I observed even myself to do before I conditioned myself not to. That downward push puts additional wear forces on the bronze hinge pin bushings over a period of time. In earlier times with the older design latches, the doors popped outward when you pulled the handle to open them, but the newer design latches don't seem to do that. We stock the bushings and pins for late model GM pickups by the handfull as them wearing out is a "normal wear item" on those vehicles.<P>I suspect the steering column was what I call "The Thunderbird Syndrome" where the wheel can be moved around in the column. Four long screws in the lower part of the column (below the tilt wheel pivot) get loose and the pot metal casting they go through can break as the tilt wheel is let "pop" up unrestrained as you pull the tilt lever when you get out of the car. The people who advertise to fix GM steering columns or a dealer with the correct part can probably have it fixed in an hour or so.<P>All of those things are "typical" issues with age that are sometimes more troublesome to tolerate than fix. Not a lot of money involved either. These are things I've observed in the dealership parts area during the past 25+ years so they aren't "big deals" to me to see these things happen, but others might not feel that way.<P>The windshield header rust is certainly unusual, though. Must have been moisture getting trapped up there for some reason. I don't think they fully dipped those bodies in the rust inhibitor tank back then.<P>I concur that the mechanicals usually caused no problems at all. I suspect these were better cars than many people ever gave them credit for being in that respect.<P>Enjoy!<BR>NTX5467

If you've got a vehicle with a windshield that uses a gasket, then you probably need to check with vendors for that particular type of vehicle for help finding one. Steele probably has some "roll goods" that might be acceptable, but you probably have a gasket that has molded corners and such too, making such roll goods (sold by the foot) unacceptable.<P>Steele is a main manufacturer for many things, even things that other people sell under their own name, but I suspect you'll need to find vendors which specialize in that year and model of vehicle to get what you need.<P>It could be that a glass company that is used to doing older vehicles might not arbitrarily require new gaskets with all installations. It is a good orientation, though, as the previous gasket has taken a set to the glass in it (especially with respect to glass thickness). Plus, the rubber might not flex and tolerate the movement of the glass being taken out and reinstalled.<P>Hope this helps,<BR>NTX5467

If that car is what I think it is, it would be the precursor to the later T-Type models in basic suspension calibrations. There was nothing special in the engine department, but the body color trim and other "sporty" cosmetics made it work. The chassis upgrades were nice too. <P>There were some Olds Cierra GTs too, as mentioned, but one of those Centurys in solid black looked really good.<P>Collectibility? I'd consider that a tossup right now, but as more of the younger generation that grew up with fwd cars comes to appreciate these special, lower production Buicks, it could be a "keeper" for sure. Just like the later fwd T-Type LeSabre coupes. I suspect there were more of the Centurys than Cierra GTs, from what I remember.<P>Sounds like a neat car that deserves to be treated with care and respect--even if it spins the "wrong set of wheels". Afterall, it's a Buick too.<P>Enjoy!<BR>NTX5467

Those cars seem to hold up well. There were also some Olds Toronado convertibles in the mix too.<P>I believe the conversions were done by what was then American Sunroof Corporation. <P>Enjoy!<BR>NTX5467

For the type of "high mounted stop light" you describe, you might check with some of the street rod parts vendors. I believe I've seen just what you need in their magazine adds.<P>The factory GM Accessory HMSL kits used a relay to run them instead of tapping directly into the stop light circuit. It had it's own particular harness and everything. This kept it isolated from the main brake light operation too.<P>I bet you'll find what you need with the street rod parts vendors, though.<P>Enjoy!<BR>NTX5467

The fuel pressure and fuel filter issues are both valid points. A minimum fuel pressure is necessary for the injectors to do their job. If, during cranking, the pressure starts out low and then builds, the injectors will fire only when the pressure builds to the minimum pressure they need--and not before. <P>If the fuel filter is clogged or restricted, it can delay the pressure building immediately in the fuel rail. After the vehicle sits and previously pressurized fuel gets through the filter, they usually start the second time. There also is a pressure regulator on the fuel rail near the connection for the fuel pressure gauge. In any event, the pressures need to be "in spec."<P>We recently had a later model Chevy pickup in the shop for a problem similar to what you mention, plus a "low power" complaint. With the fuel pressure gauge hooked up, during the cranking to start, the pressure started out at about 45psi and slowly built to 55psi before the engine started. Once started, the fuel pressure acted normally, but dropped back too far under acceleration.<P>We recommend fuel filter changes every 30,000 miles on fuel injected GM vehicles. When the filter becomes clogged, it causes the fuel pump to draw too much current and can melt the wires in the sending unit/fuel pump module--not inexpensive items to replace. Fuel filters are much easier and cheaper to replace.<P>NTX5467

