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A few months ago I bought this 1990 Chevrolet Beretta GT just for a drive around town car. When I first got it, I had to replace a torque coverter switch down on the side of the engine, because the car would jerk like it had a stick shift in it when you slow down and forget to push the clutch in. Anyways, I think the car had been driven awhile with this bad switch which may have caused the problem that I have now. Mostly the car jerks while in the 45mph to 55mph range. Anything below or above those speeds it drives like a dream. Could it be that the torque converter was damaged during this time that the switch was bad? Because it acts like a sloppy converter, and always seems to be acting up when the converter is trying to lockup in the 45 to 55mph range.
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i doubt that your vintage of vehicle will have on board diagnostics or computer controlled transmission. any diagnostics performed would have to be rudimentary. from what you describe the problem is with the torque converter clutch (TCC). I am not sure what inputs your vehicle accepts in order to determine when to apply the clutch, but here is one possibility to consider:
Turbine speed sensor (TSS)
This may also be known as an input speed sensor (ISS). This sensor sends a varying frequency signal to the TCU to determine the current rotational speed of the input shaft or torque converter. The TCU uses the input shaft speed to determine slippage across the torque converter and potentially to determine the rate of slippage across the bands and clutches. This information is vital to regulate the application of the torque converter lock-up clutch smoothly and effectively.
if your vehicle was 1996 or newer, the diagnostic procedure would be much more exact and would include using a techII scanner (or better) and commanding the computer to lock the TCC. one could also test drive the vehicle and view real-time data on what is actually happening with your transission.
one diagnostic test you can perform though, would be to locate and disconnect the electrical connection for the TCC solenoid, which would most likely be located on the front of the transmission and see if this eliminates the problem. if the problem is resolved, then the problem is the clutch. It might pay off to do your homework; google what specific transmission your vehicle has, then look for an exploded view of the transmission. You’ll know exactly where to find your TCC solenoid.
what you describe is a common and known problem with TCC’s:
- Symptom: car shudders around 35-40mph (second gear) as a general rule for most vehicles.
- Cause: bad torque converter clutch
- Solution: replace the torque converter
Tips:
you can get away with just leaving the TCC solenoid unplugged and avoid having to do a time consuming repair; however, expect a 10% reduction in fuel economy.if possible, review the alldata recommended procedure for torque converter remove & replace. this will give you an overall idea of what you’re getting into. also, see if there are any available youtube videos for your vehicle. you can learn a lot from someone else’s struggle.
you must ensure you hear a ‘double clunk’ when installing your torque converter; it has to seat once on the front oil pump splined shaft and again for the transmission input shaft. Here is one video that demonstrates this:
Based on your description it’s almost a text book torque converter problem. As stated you could leave it unplugged but it will cost you fuel economy.
If I unplug the TCC solenoid and leave it unpluged besides losing some gas milage won’t it also cause my engine to run hotter?
there will be no other significant effect other than perhaps a negligible decrease in fuel economy. :side:
Okay I’m gonna give it a try…………..Thanks for your input, I’ll let you know what happens. It may be a couple of days because the weather is kinda nasty right now. Thanks again.
The TCC has nothing to do with the operation of the cooling system so no, you wouldn’t notice anything else.
This is essentially what my truck has been doing and everyone said it was not torque converter related. Only difference is that it keeps jerking above 55 mph. I even suggested a speed sensor and it was more or less ruled out.
Had this same issue on my 89 Corsica 2.8L. I unplugged the TCC connector and left it like that for 3 years before the car went for scrap. Your MPG will suffer slightly. No other issues to worry about.
This is essentially what my truck has been doing and everyone said it was not torque converter related. Only difference is that it keeps jerking above 55 mph. I even suggested a speed sensor and it was more or less ruled out.
LJ11194, it might be worth your time to try disconnecting the solenoid despite what everyone else says and see if you experience any improvement. Other causes of vehicle shuddering could include worn bushings in your suspension system.
Would the connector for the solenoid be something easily identifiable on the outside of the transmission? I have a factory service manual but it isn’t completely clear on where this plug is.
get me the year/make/model and engine size of your vehicle and i can get you the component location from alldata since i’ll be at school the rest of the day. :side:
Thanks. It’s a 1999 Dodge Ram, 5.2L. It’s a gas engine so it should have a 46RE transmission. However it isn’t stock, it’s a Jasper aftermarket one and I have no idea if that makes it somehow different.
This is what I’ve come up with after briefly looking at Alldata. Luckily, the electrical connections will remain the same despite whatever transmission you have. Below are the electrical diagrams, connector and module locations. The possibilities here are endless; it’s just a matter of what is easy to get to and your personal preference of how you’d like to interrupt the TCC solenoid circuit. Keep in mind that this is just a diagnostic procedure, the cause of your shuddering could be from something else so make sure that whatever you do can be easily reversed if necessary.
Thanks alot. I don’t really know which of these would be best to do though. I’m only at a basic level with mechanical work and I don’t touch electronics much beyond plug and play.
It’s also worth noting I have occasional misfires in 3 cylinders. They only throw CELs above 4 grand but I’m pretty sure they’re always there. I have a blown plenum gasket and recently ordered the kit to fix it, (its coming tomorrow, who knows when it’ll be installed though) so would it be worth seeing if the missing is causing the TCC to slip? I know for a fact that it only shudders when the TCC is locked, so it isn’t JUST the missing.
a vacuum leak can greatly affect overall shift performance. when it comes to TCC application however, the only affected criteria would actually be ‘when’ the TCC is applied. for example, the computer might sense the vacuum leak as an engine that is under load and could delay shifting and TCC application. from what you’ve described the cause would most likely be a defective torque converter clutch since there is no correlation between vacuum associated transmission inputs vs. quality of the torque converter lock-up. It could be possible that the PCM might rapidly cycle the TCC solenoid; however, this is unlikely.
Q: how many miles are on your vehicle/engine/transmission
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