Reatta90 Posted June 28, 2017 Share Posted June 28, 2017 Hey guys, I recently did a transmission replacement on my 90 reatta, although I did use a used transmission because o a tight budget at the time. I've encountered an issue, the transmission seems to act up or appears to be the transmission acting up. It does this jerking like thing where it isn't necessarily a shudder but pulls and shakes really hard when the temperature reads 65 or below and I notice the problem when I'm driving 70 mph or better and it doesn't do it if I'm giving it gas but as soon as I let off itll start jerking and pulling and shaking. I understand I went wrong with the transmission being used and all but I just wanted to see I there were any ways of fixing this issue or maybe anyone had an idea of what is happening? Link to comment Share on other sites More sharing options...
Ronnie Posted June 28, 2017 Share Posted June 28, 2017 10 minutes ago, Reatta90 said: when I'm driving 70 mph or better and it doesn't do it if I'm giving it gas but as soon as I let off itll start jerking and pulling and shaking. I would be really surprised if the transmission would be the cause of jerking and shaking when you let off the gas. Transmission problems usually occur when the transmission is under load. A lot of things could be causing the problem. Do you have any trouble codes showing in the on-board diagnostics? How To Access ECM, BCM & CRT Codes 3 Link to comment Share on other sites More sharing options...
drtidmore Posted June 28, 2017 Share Posted June 28, 2017 As Ronnie posted, normally you detect a transmission issue UNDER load as that is the maximum stress on the transmission. Do you have ANY idea of the miles that were on the transmission that you installed? Did you pull the bottom pan to inspect for things that should NOT be there? Did you think to cut open the filter and pull it apart to verify for metal, clutch material (FYI, the incoming fluid goes into the INSIDE of the filter rather than being pulled thru from the outside, so you have to chisel the filter housing open and then separate the filter material halves to check for chips of clutch material, metal shavings, etc). Were you able to drive the Reatta BEFORE you replaced the transmission and if so, did you detect anything similar to what you are now experiencing? What is the shift behavior under normal acceleration from a standing start (i.e. at what speed does it shift in each gear/are the shifts smooth and positive)? Does it downshift properly under hard acceleration from a moderate speed start (i.e. such as needing to pass a vehicle at highway speeds)? Before making any judgement as to what is causing your drivability issue, more information is needed. 1 Link to comment Share on other sites More sharing options...
Reatta90 Posted June 28, 2017 Author Share Posted June 28, 2017 (edited) Okay, so basically upon getting the transmission, I cleaned the entire thing inside and out. And it had 100k on the tranny. I replaced the filter, gaskets, and the pan had no signs of metal shavings. Although, if I recall, it did shake and jerk with the old one. But the old one had lots of problems shifting and would shutter when trying to put a load on it around second gearish. And I read somewhere that ignition modules can be the source of jerks in cold weather? But the module is fairly new as well as the coil packs. It's been upgraded to the ac Delco setup. And it has a little bit of give when shifting but it is an older transmission that is a 4 speed that I wouldn't expect anything better, I believe it shifts fairly well when doing so. But I do believe it will sometimes have this acceleration and then deceleration feeling occasionally in the cold weather and the rpm will go up one and fall down one. And yes it will down shift, sometimes it feels like it requires more acceleration than needed to get the car to do it but yes under load it will down shift. I believe it shifts the fist time below 20, then at like 47/48, and then will shift between like 55 again and then shifts again around like 70 I believe. I've checked my vacuum lines and they all seemed to be doing just fine, I replaced a few on the transmission because of the fact that they had been messed with when doing the transmission so I went ahead and replaced them. It has new fluid in the transmission as well as the filter, and has new gaskets and the fluid levels are great. The guy I bought the car from was running full synthetic, so I tried to just convert back to huh mileage, took a little more because I wanted to make sure I cleaned the high mileage out and then did another oil change shortly after to be sure to get the synthetic out, because I've read if your oil is too thick it can clog the sensors and mess the timing up so I thought that might be it, but it wasn't. And I thought it wasn't a transmission thing, I mean I have some knowledge, but I'm no where an expert nor is it something I've experienced before. Also, no engine codes are present to make it happen. Edited June 28, 2017 by Reatta90 (see edit history) Link to comment Share on other sites More sharing options...
Ronnie Posted June 28, 2017 Share Posted June 28, 2017 5 minutes ago, Reatta90 said: I believe it shifts the fist time below 20, then at like 47/48, and then will shift between like 55 again and then shifts again around like 70 I believe. I assume those shift points are at full throttle? Those shift points seem to be really high to me. Perhaps the throttle valve (TV) cable that connects to the throttle linkage is out of adjustment. If so it would cause the transmission to wait much longer to shift with the throttle open AND it would cause the transmission to downshift erratically when you let off the gas. The TV cable may not be your problem but it is something that should be checked since you had the transmission out and probably had the TV cable disconnected. 1 Link to comment Share on other sites More sharing options...
