The 960 tranny has been acting strange. I've already replaced all the fluid and just in case drained and refilled a couple of days ago. I'm using Shell Dexron III ATF.

WOT in "D", holds near 6,000RPM every time 1-2 before upshifts, downshifts fine, shifts fine, never one sign of any trouble except the lockup function has sometimes seemed a little overactive when cruising, in the past, that's it.

Here's the problem: WOT while it is already in first, just starting out if you drop it into "L", you feel a bump, then it feels like a loss of acceleration though the RPM's don't surge like it's slipping. It's kind of like it actually shifted into second early, not exactly sure though. It also upshifts early like 4500RPM when it does this. It has began to do this pretty consistantly a while ago and never did this prior. I like to use "L" and manually up shift to 3rd then D because I can usually get it to hold out a little more until right at 6,000RPM for a nice launch into second gear. I've been driving it hard on a fairly regular basis to try and free these sticky lifters, been running synthetic etc.

After this started, while stopped with my foot on the brake, I moved the shift lever up and down several times hoping to maybe refresh the PNP switch contacts to see if it helped. Seemed to stop and hadn't done that for a while after that.

Is this likely due to a failing PNP switch since it's shift related and is perfect otherwise? Second question, if the CEL doesn't illuminate is it still possible there may be a tranny code stored or is this unlikely?


Thanks in advance for any help on this!