QuestionQUESTION: I think the torque converter is not locking up - when I cruise the RPM is higer than it used to be. When I take my foot off the gas the RPM drops a few hundered, then will jump up again when I accelerate. No shifting problems,but fuel consumption has increased. I read the codes and there is nothing stored, the trans fluid is good (no burnt smell, etc). 102,000 miles, never rebuilt. Recently had the radiator replaced. Any idea what to look for? Thanks!
ANSWER: Hi Witold,
I assume that you have the 4-speed electronic transaxle. There is a torque converter clutch that is activated hydraulically. The electronics control the activation of the hydraulic valve that applies pressure to the clutch. That valve is located in the valve body of the transmission which is accessible by dropping the pan underneath it. If it is not that valve, then it has to be the clutch in the torque converter proper as there is no dedicated wire/circuit for just the activation of that valve. I would probably not attempt to repair it at this point but rather wait for the need to do more drastic repair of the unit when you get into problems that require a rebuild. Just be sure to add the torque converter issue into the plan at that time.
Roland
---------- FOLLOW-UP ----------
QUESTION: Hi Roland,
Thanks very much for your response. Yes, this is a 4-speed electronically controlled transmission. Does it make sense that I cannot see any codes? I would think that if the valve was stuck or the clutch not working the controls would flag it. I have never worked on automatic transmissions before - it is a big job to get to the valve? Do you have any links that show how to do it?
I have to take my daughter to college in four weeks - it is about 350 miles each way so I would like to avoid taking the risk.
Best regards,
Witold
AnswerHi Witold,
The '96 model year is at margin between the OBD-I and II system and for that reason I am not certain what device you would need to read transmission codes and which system they would be logged as. In OBD-I it would be a transcode 37, and in OBD-II it would be P0740. So that is the first issue to consider. You didn't specify which reader you used so I can't conclude anything except that you observe the torque converter doesn't lock up.
I can't say how big a job it would be but it does have some pitfalls:
You drop the pan and collect the trans fluid. Then the filter is removed and the transmission range sensor and finally the valve body. The you have to partially disassemble the valve body and inspect the torque converter control valve. That last part involves a myriad of springs, pistons, clips, etc. and thus lies the possibilitiy of parts becoming dislodged and not knowing where they go. The manual shows many of the steps but not in great detail.
If you recognize that many automatic transmissions in the past did not have torque converter clutches and thus are behaving as yours does now, it lessens the concern except for that of fuel efficiency. I would believe the risk of getting into this repair and not succeeding exceeds that of leaving well enough alone.
Roland
PS: Because of the likelihood that other will develop this problem and nothing personal appears to be involved, I am taking the liberty of making my response public.