Reatta90 Posted June 28, 2017 Author Share Posted June 28, 2017 Yes, in fact you are right it is, and I have tried adjusting it, but I wasnt sure that if you adjust it too much if you can damage the transmission. I did notice that I with get better response or worse response when trying to adjust it. And when i.mean adjust, I would just tighten the cable or loosen the cable. I was having problems having no pick up and I discovered it was that cable. And I adjusted it and that was a happy medium. I know I need to replace it, I just was doing something in mean Time. But to see if this is the issue, do I want to make the cable tighter or looser? Link to comment Share on other sites More sharing options...
89RedDarkGrey Posted June 28, 2017 Share Posted June 28, 2017 Link to comment Share on other sites More sharing options...
Ronnie Posted June 28, 2017 Share Posted June 28, 2017 I believe the proper way to adjust the TV cable is this: Press the adjuster release and pull the cable all the way back. Then get in the car - engine OFF - and press the gas pedal all the way to the floor. Then release. IF the cable adjuster is working properly the cable should ratchet to the proper position when you press the cable all the way down as described above. 1 Link to comment Share on other sites More sharing options...
Reatta90 Posted June 28, 2017 Author Share Posted June 28, 2017 Thank you so much! So will this fix my issue with the shaking? You've guys been a big help. While I have your attention. What is the component that runs into the firewall on the passenger side where the high and low pressure lines feed in for the a/c, it neighbors the heater core. I have replaced the heater core but never noticed that component there so I was curious, and what extra would I be looking at in replacing it. Thank you guys again, hopefully one day I can have this realm.of knowledge you guys seem to possess Link to comment Share on other sites More sharing options...
DAVES89 Posted June 28, 2017 Share Posted June 28, 2017 (edited) I agree with the others that it probably isn't your transmission. However I believe you should get the throttle cable sorted out and I think the video 89rdg provided and the tip from Ronnie should help with that. I think the problem lies with either the MAF sensor or ignition module and I'm leaning more to the MAF sensor. I am an old parts swapper and I like to have extra known good back up parts ready to be used. Edited June 28, 2017 by DAVES89 (see edit history) Link to comment Share on other sites More sharing options...
Reatta90 Posted June 28, 2017 Author Share Posted June 28, 2017 If it is the MAF, why are there no codes being thrown? Link to comment Share on other sites More sharing options...
2seater Posted June 28, 2017 Share Posted June 28, 2017 1 hour ago, Reatta90 said: If it is the MAF, why are there no codes being thrown? One of the oddities of just about any sensor is: it may be giving bad information, but a code may only set if there is no information. The ECM has default and safe readings built in in case of sensor failure, it will set a code but generally will get you home. One way to test the MAF is to tap on the plastic cover while idling, which may cause a stumble, verifying it has a problem. The second is to pull the sensor and check the fine wires at the tip for any contamination, which can be cleaned with a MAF safe spray. A third test is to operate the engine with the MAF disconnected, which will force the ECM to use stored information. You will get a check engine light. You can also monitor the MAF, or almost any sensor, through the diagnostic mode to see if the readings look odd. 1 Link to comment Share on other sites More sharing options...
drtidmore Posted June 28, 2017 Share Posted June 28, 2017 3 hours ago, Reatta90 said: The guy I bought the car from was running full synthetic, so I tried to just convert back to huh mileage, took a little more because I wanted to make sure I cleaned the high mileage out and then did another oil change shortly after to be sure to get the synthetic out, because I've read if your oil is too thick it can clog the sensors and mess the timing up so I thought that might be it, but it wasn't. And I thought it wasn't a transmission thing, I mean I have some knowledge, but I'm no where an expert nor is it something I've experienced before. Also, no engine codes are present to make it happen. First thing to know is that Dextron VI IS the correct fluid for ALL GM TRANSMISSIONS regardless of year of manufacture, PER GM! In fact, GM goes further and states that they no longer license the manufacture of ANY of the previous Dextron formulations as Dextron VI supersedes ALL previous formulations. So at this point, the ONLY formulation that has licensed and monitored specifics is Dextron VI (and by the way it IS pure synthetic). Not exactly sure what fluid the previous owner was running or what was used in the replacement. There are NO sensors per se in the transmission as it is a pure hydraulic controlled unit using nothing more than an internal mechanical pressure governor run off the output shaft, the throttle body valve (sets shift points relative to throttle position), the vacuum modulator (tweaks the shift points) and pressures in the valve body to control the position of several spool valves that in turn coordinate the two bands and 4 clutches (FYI, the 4 clutches are NOT the same as the 4 gears, but rather the 4 clutches and the two bands work together to produce the 4 forward gears and reverse). That said, running the WRONG fluid CAN mess with seals as well as the operation of the valve body. Ronnie already gave you the proper way to adjust the TV cable. It is NOT proper to attempt to adjust it to compensate for other problems. If you set it such that full throttle fully extends the TV cable, then that is where to leave it. FYI, the purpose of the TV cable is to progressively delay the shift point relative to engine RPM such that at wide open throttle, the transmission will almost require redline engine RPMs before it shifts (VERY HARD ON BOTH). FYI, while the Reatta has an excellent self diagnosis capability, there are MANY things for which NO codes are present. For instance the ICM (ignition control module) which is responsible for buffering the crack and cam sensors as well as controlling the spark timing has NO codes whatsoever. So don't be lulled into believing that no codes means all is well. 1 Link to comment Share on other sites More sharing options...
