I started a previous thread thinking my truck was having an issue in Drive (3rd) going temporarily into neutral ... after reading and searching and driving it around I am pretty sure that the feeling I have is the Torque Converter Clutch (TCC) unlocking and locking in 3rd gear - I do have the O/D off button pushed in.

I have looked at TSB 18-02-99 and it seems to describe my symptoms, except, the TSB is about the problem in 4th gear (O/D).

I have 35" tires and the ECM is not calibrated for them, but the problem has only recently manifested itself and the tires have been on for a while.

The transmission has been rebuilt (as of 05/25/06) by a local shop - in retrospect I should have taken to a tranny shop or the dealership as my mechanic is unable to understand the torque converter locking and unlocking, although the tranny does shift nice - and no more squeaking from the broken spring.

I'm going to go out and clean the battery cables and look for any ground connections that need to be cleaned or tightened.

Anywhere else I shoud look?

Where is the PCM on a 99?

Should I get the ECM calibrated for the tire size (and does that require the dealership?)?

Thanks,

Casey

PS I posted in the wrong forum, can an admin move this to the 2nd generation forum? TIA

 

It's not the battery cable that are the problem. It's the grounding of the body of the truck and the ECM.

Do a search for more info and where to run a new ground.

 

The problem is noise on the line that controls the TC lockup. This can have mutliple sources and causes. A couple of quick things to check are all battery connections tight and clean, both batteries must be good and test good on a tester, make sure the grounds are scraped to metal and use dielectric grease on them. Last, reset the APPS. PM me and I can forward you the complete list of things to check and do to eliminate the problem.

 

I endured months of this problem but the locking/unlocking was in 3rd and 4th gear. I bought a DTT noise filter but before installing it I tried the Dunrite tin foil fix described on the home page of the "other" site. Works perfectly. Five hundred miles now and no problems. My tranny controller overrided the problem but there were times in stop and go traffic when I desired softer,closer to stock shifts and Dunrite worked for me. Total cost:about a buck. Time:20 minutes if that!