Two piece driveshaft
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Cargo Master
Joined: Jul 2006
Posts: 3,014
Likes: 91
From: Concord, CA
Two piece driveshaft
A few weeks ago I took out my driveshaft and brought it down to have the u-joints replaced and the whole thing balanced. Well I get it back and put it in but ended up with the sound of metal turing inside metal. This is most obvious when in reverse or coasting in drive but never when on the gas in drive. After going through section by section the noise has been coming from the center bearing. Should have heard it when I removed the second section and then started the truck. No sounds until I put it in reverse and boy did it whine with that metal scrapping sound. Obviously it is going back to the shop for them to diagnose the problem now that I isolated it but what could it be? A bad new center bearing compared to the old. Can't see how it is alignment given the easy task of lining up arrows on the shafts and the bearing holder only has a about a 1/16" of play left to right.
Postmaster
Joined: Dec 1999
Posts: 2,813
Likes: 6
From: Connecticut
It's possible that the new bearing is bad. It may be twisting as you back up. Was there any shims under the plate when you pulled the shaft out. These are crucial to the pinion angle . Not all the trucks had them. Make sure the bearing is aligned or square on the mounting bracket. Go back and have them listen and hear the noise.
Barry
Barry
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Cargo Master
Joined: Jul 2006
Posts: 3,014
Likes: 91
From: Concord, CA
Problem solved. After bringing the first half of the shaft back in a experienced eye saw something right off the bat. One of the tabs that holds the bearing assembly in place (bottom one) showed signs of scoring. This meant the the drive shaft was lower at the transmission end than the center bearing and the tab hit a flange. How? Had to replace the transmission mount as it was splitting in two. Apparently the new mount is a tad shorter than the original as there were no shims previously. So what to do since the new mount can't have a shim put under it given the bolt that passes through it. Most likely put a one piece shim under the center bearing or try another manufacturer for a rear tranny mount. Hmmm...
Now that I thought more on it in my head I realize that the shaft is high at the tranny and lower at the center bearing to enable the 6 o/c tab to hit. So a shim above the center bearing won't work as I need to go higher. So it looks like a different mount...
Now that I thought more on it in my head I realize that the shaft is high at the tranny and lower at the center bearing to enable the 6 o/c tab to hit. So a shim above the center bearing won't work as I need to go higher. So it looks like a different mount...
Last edited by tbm3fan; Sep 28, 2006 at 02:37 PM.
