Hi everyone! I still don't have a wagon, but I really could do with your advise. I have an 88 GMC Vandura Starcraft conversion Van. It has the 5.7 tbi engine coupled to a 700R4 and an LPG conversion. Once in a while I experience a stutter in the transmission of which I am almost 100% positive is the lock-up vibrating. I also suspect that it does not really lock-up in 3rd (as should be, I thought) but when shifting to overdrive. This often results in such a big rpm drop that it will shift up again and go back and forth until speed (read rpm) has been increased enough. This is around 45 mph. I was advised by some to disengage the lockup (I have an extra big oil cooler) or to make a switch to switch it off. The last advise I will do, as the LPG conversion has decreased the power, resulting in shift rpm's that are actually a bit too low and disabling the lock-up at lower speeds can give a bit more power. Anyway, besides many disadvantages in disabling the lock-up, I have a principle problem with disabling systems when they don't function. I am not really familiar enough with the lock-up system to reason what could be wrong, so I hope someone can point me in the right direction. Thanks
Lock-up clutch is going bad - you might get away with switching the converter, before it goes all the way bad and ruins the trans itself.