drtidmore Posted June 28, 2017 Share Posted June 28, 2017 (edited) 3 hours ago, Reatta90 said: Thank you so much! So will this fix my issue with the shaking? Most likely will NOT fix your problem as the TV cable only adjusts the shift points relative to the throttle position. You most likely have an engine control issue but it is too early to rule out a transmission issue entirely. Issues like you are experiencing typically require a process of elimination and that does NOT equate to throwing parts at it in hope of a quick fix, NOR does it mean blindly trying to adjust something. Edited June 28, 2017 by drtidmore (see edit history) Link to comment Share on other sites More sharing options...
Reatta90 Posted June 28, 2017 Author Share Posted June 28, 2017 Okay, I mean the engine oil was running synthetic, not the transmission. I am running he correct fluid in the tranny. But I will certainly go check the MAF and test some ignition modules on the car and see what I come up with. Thank you for the suggestions. Although, my only problem is I know how to get the codes to pop up and all that, I just don't know how to run the diagnostics and what exactly should be prevalent on what ever section I should be observing Link to comment Share on other sites More sharing options...
2seater Posted June 28, 2017 Share Posted June 28, 2017 The classic symptom of ignition breakdown is a shudder at about 50 mph under moderate acceleration, where the trans. goes to 4th gear and the TCC locks up. Not meant as an insult, but have you verified the spark plug routing is correct? This one has bit many over the years, primarily the rear cylinders. I saw in one of 89RDG's video's that the 3800 will idle smoothly on only two cylinders. Verify spark on all three coils. 1 Link to comment Share on other sites More sharing options...
KDirk Posted June 28, 2017 Share Posted June 28, 2017 I too will suggest a possible ignition control module fault. I had this and swore it was a tranny issue for a long time until the ICM died and the repalcement also eliminated the shudder at highway speed. Do check the routing of the plug wires also the FSM is wrong for at least the 1988 edition and has the even and odd cylinder banks reversed, which has probably lead some to unknowingly screw up the firing order by following what the book says. The MAF is also a possible suspect, so don't rule it out until proper operation is confirmed. Try not to rely heavily on the on board diagnostic. It is nice as far as it goes, but not comprehensive enough to accurately pinpoint many issues without some old fashioned seat of the pants troubleshooting. 2 Link to comment Share on other sites More sharing options...
89RedDarkGrey Posted June 28, 2017 Share Posted June 28, 2017 My way to properly clean a MAF= remove it from it's housing (3 screws, 1 O-ring) get a can of MAF CLEANER (CRC) and using the black plastic cap of the can, attach the straw, and slowly fill the cap with cleaner. Stand the nose of the MAF in the cap, immersing in cleaner. Let sit 30 minutes. The key is to soak it. After- use the spray to remove any contaminates, spray about 10 seconds- never a Q-tip or anything ever should touch those delicate tungsten filaments. Link to comment Share on other sites More sharing options...
drtidmore Posted June 28, 2017 Share Posted June 28, 2017 (edited) 3 hours ago, Reatta90 said: Okay, I mean the engine oil was running synthetic, not the transmission. I am running he correct fluid in the tranny. But I will certainly go check the MAF and test some ignition modules on the car and see what I come up with. Thank you for the suggestions. Although, my only problem is I know how to get the codes to pop up and all that, I just don't know how to run the diagnostics and what exactly should be prevalent on what ever section I should be observing With that cleared up, I can say that running synthetic oil will NOT harm the engine or its sensors. My Reatta 3800 has been on synthetic since DAY 1! If you are not getting the SES (service engine soon) light on the dash, then any codes that are setting are NOT drivability related (and some SES setting codes won't impact drivability to any great extent). When we discuss diagnostics, we ARE talking about the codes but it is up to YOU or your mechanic to sort out what to do. Based on the questions you have asked, I am assuming that you don't own a '90 Reatta/Riv Final Edition field service manual. GET ONE! You can't begin to maintain the Reatta without the FSM. Yes, this site is a wealth of information, but the site is not a substitute for looking up information in the FSM. The FSM is NOT a DIY guide but the troubleshooting and explanations that it contains are invaluable. In thinking back over conditions with symptoms even remotely similar to what you are describing, the only thing in my experience that was transmission related was a blown out vacuum modulator valve that was sucking transmission fluid out at just low enough rate to not cause smoke and once the fluid level got low enough, the downshift to 2nd gear on deceleration became VERY abrupt, but that is not really close to what you are describing. Regardless, I would check the vacuum modulator to ensure that it is working and will hold a vacuum properly. If you replaced it, understand that all the new ones have to be adjusted to find the sweet spot for the shift points (they come set in the middle of the their range). There is a small set screw in the end of the vacuum connection. All the way counterclockwise softens the shifts (more slippage) and all the way clockwise produces harder shifts (less slippage). On a high milage tranny, LESS slippage is preferable as you are typically on borrowed time anyway. Edited June 28, 2017 by drtidmore (see edit history) 2 Link to comment Share on other sites More sharing options...
