Ive had a metallic clunk in the drivline of this truck when shifting into Reverse for a while. I dont drive it much, and its got almost 300k, so I just dismissed it as an internal 4l60e issue that I was gonna just ride out until it something caused me to pull the tranny. If I quickly bypass Reverse to go to Drive, no clunk. But stopping the shift lever in Reverse produces the clunk.
Yesterday, I crawled under it to change the T case fluid, and I noticed that I think the noise is actually coming from the front drive shaft output area of the T case. I could duplicate the noise by trying to rotate the front driveshaft. To my surpise, the front driveshaft seems to be engaged, even though the truck is in 2H. Im not sure, but I think some GM trucks of this vintage are designed to have the front driveshaft rotating all the time so I dont know if that is indicitive of any issue. The front drive shaft has about 3/4" of rotational play. Not sure if that play is from front diff slop or Tcase slop. Not sure if its supposed to be rock solid tight like the rear is.
All U joints, front and back appear tight with no play. If I jack up a front wheel, they turn independently in 2H. If I jack up a wheel in 4H, you can tell its engaged, and I can also duplicate the clunk by trying to turn a front wheel.
The previous fluid was at the appropriate level and still bluish. Ive done some reading about these auto systems sticking in either 2wd or 4wd. Next week it is going on a lift and Im gonna thorougly put the 4wd through its paces. Hopefully I can get a scanner to see if Tcase engagment motor is working properly. Any thoughts?
Yesterday, I crawled under it to change the T case fluid, and I noticed that I think the noise is actually coming from the front drive shaft output area of the T case. I could duplicate the noise by trying to rotate the front driveshaft. To my surpise, the front driveshaft seems to be engaged, even though the truck is in 2H. Im not sure, but I think some GM trucks of this vintage are designed to have the front driveshaft rotating all the time so I dont know if that is indicitive of any issue. The front drive shaft has about 3/4" of rotational play. Not sure if that play is from front diff slop or Tcase slop. Not sure if its supposed to be rock solid tight like the rear is.
All U joints, front and back appear tight with no play. If I jack up a front wheel, they turn independently in 2H. If I jack up a wheel in 4H, you can tell its engaged, and I can also duplicate the clunk by trying to turn a front wheel.
The previous fluid was at the appropriate level and still bluish. Ive done some reading about these auto systems sticking in either 2wd or 4wd. Next week it is going on a lift and Im gonna thorougly put the 4wd through its paces. Hopefully I can get a scanner to see if Tcase engagment motor is working properly. Any thoughts?