Summary

Problem:Vibrations in the drivetrain
My previous thread

U-joint at the back replaced
Tranny flushed, magnet cleaned, new oil
Extension Housing and bushing replaced
SlipYoke greased

01-31-2003
U-joint at the front replaced.

When I got home from replacing the front U-joint the truck started driving worse and worser.
Problem has never been that bad before.
I don't think the driveshaft is out of balance but who knows.
It is the first thing I am going to check now.

But it's really odd that the problem is getting worse when the engine warms up.
I was thinking on a Torque Convertor shudder.
I have read this article.

TC Shudder

***

I have always thought that my engine was the problem while it was running rough although at idle it was at a steady 600 rpm.
Also when I lay my hand on either side of the box just above the taillights I can feel the truck shudder slightly.

Could it be I have a bad torque convertor or maybe the TC is out of balance or something.

What could possibly wrong with a torque convertor?

TIA

 

I don't think it's the torque converter.

Considering that you think the vibration increased after the front U-joint was replaced, the driveshaft may be out of balance with the rest of the driveline. I don't think you need to have it balanced, but rather just have it indexed to cancel out the vibrations. The driveshaft, transmission output shaft and rear end all create a vibration, or oscillate. The driveshaft/transmission output shaft/companion flange all need to be indexed to cancel each other out. Basically, so that everything vibrates at opposite frequencies instead of together.

There is a good possibility that when they removed and reinstalled the slip yoke, that it was not indexed on the output shaft. There should be paint marks on both, as well as at the companion flange that all line up.

It is also possible that when the extension housing was replaced, they changed the driveline angle at the transmission mount, (raising or lowering the transmission) therefore changing the angle and creating a vibration.

You should also have the exhaust system neutralized. I'd say there is a high likelihood that this is contributing to the vibration you feel when you touch the bed. To neutralize the exhaust, you simply loosen all of the exhaust bolts (from the cats on back) and drive your truck until the entire system reaches normal operating temp. Also spray a penetrating oil into the exhaust pipe connections to help loosen them. It's important to actually drive the truck rather that just letting it warm up in your driveway because the vibrations will change as you go through the gear shifts (it will make all sorts of strange noises too). Then come home and retighten all of the bolts.

As a side note: I neutralized my exhaust last week and completely cured a vibration I've had at 55mph-62mph for years. I always thought it was something between the engine and differential because it only happened at those speeds, never in part or nuetral. Turns out it was the exhaust system.

You may also want to consider that you are getting an intermittent misfire at just one cylinder.

 

Thanks for your reply.
I will check everything you mentioned.

"There is a good possibility that when they removed and reinstalled the slip yoke, that it was not indexed on the output shaft. There should be paint marks on both, as well as at the companion flange that all line up."

They did index it, they put markers on.


"It is also possible that when the extension housing was replaced, they changed the driveline angle at the transmission mount, (raising or lowering the transmission) therefore changing the angle and creating a vibration."

The extension housing was replaced more than a week before the front U-joint was replaced.
I didn't have the problems I am having now back then.
Things went real bad when they replaced the front U-joint.
They did put markers there on as well.

I don't think it is the exhaust.
I would be really surprised when that would be the problem.

What really wonders me is why it's getting worse when the engine is getting warmer.
Also, when it is under load problem is worse.
Freewheeling, problem is less but still there and when I step on the gas again, engine is under load again problem is getting worse again.

Engine miss

Engine has been checked twice so far and everything is fine, so they say.
Vibrations on idle in drive are much less (under load) as idling in Neutral however.
I am no mechanic however on the contrary but I am still thinking about a problem with the TC.

I am looking for clues on this so If you guys would me,
it would be much appreciated.
Any suggestions are welcome.

CJ

ps
After replacing the front U-joint, the mechanic and I did a testdrive.
Me sitting on the passengerside didn,t notice an improvement.
When I drove home and the engine warming up real good (probably) problem got worse and worser.