The poor reception (and hiss from the amp due to poor signal input) sounds like an antenna lead-in problem. The cable might look good, but could have internal problems. If it's a two piece lead-in (i.e., with a joint somewhere in the assembled length), there could be a problem there or with the lead-in itself near the antenna. We had problems with water getting inside the coax on some '88 vintage Chevy pickups on the outer length of the coax. <P>If the drain on your electric antenna is plugged (I suspect it has an electric antenna), it could possibly cause a water problem that way. In any event, I suspect you will need to replace the full length of coax lead-in to fully address the problem (poor reception). Maybe even the power antenna.<P>Generally, the condensor on or in the alternator circuit is for "whine" that varies with engine rpm.<P>Enjoy!<BR>NTX5467

The 260 V-8 back then was purely an Olds engine, a smaller version of the 307/350 line. There were some issues with the intake manifolds leaking, but at this time, I suspect an aftermarket manifold or a repair (aluminum welding and reshaping) might be appropriate (the aftermarket intake will need a carb adapter, probably). I never did understand why those intakes were so expensive, but their problems might have been due to maintenance issues too.<P>Chevy built a 262 V-8 earlier on that was unique in that it had different main bearing sizes (smaller) than any other small block Chevy V-8. It typically went in Monzas back then. The CA spec Monzas got 350s for some reason with the 305 replacing the 262 in later years. <P>In the later '80s, there was a Chevy 267 V-8 that was like a smaller 305 and had common internals. The 267 also had throttle body fuel injection when in the Caprices.<P>Naturally, the 231 Buick was probably the best way to go (and I suspect all of the frame rails would accept ALL of the engine variations), but production and marketing issues dictated that a Chevy have a Chevy motor and similar with the other lines too--especially Olds.<P>In the later '70s, Pontiac also had their own 260-something V-8, that was part of the same family as the 301. Those engines were designed strictly for light weight and fuel economy. The turbo 301 blocks had extra reinforcement, but they later were the only block used on the 301s as time progressed.<P>Not to be left out, Cadillac had their HT4100 V-8. "HT" meaning "High Torque". This was the same engine that was available in their large DeVilles, etc. with the 4.1L Buick V-6 available optionally. The HT4100 Cadillac V-8 later was used in the fwd DeVilles and such, growing to 4.5L and then 4.9L in later years. The earlier HT4100s did have their problems, but by the time the 4.5L came around, they were basically fixed. Many 4.5Ls and 4.9Ls were used to replace HT4100s in later years--a bolt in power swap.<P>The 4.lL Buick V-6 also saw use in the fwd Centurys. The reason the front end on those cars was longer was due to the wider width of the 90 degree Buick V-6 instead of the 60 degree Chevy 2.8L V-6 used in other applications on that platform.<P>Back then, the issues were weight and fuel economy instead of power. Look how much more power and fuel economy we have now from the same basic size engines--at higher equipment and repair costs too.<P>Hope this clears up some of the confusion on engine sizes and manufacturing divisions back then.<P>Enjoy!<BR>NTX5467

Stretching and retempering coil springs is similar to rearching leaf springs. Remember that all you are trying to do is put things back like they were originally. Just as with leaf springs, the spring shop should know how much to stretch to get the desired "free" length when done. Retempering would be the key operation here, it would seem.<P>The reason the spring compressed was due to use. When the correct free length is achieved and the spring is retempered, it should be the same as when new--if done correctly. Same ride stiffness and all. Generally, the farther apart the coils are, the higher the spring rate, but as you are only trying to reestablish the original condition, those comments about "stiffness" would not really apply, unless the retempering process made the spring metal harder or something.<P>The other key item in that process will be the person doing it. If, in the stretching process, they break the spring, you'll basically end up buying new springs anyway. Unlike with leaf springs where there is a basic curve they work to achieve, the coil spring deal would be totally trial and error to get the right free length. I suspect that some spring shops (that normally deal with leaf springs in the reconditioning operations) might not have the proper equipment to do coil springs, or have the liability insurance to cover that. In any event, the end product will only be a good as the person doing it, I suspect.<P>I concur that there will be more truck spring operations than what you will find for cars. Same principles, just different items. We used to use a HD truck spring shop for our dealership light truck spring repairs. In the earlier times, they heated the leaves before they rearched them. In later years, they did it by using a cold press operation. Personally, the kiln operation seems like it would be the best way.<P>In one respect, reconditioning the spring is what I'd consider a last resort "fix". If a new spring of the correct application can be found, then that would be the best way to go.<P>Just some thoughts . . .<P>NTX5467

