I have a '99 2500 4x4 w/auto trans that "bucks" at highway speeds & pulling grades (6%) . Bucking is intermittent & doesn't change w/ speed. Truck has 150,000 mi on it & about 20,000 on new trans. Have had it to dealer twice but they can't find problem & can't get it to do it when they test drive. It has been doing this for probably 6 months now. Recently it developed a small leak on top of fuel filter housing, and dealer wanted 1300.00 to replace it, I said no but am wondering if this is connected to other problem. Any ideas? Thanks>>>----> Jed

 

Welcome to DTR

You may have a TC (torque converter) slipping. Look at the simple stuff first. Check fluid levels.

What was leaking?

 

Fluids are fine, Diesel fuel leak from rubber grommet on top of housing with two wires running through it. Dealer said this was a common problem & replacement housing thry wanted to put on was an updated version, but I told them it could leak for a long time before it used up 1300 worth of fuel. Surely there is an easy fix for alot less. thanks

 

I'll tell you exactly what it is.... your lift pump is croaking.

Before all my goodies went on the truck I experienced the same thing while towing. It isn't a really jerking buck, but rather a little hiccup. I knew right away that it was the lift pump and had it replaced under warranty. Would you guys believe that my VP lived for almost 75K miles after that!?

Anyway.... tell your dealer to check the lift pump if you must take it there, but based on them trying to tell you it would be $1300 for the little fuel filter problem I would find somewhere else to spend my money.

 

If you really want you can have my old housing for the shipping costs. I took it off when I installed my FASS.

 

Smokindog, I originally thought lift pump was culprit & it was bad, had lift pump retro kit installed in oct. but it didn't cure problem. Thanks for offer of housing but I'm sure there's gotta be an easier solution. Like your quote!

 

Sounds like what I was experiencing when my TPS/APPS was out of adjustment. It would lock and unlock the torque converter and occasionally shift gears back and forth if at just the right speed. I adjusted the APPS to as close to .574vdc as I could get it and and followed the instructions on resetting it (disconnect batteries) and it has been fine ever since (several months).

HTH

 

Mine did the same thing -- replaced the IP about 10k miles ago and running great ever since