Another DSP6 issue - slipping into neutral with no shift?
Posted: Thu Feb 05, 2026 7:33 am
I'll check codes and some live data when I can, but wanted to start the thread while I'm thinking about it.
Recently I replaced the clutch and all associated items inside plus the two motors for the forks. I had thought I screwed something up because it was overheating and telling me to pull over and rest the car for 5 minutes sometimes. But I had also replaced the rear main seal cover with a Fel-Pro one when I had done the clutch. Turns out it promptly leaked worse than the OE one I took off and was causing massive slippage. The whole inside of the trans was covered in engine oil. After a lot of cleaning, no more overheating.
But now I'll be driving along and suddenly it will rev to the moon and won't engage the clutch at all. Yes, Forscan programmed everything successfully, and yes, I reprogrammed it after the last dismantling, and yes, I have the latest firmware on the TCM.
Could it be that I just have a bad TCM now? I hear the electronics can go bad - capacitors or other items susceptible to age. This would actually be the best solution since I could replace it without dropping the transmission again. I don't want to drop the trans again.
I would think that if slippage was the issue again, that I'd just get overheating again, but would at least be able to move the car when the runaway revs happen.
Is there any way that the shift linkage could shift to neutral without the shift knob moving? How would I test for that?
Also, what live data should I look at? And is it true that if the TCM is failing that there may be no codes? If I am code free altogether, would that indicate a TCM issue?
Recently I replaced the clutch and all associated items inside plus the two motors for the forks. I had thought I screwed something up because it was overheating and telling me to pull over and rest the car for 5 minutes sometimes. But I had also replaced the rear main seal cover with a Fel-Pro one when I had done the clutch. Turns out it promptly leaked worse than the OE one I took off and was causing massive slippage. The whole inside of the trans was covered in engine oil. After a lot of cleaning, no more overheating.
But now I'll be driving along and suddenly it will rev to the moon and won't engage the clutch at all. Yes, Forscan programmed everything successfully, and yes, I reprogrammed it after the last dismantling, and yes, I have the latest firmware on the TCM.
Could it be that I just have a bad TCM now? I hear the electronics can go bad - capacitors or other items susceptible to age. This would actually be the best solution since I could replace it without dropping the transmission again. I don't want to drop the trans again.
I would think that if slippage was the issue again, that I'd just get overheating again, but would at least be able to move the car when the runaway revs happen.
Is there any way that the shift linkage could shift to neutral without the shift knob moving? How would I test for that?
Also, what live data should I look at? And is it true that if the TCM is failing that there may be no codes? If I am code free altogether, would that indicate a TCM issue?