SilverDollar

This is my first post to this forum. Great reading and always helpful. I have a problem however, that I'm not sure has been covered. If so, point me in the right direction.

I've only had this truck a couple months. 175K miles. I've just had the TC and AT rebuilt. My problem is when the TC lockups at approx. 45-50MPH, if I try to hold that speed in traffic(just above lockup RPM) I get an obvious shutter or shimmy. If I decrease or increase RPMs it smooths out. If I turn off the OD it also runs smooth again at the higher RPM. I had this problem before the AT rebuild. I thought it was part of the wore out tranny. Guess not.

I've read the posts about the TC shifting back and forth, but I don't think my problem is the same (or is it?). I just got the gooseneck installed and used it to haul a Farmall 560 to a local plow day this weekend. For the first time, I also experienced the TC unlocking briefly as described by others. But my previous shutter problem is totally different than this event.

Sorry if this is a newby question. Is this shuttering at lockup something unique to me or is this the same shifting problem described by others dealing with the electrical interference of the TC locking and unlocking or a need for a new APPS? Any suggestions are appreciated. If I can figure this out, I've got this truck running strong and lookin' good!

SilverDollar

dozer12216

Did the tranny shop use ATF+4 or snake oil and dexron. No additives required for ATF+4. Did you upgrade the valve body??? or at least raise line pressure? It sounds like the radio interference I experienced. Just to test and humor me, wrap tin foil around the alternator positive (big one) cable to battery. Will require some unwrapping of wiring. Do not allow tin foil to actually touch a live terminal or will short. It does not have to be pretty to test. Also cover the PCM connectors at right side cowl... Let us know.

SilverDollar

Excuse my inexperience. What is the PCM, what does it look like, and is it right side sitting in driver's seat? I'm going to try this over the weekend. I read your other post. Can a simple resister on the alternator from NAPA do this same filtration?

Also, can ATF+4 be used in an early '99? Thanks for your reply.

j-fox

It sounds like it is fluid related. Knowing what fluid is in it may help.
Lube Guard sells an additive that makes the fluid a little more slippery, this ussually solves it.
Yes the ATF+4 is backward compatible.

morkable

I would say that to me it sounds like a bad tc. They will shudder when they go to lock up if the clutches are bad. It is possible it is just a bad one

Kevin

dozer12216

Behind the air cleaner. Three connectors into aluminum box.