'86 F250 4x4 351w
I just got the motor rebuilt yesterday. Now I have a new problem.
There is a noise coming from the drive train. It sounds like an aluminum can rattling when the truck warms up and during mild acceleration.
Would a bad U joint make this sound?
Is there any reason the Transcase would make this sound in 2wd.
Is anything in the Transcase moving if the truck is in 2wd and the hubs are free?
Any other suggestions?
BTW, this existed before the rebuild. I just thought it might be engine related and had other problems to worry about.

Thanks,
ScottyB.

 

If you have a bad u-joint you'd probably feel it before you hear it. It would cause the shaft or axle to be off center or wobble. Since you say it happens after the engine warms up, I doubt it would be the drive train.

As for the transfer case, yes, stuff is moving when in 2wd. It's possible that the noise could be from there. I had a similar noise in my tractor. It turned out to be a bent fork in the transmission that wasn't seperating the gears all the way. Whenever I'd slow down, the one gear would slide forward and lightly touch the other and bounce off (making the tin can sound). I don't know which t-case you have so I don't know if this is what it could be.

I would first look for simple stuff like a heat shield somewhere on the exhaust system. Given the circumstances, that seems likely.

Does it do it while you're sitting still? Does it increase/decrease with engin speed? What about with vehicle speed?

Kevin K.

 

It may be something wrong with the motor itself. Does the rattling happen only when in gear or does it happen when your in neutral and park?

 

Thanks for the reply.
It doesn't do it while sitting still.
It is loudest when accelerating (30-50mph), when there is medium torque but not HEAVY torque.
I will check out some more obvious things like brackets, sheilds tonight.

I am caution about transfer cases since I had one blow up on me at 60mph. That was not nice.
The front drive shaft hit the road, then came up through the floor board, wiping out gas lines on the way, resulting in a HUGE fire ball that engulfed the truck (with me in it). I got out and ran my ash off.
That time it was a howling sound before the incident.
I was told that one of my hubs was locked without my knowledge.
What a mess.

This was the second Chevy that Flamed on me. That is why I am on THIS forum.

Later,
ScottyB.