Reatta90 Posted June 29, 2017 Author Share Posted June 29, 2017 What is the firing order, and I will clean the MAF and I will adjust the modulator some, and I will test the ignition module. Thank you guys! Link to comment Share on other sites More sharing options...
DAVES89 Posted June 29, 2017 Share Posted June 29, 2017 1-3-5 in front 2-4-6 in back left to right as you face the engine. You can't adjust the modulator if you don't have an aftermarket one. 1 Link to comment Share on other sites More sharing options...
89RedDarkGrey Posted June 29, 2017 Share Posted June 29, 2017 On 6/28/2017 at 6:46 PM, drtidmore said: If you replaced it, understand that all the new ones have to be adjusted to find the sweet spot for the shift points (they come set in the middle of the their range). There is a small set screw in the end of the vacuum connection. All the way counterclockwise softens the shifts (more slippage) and all the way clockwise produces harder shifts (less slippage). Scroll through the views- http://www.rockauto.com/en/moreinfo.php?pk=1187486&cc=1019911&jsn=460 On 6/28/2017 at 8:02 PM, Reatta90 said: What is the firing order 1 Link to comment Share on other sites More sharing options...
Reatta90 Posted June 29, 2017 Author Share Posted June 29, 2017 The coil packs aren't set up the same, mine all are in one line, like the plugs all go in a line but the engine set up is the same Link to comment Share on other sites More sharing options...
DAVES89 Posted June 29, 2017 Share Posted June 29, 2017 The coil pack is in line but should be numbered. Use the refernce listed above to run the spark plug wire to the correct coil. Link to comment Share on other sites More sharing options...
DAVES89 Posted June 29, 2017 Share Posted June 29, 2017 6-3-2-5-4-1 with #6 farthest away from you on an in line Delco set up. 1 Link to comment Share on other sites More sharing options...
89RedDarkGrey Posted June 29, 2017 Share Posted June 29, 2017 Link to comment Share on other sites More sharing options...
Reatta90 Posted June 29, 2017 Author Share Posted June 29, 2017 THANK YOU! 1 Link to comment Share on other sites More sharing options...
89RedDarkGrey Posted June 29, 2017 Share Posted June 29, 2017 1 Link to comment Share on other sites More sharing options...
SCOTT's 90's Posted January 25, 2018 Share Posted January 25, 2018 Is there an update to this post and what was the solution if any? Thanks 1 Link to comment Share on other sites More sharing options...
89RedDarkGrey Posted January 25, 2018 Share Posted January 25, 2018 That happens a LOT. A LOT. They either give up, ruin something, have it repaired- or find out the repairs "exceed the worth of the vehicle" and get rid of it. Kind of disappointing, actually. 1 Link to comment Share on other sites More sharing options...
SCOTT's 90's Posted January 25, 2018 Share Posted January 25, 2018 Yeah I know what you mean, hopefully that is not the case. I guess we will see. Link to comment Share on other sites More sharing options...
Reatta90 Posted January 25, 2018 Author Share Posted January 25, 2018 (edited) Hey Guys, I actually did follow the advice and tried the ignition module, and the problem went away. I got another vehicle which allows me to set the Reatta as my project/weekend driver. I'm currently working on getting the ball joints, and power steering fixed. The car has a really bad leak on the power steering pump and also has an issue of wandering the road a lot which gives the car poor handling. Sorry for lack of update, I'm not always going to be the only one seeking this information. But the ignition module was a definite fix. Thanks to these guys on the forum I was able to survive the reigns of terror from car troubles. Edited January 25, 2018 by Reatta90 (see edit history) 2 Link to comment Share on other sites More sharing options...
SCOTT's 90's Posted January 26, 2018 Share Posted January 26, 2018 Thanks for the Update! Happy it all worked out for you - If you go to a pick yard to get an ICM your chance of getting a good one is 50/50. Link to comment Share on other sites More sharing options...
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