1998 suburban 2500 drivetrain noises

[Eddie7644]

I have a 2500 with a 4l80e and when your going slow speeds you can hear a clanking noise like a bad ujoint. Put it on Jack stands and put it in gear sounds like it’s coming from the transfer case but only does it at low speeds. Any ideas?

 

[bigfootchiro]

Does the noise sound rotational/consistent?

 

[Eddie7644]

Yea actually sounds like a blown rear. But only in parking lot speeds

 

[Bill 1960]

Could be a loose chain slapping. Or it could be telegraphing the sound from the rear to the tcase. I usually put them up on jack stands and start spinning things by hand to listen for the source. If that doesn’t help I start removing driveshafts and test driving with only RWD or FWD to isolate.

Happy hunting!

 

[drakon543]

is this a 4wd version? if so put it in 4wd and see if the noise stops. if it does remove the drive shaft remove the transfer case tail and look for pieces of a what could have been a snap ring sitting in the tail housing. im not 100% here but exact thing happened to me with a 94 2500 suburban. if there is a snap ring supposed to be there it could have broken. higher speeds and or just driving straight mine was quiet. it was also quiet when 4wd was engaged. buddy at a gm shop suggested i check there and sure enough that was my problem.

 

[Eddie7644]

Drakon543 Yeah there is no noise when in 4wd only in 2wd. Like I said once I get out of the parking lot onto a road it’s quiet lol. So sounds like exactly the same thing you had. Which snap ring was it that broke?

 

[OR VietVet]

Sounds like chain slap from being stretched and sloppy, or was that an old girlfriend I knew once? Let me think on that.

 

[drakon543]

Drakon543 Yeah there is no noise when in 4wd only in 2wd. Like I said once I get out of the parking lot onto a road it’s quiet lol. So sounds like exactly the same thing you had. Which snap ring was it that broke?

rear output shaft snap ring. its supposed to hold the shaft in place when they break the shaft likes to walk when it doesn't have an actual load on it and it binds internally.

 

[drakon543]

hit post too soon
if its supposed to be there on your xfer case you will see the remnants if you pop off the output shaft tail housing. they are crazy snap ring and not fun to replace.

 

[Eddie7644]

Am I able to do it with it in the truck still or does the case have to come off the trans?