Desolow52 Posted March 11, 2009 Share Posted March 11, 2009 I just picked up a '61 Olds 98 4 dr HT with a 394 and a bad tranny. Does anyone know what years/other GM makes are interchangeable? Can I easily upgrade to a later model Turbo 400? Also, the motor rear main seal is leaking. Can this be repaired without pulling everything apart once the tranny is removed? Link to comment Share on other sites More sharing options...
rocketraider Posted March 11, 2009 Share Posted March 11, 2009 61-64 Olds and short wheelbase Pontiacs will be a near drop in. A Super HydraMatic from a 61-64 Bonneville/Star Chief will bolt up to the engine using the Olds bellhousing extension but may run into clearance problems on the trans tunnel.Your keyword here is easily. Any 65-later transmission either requires an adapter or modifying the case to bolt up to the Rocket engine.Just curious where you're located? We may be able to find you a HydraMatic guy close by.You'll have to drop the oil pan and rear main cap to replace the rear main seal.No one said living with an early 60s Olds was easy. Link to comment Share on other sites More sharing options...
Guest wk's_olds Posted March 11, 2009 Share Posted March 11, 2009 The '61 Olds tranny is called a slim jim. I replaced one in a '61 Dynamic 88 just a couple of years ago. I got it in Denver from a rebuild shop there. It works perfectly. They can still be rebuilt. They are a pretty good unit. Link to comment Share on other sites More sharing options...
Starfire61 Posted March 12, 2009 Share Posted March 12, 2009 Could you be more specific about the problems you're having with the transmission? The Roto-Hydramatic is extremely sensitive to TV linkage adjustment. Even when operating properly its quirks may lead one to think that it's broken....Please tell us your location.Chuck Link to comment Share on other sites More sharing options...
rocketraider Posted March 12, 2009 Share Posted March 12, 2009 Just for clarification, the 61-64 Olds HydraMatic is known as:Roto-HydraMaticRoto 10Slim Jimand POS. They're also very sensitive to fluid level as well as the throttle linkage adjustment.I think the biggest reason trans guys don't want to fool with them is because they don't want to warranty it. It's no worse than some other units, but its reputation precedes it... Guy fixes electronic transmissions all day and then tries to tell me he can't work on a simple fluid coupling box? Bah, phooey. Link to comment Share on other sites More sharing options...
Desolow52 Posted March 12, 2009 Author Share Posted March 12, 2009 I have never driven the car, I have only heard it run. The previous owner said the car does drive but it changes poorly between 2nd and 3rd because the carb works via the kick down rod off the tranny it affects the rpm when changing gear. The price was right so I just bought it and I figured I would troubleshoot it once I got it home. After hearing some of your input, it sounds like it might not be a major issue after all..... Link to comment Share on other sites More sharing options...
rocketraider Posted March 13, 2009 Share Posted March 13, 2009 PO has it backwards. The transmission shift points are controlled by the throttle linkage opening, and if he knows how these things work, the 2-3 shift (often and usually mistaken for the 1-2) can be very rough with a sharp RPM drop. My blue Starfire would sometimes stall out at a low speed 2-3 shift, the engine speed dropped off so far. Wasn't quite as bad if you were into it a little.Get a 1961 Olds factory shop manual. It will have everything you need to troubleshoot the Slim Jim except the special tools used to adjust the throttle valve linkage. Link to comment Share on other sites More sharing options...
Guest 61Super88-4dr Posted March 20, 2009 Share Posted March 20, 2009 Kind of in same boat here. 1961 Super 88. Rebuilt my 394 motor and the tranny stopped working right when I reassembled the motor to tranny. Had a core rebuild by a local tranny shop and they were unable to get it shifting right. So they are now rebuilding the original. My price tag will end up being $1500-$3000 to get it done and no garentee. Theres a place in Ham Lake Minnesota that sells adapter kits to adapt to newer transmissions like newer s10 tranny or GM etc. But thier price is $1495 for a kit. I would exhaust having the TV adjustments looked at before heading down the road I went. Link to comment Share on other sites More sharing options...
Talarico8447 Posted March 23, 2009 Share Posted March 23, 2009 Don't ever give up on a Roto-Hydramatic. You take care of your Slim Jim and it will take care of you. Link to comment Share on other sites More sharing options...
d2_willys Posted April 13, 2009 Share Posted April 13, 2009 Try talking to:Tony __________________Ross Racing EnginesNiles,Ohio330-544-4466 w330-720-1282 c He has just come up with a new adapter that will allow Turbo 400 modified transmissions to bolt to first gen Olds Rockets. Link to comment Share on other sites More sharing options...
RShepherd Posted May 10, 2009 Share Posted May 10, 2009 <div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: wk's_olds</div><div class="ubbcode-body">The '61 Olds tranny is called a slim jim. They are a pretty good unit.</div></div> Compared to what? I can't think of a poorer performing automatic transmission even when brand new. The most annoying characteristic was the slip-and slide-then jerk, takes -forever, gap-as-wide-as-the Grand Canyon 1-2 shift which often left the engine flat-footed at 15-20 MPH. My dad was, like Ralphie's father in The Christmas Story, "an Oldsmobile man" but his continuous run of Oldsmobiles which began in 1937 almost ended after owning a '64 Ninety-Eight with that transmission. After he drove his brother's new 1965 Delta 88 with Turbo-Hydramatic, he said he couldn't believe that those two cars were built by the same company a year apart. Link to comment Share on other sites More sharing options...
KQQLCAT Posted July 7, 2009 Share Posted July 7, 2009 I thought I would put a picture of Ross Racing Engines transmission. This is a TH400 and comes with flywheel and torque converter. Nice piece. I plan on this swap. Link to comment Share on other sites More sharing options...
rocketraider Posted July 7, 2009 Share Posted July 7, 2009 Let us know how everything works out, especially tunnel clearance and floorshift linkage. That's the best-looking adapter I've seen. How much machine work needed to put it on, or do they do that for you?Hmm- 394, Turbo 400 and 3.42 gears ought to really wake up a Starfire. Link to comment Share on other sites More sharing options...
Hurst_Olds_1968 Posted July 7, 2009 Share Posted July 7, 2009 Nice, what is the cost on that set up???Will it clear the stock 61-64 Trans tunnel??????Vinny Link to comment Share on other sites More sharing options...
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