Transmission Expert Needed

[BillK]

While slowly crawling up the on ramp to the freeway, I experienced an abrupt clunk like someone had run in to the back of my truck. Looking back, I didn't see anyone. It happened again a few seconds later.

The transmission shifts fine other than that. It's a little smooth on the shifts, but no apparent slipping. It seems like the torque converter may be locking up while I'm crawling real slow. Any transmission experts out there?

[Uncle Wally]

The first step is to pull codes to see what if anything is going wrong with the electronic controls/sensors.

Waldo

[rameye]

Mine did that twice..coming to a stop and then accelerating from a stop..then the torque converter blew.

Sometimes u-joints will clunk.

No expert here..hope it helps

[RumRunneR]

Heres one for ya, I changed a bad wastegate solenoid and now it seems the transmission is shifting differently. Sometimes it won't shift from 2nd to 3rd and will redline if I don't tap on the throttle. Changing the fluid and filter didn't seem to make a difference.

[BillK]

Definitely not U-Joints--sounded like someone ran in to my truck. Not a clunk. Only code thrown since I replaced IP is a wastegate solenoid (78) temporarily while I was accelerating up a long hill.

[Uncle Wally]

Depending on where the thunk came from, I would pull the torque converter inspection cover and make sure all is well there. No broken bolts or flex plate. I would also check to see if the motor mounts are obviously coming apart.

I know my truck does this every once in a while. But it's from the down pipe hitting the bottom of the cab. I installed JK's exhaust and the sandwiched seam at the leading edge of the cab hits the downpipe every now and again. That should be fixed soon.

Waldo

[autocrosser]

Have you tried shifting your trnasfer case. My son had a similar problem recently and it turned out to be a broken shift fork on the transfer case. He found it out when he tried to shift into 4wd.