Driveline noise ?

[kick]

My 1990 V10 Blazer with 700R4 has a noise coming from the extension case front u-joint area on the rear driveshaft. It seemed to be the u-joint so I replaced both on the rear driveshaft. The problem still exists on medium to quick starts in both drive and reverse. It does not happen all the time. I will check the splines on the output and input shafts again as they seemed fine. It seems like something is under pressure. The truck runs fine there is no vibration. When this noise occurs from a dead stop it seems to be mid truck more to the passenger side. Any ideas what this could be ? Thanks Charlie

 

[ugly_blazer]

What does the noise sound like? Does it change as you speed up or slow down?

 

[kick]

The sound just happens once either in Drive or Reverse. It does not happen all the time. Only from a dead stop.

 

[ugly_blazer]

Is it a "clunk" noise? Only happens once when you put it in gear?

 

[backcountry]

Have you recently done any recent modifications?

Check your u-bolts and make sure they are torqued to spec.

/forums/images/graemlins/peace.gif

 

[kick]

No it is stock the bolt a torqued correctly. I'm thinking its got something to do with the output shaft.

 

[kick]

No the noise only happens on takeoff. I can go back and forth to Drive and Reverse with my foot on the brake and reving the motor with no driveline noise. This is a strange one.

 

[ugly_blazer]

/forums/images/graemlins/dunno.gif

 

[big jimmy 91]

Is it a single clunk?
I have it on my truck also but it goes bang bang bang repeatedly until you are moving
It is the t case hitting the floor pan due to a broken torsion bar from the motor to t case and weak mounts
Mabey that is happening with your truck /forums/images/graemlins/thinking.gif

 

[kick]

Yes that sounds good. I will check the mount it seems ok but it is OE and 15 years old. But it maybe bad as I can only apply so much force lying on my back. Thanks I will check it tomorrow,

 

[kick]

It was a transmission mount starting to go. Thanks all