The way that replacement springs were determined (in the "Computer Selected Spring" era of GM) was with a chart in the GM Parts Manual. You started with the basic model, then went to the appropriate front spring or rear spring chart. Then you added to the basic weight capacity from the list of optional equipment to arrive at the weight each wheel would have to support. There were charts for the standard suspension and also for the upgrade "performance" (usually F41) suspension option (when offered) too. <P>Once you had the total weight figure, you went to another chart with the part numbers for particular weight ranges. That's where you found the GM part number you needed.<P>In the later '70s, you used the GVWF/GVWR rating on the door decal. At that time, the weights was in "kg" instead of "pounds". Same scenario though, you went to the chart where the weight ranges and the part numbers were.<P>GM never did release the "lbs/inch" deflection rating in their parts number specs. You'd probably have to get the SAE specs that were filed each year for that figure. "Car Life" magazine used to publish them, but they were absorbed by "Motor Trend" by the time your Riviera was built.<P>TRW, Moog, and other suppliers do have all of the spring specs in the back of their coil spring catalogs. Quite an interesting list, especially when you look at what certain springs fit other than their original application. <P>Eaton/Detroit Spring is a GM Restoration Parts vendor so, if you can determine the correct GM part number you need (from the GM Parts Manual, as described) they can supply it. The GM Restoration Parts Catalog has a long list of spring part numbers in it, but applications are not listed. Eaton/Detroit Spring claims to have blueprints of OEM springs back to whenever. I suspect that what they would supply would be as close as you will come to the factory correct spec items. I believe they also have a website for inquiries. The springs from the other aftermarket suppliers will be more general in application than what GM specified.<P>Enjoy!<BR>NTX5467

Check with Sherman and Associates for the patch panels. <A HREF="http://www.shermanparts.com" TARGET=_blank>www.shermanparts.com</A> They have pretty much anything that is available and probably build most of what everyone else sells. Check it out.<P>NTX5467

A build sheet can be neat documentation, but it's not necessary documentation. The additional copies stuffed into the back of the seat springs and such helped make sure the right seats got in the correct vehicle, but if two vehicles had the same interior, the line worker might not grab the correct (according to the build sheet) seats for the vehicle. I suspect there should be one sheet for the front seat and the back seat. I never did understand the gas tank location though. I have seen pictures of (what I did not know at that time) build sheets taped to the cowl of the car before the fenders went on. Having it on the basic body shell prevented the line workers from having to look at the trim (i.e., body) plate on the cowl, I suppose, and expedited them doing their job.<P>From what I've seen in the front of the old Chevy parts book, there was a lot of information stamped onto the old warranty plates that came with the vehicles and were supposed to be correctly mated with their respective vehicle. I guess that if the car came with a Holley carb and the warranty repair parts were for a Rochester, that might make them deny the claim for "incorrect parts" if they could look at the imprint of the warranty plate and see that as they processed the claim at the zone office.<P>As far as the major items, you can get that off of the body plate on the cowl (without twisting any wrenches). It might be possible to decipher the engine from the VIN and further inspection of the vehicle could determine if the engine, trans, rear axle are correct for that particular year and model of vehicle (by the stamping codes). The build sheet, naturally, would nail down all of the questionable variables if you knew how to read and understand it (from the codes and such). It's not nearly as neat and easy to document those earlier GM cars as it is the similar Chrylser products.<P>At this point in time, "numbers match" for an earlier vehicle is a neat thing to have, but it's not necessary considering how many component failures could have resulted over the years. What should matter is how things fit together as they are or could have been when the vehicle was new (i.e., option packages, colors, trim). I suspect that if you're trying to document a genuine GSX over a regular GS or Skylark, for example, the time you spend might not be justified. In other words, it would be nice to find the build sheet but it's not totally necessary.<P>You could spend your time better by getting appropriate sales literature or even the Dealer Order Guide for that year and model. There are also some other publications out there that might help find what you're looking for.<P>Enjoy!<BR>NTX5467

