Driveshaft movement

[mikebGMC70]

I have a 70 c20 with a manual 4 speed. Having my 2 pieces drive shaft with the slip yoke on the carrier bearing balanced and mentioned to my driveline shop I’m bagging the truck and they mentioned the driveshafts might push in on the transmission or rear end to hard when going up or down with the bags. I figured only the driveshaft attached to the rear end would move in and out. Any thoughts on this? Thanks

[HO455]

This can be a problem with a coil spring C10 with the non splined rear drive shaft, but C20's should have a sliding splined joint in the rear half of the drive shaft. Any movement caused by the rear axle would be taken up there. On most C10's the entire drive shaft moves forward and aft as the axle goes up and down. Lowering one of these non splined drive shafts causes the drive shaft to be shoved forward where it could bottom out. It will also shorten the life of it's carrier bearing.

[mikebGMC70]

Originally Posted by HO455

This can be a problem with a coil spring C10 with the non splined rear drive shaft, but C20's should have a sliding splined joint in the rear half of the drive shaft. Any movement caused by the rear axle would be taken up there. On most C10's the entire drive shaft moves forward and aft as the axle goes up and down. Lowering one of these non splined drive shafts causes the drive shaft to be shoved forward where it could bottom out. It will also shorten the life of it's carrier bearing.

So this carrier bearing spline should be good to go with my bag setup?
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[HO455]

Yes it looks like it would work. As long as the carrier holds the shaft basic stationary forward and aft. I converted my bagged Burban to the splined style drive shaft with a billet carrier bearing as the original bearing rubber was blown out. I would do a check after you bag it to make sure the slider is not going to bottom out.
Air out the truck, remove the U-joint bolts at the axle and slide the drive shaft forward to make sure it isn't bottomed out.
Photo of the drive shaft I installed.

[mikebGMC70]

Originally Posted by HO455

Yes it looks like it would work. As long as the carrier holds the shaft basic stationary forward and aft. I converted my bagged Burban to the splined style drive shaft with a billet carrier bearing as the original bearing rubber was blown out. I would do a check after you bag it to make sure the slider is not going to bottom out.
Air out the truck, remove the U-joint bolts at the axle and slide the drive shaft forward to make sure it isn't bottomed out.
Photo of the drive shaft I installed.

My drive line guy cautioned me about the front shaft moving into the transmission but I cannot imagine that happening with it and the trans being attach to the frame.
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[HO455]

If the spline's bottom out it is possible for the shaft to be shoved into the transmission. Do the check to see if you still have clearance when the bags are aired out and the axle is on the stops. If so then it won't push the front shaft forward into the transmission.

[mikebGMC70]

Originally Posted by HO455

If the spline's bottom out it is possible for the shaft to be shoved into the transmission. Do the check to see if you still have clearance when the bags are aired out and the axle is on the stops. If so then it won't push the front shaft forward into the transmission.

I forgot to mention I swap rear ends and I’m having the driveshaft length changed. Thanks for the help.
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