Neverdone

Hey guys, here is my current issue:

On acceleration from dead stop, I get a brief surge/pulse. Seems to happen between 5-15 mph then quits. As far as I can remember it has done this, but it was barely noticeable. As of recently it has gotten a lot worse where everyone notices. The surge/pulse is very similar in feeling to braking with warped rotors accept it is under acceleration. It does not seem to matter what gear I am in as I have tried it in both first and second with the same results.

This increased surge/pulse also coincides with a high speed vibration which is entirely new. Seems to be noticeable between 62 and 75 mph in overdrive. Didn't think to down shift to see the results.

All this came about after a weekend of towing a trailer weighing approx. 3500 lbs. I have a transmission cooler and have bumped my line pressures slightly to compensate for a slipping 4/3-2 down shift. (Been running with this tune for years, so I doubt this issue is related).

So my question, does this sound like a TC going south? Transmission? U-joints maybe? I plan on replacing the u-joints, and changing the transmission filter and oil on Wednesday when I am off work(I get parts cheap and want to do this anyways). Transmission has 70000 miles on it.

What are your thoughts? Need to get this figured out before I go on vacation, would hate to have to leave the truck at home.

Gregg Nader

The surge/pulse is very similar in feeling to braking with warped rotors accept it is under acceleration.

This sounds like either tight rear U-joint (must remove shaft to verify), loose U-joint, bad trans mount or U-joint angle. Is the ride height stock? If lower, this will affect U-joint angles.

Gregg

Circle-D

iTrader: (21)

Check to see if the vibration is there in park. That will check to see if it is driveline vibration or a converter. It could also be something going wrong with the lock up clutch, but not likely at 5 MPH.

Chris

Neverdone

Truck is lowered 2/2 currently, u joint/pinion angle should not be an issue. I will check the trans mount and u-joints first.

I'll definitely check this when I get back to town, thanks for the tip Chris!

Neverdone

FYI, it was a combination of tight u-joints and a worn steady bearing.

Circle-D

iTrader: (21)

Glad you got it figured out!!

Chris