Changed driveshaft on 2003 Silverado 1500 Ext. Cab base - issues

[Digger02]

Hey,

 

I broke my driveshaft on a big rock on a hillside out in the woods on my 2003 Silverado - I got the truck stuck, gave it gas, and the rock basically machined a groove through the aluminum-tube shaft, and shreaded the foam inside the shaft. The shaft got torn up pretty good.

 

I got a junkyard driveshaft that looked good - no dents, no signs that welded-weights had fallen off, and headed out to the woods to do a swap last night. The caps on the universal joint at the back end of the shaft rolled smoothly.

 

Couple of questions:

 

1) I could see that that the front yoke had a wide flat on the inside where there was a missing tooth on the inside spline - I couldn't see a matching place on the shaft coming out of the transfer case where there was a wide flat, but it was getting dark. Is there one? Would the shaft even slip on if it wasn't lined up correctly? I was able to the slide the shaft in without too much difficulty, and topped off the transfer case with Dexron III. I had lined the replacement shaft up with basically the same orientation as the broken one I took off.

 

For the bolts on the back universal strap, I hand tightened them down with an fairly small 11mm wrench. Should these be cinched down as tight as they can go, or does that put too much stress on the needle bearings inside the universal cups. Needless to say, I didn't have a torque wrench. Is a little looser on the rear universal strap bolts better for those needle bearings?

 

I drove the truck out with no problems, but when I got out on a smooth flat road, I could feel a vibration when I got over 50mph. I can't tell if its coming from the front or back of the rear driveshaft.

 

I was going to play with it more tonight or this weekend, but wanted to see what you all thought.

 

Thanks,

 

Dave

[jaredlucky16]

driveshaft may need to be balance. I just snug them up pretty good with a wrench and my hand you should be alright

[Digger02]

Thanks - I pulled the driveshaft in the driveway with a bright light, and there's definitely no notched area on the spline coming out of the transfer case. I put some bearing grease on inside the yoke, did a better job centering the rear universal caps under the straps, tighted the straps down, and she runs smooth and vibration free up to 85mph (this testing performed by professional drivers on a closed course - do not attempt this driving yourself).

 

Dave