I checked the GM Parts database at work. What I found was a seeming hodge-podge of varied availability of the M20 4-speed manual transmission in the A-body '78-'80 models. I'm not sure how what vehicles in what years would use that transmission, but it was varied. For example, Buick had it in '78 but not '79 (as I tried to chase the ID codes in the year model charts and then the applications in the parts area). Chevy, Olds and Pontiac used it in varied years also. In all cases, the engine applications listed were for the Buick 231 V-6, Chevy 267 V-8, and the Olds 260 V-8.<P>What I found (that I'd forgotten about) was the option code M75 5-speed manual transmission. It was listed for the Buick and Olds engines (listed above) only. I suspect this is the same transmission that was used in the Skyhawk, Firenza, Monza (i.e., later version Vega) cars also as its first year was about 1976 and used through about 1981.<P>The other interesting thing I found in the engine/transmission code chart was for the GM X-cars. How about a 4-speed manual transmission Buick Apollo? Probably similar with the Nova and Omega too.<P>Sometimes, when doing these "unusual" searches, you have to look for related items in addition to the main item. In this case, transmission shifters were a related item.<P>I did not find the listings for the 4-speed manual trans Malibus with a 305, though, for some reason. I recall at the time it was in the GM order guide as being available and even saw a number produced in print (probably in Super Chevy magazine).<P>In any event, the reason for these unusual trans/small engine combinations was fuel economy more than anything. I seriously doubt that the M75 would take the power of a larger V-8 engine or probably a racing situation. Combined with the F41 suspension, the manual transmission could transform an otherwise dull vehicle into one that was fun to drive in something other than a straight line.<P>Enjoy!<BR>NTX5467

I suspect there's a misprint there somewhere. The only 4-speed manual transmissions in the A/G body series back then, as far as I know, were behind the Chevy 305s in Malibus--and they certainly were not standard nor many of them built. <P>Seems like the Turbo 200R4 overdrive (4-speed) automatics came in the later 1970s or early 1980s and the Turbo 700 overdrive automatic came out in the early 1980s. I'm not at work so I'm remembering how things seem to have been. We had the Turbo 200s and 350s with lock-up torque converters before the overdrive automatics came out.<P>Also remember that those brochures are finalized and printed in about July before the new models come out in the Fall. It could have been that Buick was supposed to intially get a 4-speed automatic at the time the brochures went to print, but it didn't happen, in which case stickers should have been sent with the catalogs noting the changes. Later versions would have the more correct information. As the fine print notes, "Specifications subject to change without notice".<P>My gut suspicion is that it's just a typo that missed the proof read operation. I certainly don't recall seeing any transmission with 4 forward speeds in the Buick or GM parts catalogs back then, except for the V-8 Malibus (but there could have been some Pontiacs too, all things considered) I mentioned above.<P>Just some thoughts . . .<BR>NTX5467

GM claims that their current DexronIII fluid is backward compatible all the way back to 1949 in their transmissions. The orig Dexron fluid replaced Type A when it came out in the later 1960s. The current DexronIII is the latest variation of that orig Dexron fluid.<P>I highly suspect that DexronIII is highly superior in its additive packages and such than the earlier Type A fluid. My recommendation would be the DexronIII fluid, but others might prefer the earlier Type A spec fluid if it's still around.<P>Enjoy!<BR>NTX5467

If the fan clutch is working correctly, it should freewheel as vehicle speed increases. If you got a fan clutch that is smooth on the front, it will kick out only with rotational rpm as there is no thermostatic spring to help it come in as needed. The factory OEM clutches will have the thermostatic spring on the front that are heat sensitive. They will still spin with the water pump, but will tighten up as the heat coming through the radiator gets above their design "activation" point. <P>In the summer, we used to get some customers come in with their 454 C30s complaining of a transmission problem while towing. They thought it was downshifting or slipping due to the fan noise. What it was was the fan clutch cycling in and out as needed and not the transmission.<P>Just some additional thoughts . . <BR>NTX5467

Correct, the 1973 and earlier Imperials were on a stretched version of the Chrysler C-body platform, having about a 127" or so wheelbase instead of the normal 124" wheelbase as the other Chryslers did. Prior to the 1967 version (when the Imperials became a longer wheelbase version of the Chrysler C-body platform), they had their own unique body/frame construction car on a 129" wheelbase. About the only thing that carried over was the engine and transmission with the other Chryslers, from what I could tell.<P>The new for 1974 C-body platform had the Imperial and Chrysler on the same wheelbase for the first time. The Imperial, naturally, had fancier and different interior trim and the waterfall grille while the other Chryslers had more traditional grilles and such. When the Imperial was discontinued on that platform, the same car became the 1976 Chrysler New Yorker Brougham.<P>One significant difference in the 1974 style Imperials and the regular Chryslers was the availability of 4 wheel disc brakes with optional "4 wheel anti-lock". The rear disc brakes were standard equipment, but the anti-lock was optional. It was an advanced system (for the time) with two levels of brake pressure in the apply/release cycle instead of being just for the rear wheels and either "on" or "off" as Ford and GM did with their anti-lock systems. It was a low sales item and died with the last of those Imperials. Being a 4 wheel anti-lock system, it allowed the driver to steer and stop just as with the current systems instead of just being concerned with the rear wheels locking up.<P>Enjoy!<BR>NTX5467