Ok, so I'm opening up the rear diff to inspect it before my trip to NC. I don't want to tow a trailer all the way there without checking it out. I've got a little noise coming from the rear end (I think) whenever I go from park to drive/reverse. What are some things to look for besides chewed up gears?
Opening up the rear diff....
tasnat23
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Ok, so I'm opening up the rear diff to inspect it before my trip to NC. I don't want to tow a trailer all the way there without checking it out. I've got a little noise coming from the rear end (I think) whenever I go from park to drive/reverse. What are some things to look for besides chewed up gears?
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2,437 Posts
Before you open it up put it in neutral with the brake on and wheels chocked to check your u-joints. Then you can drop the driveshaft and check the pinion nut....put a torque wrench on that baby and get it up to at least 150 lb/ft, better yet try for about 170.....I can't remember the exact spec but you probably can't get much more than that with an ordinary torque wrench.
If all that checks out get a dial indicator so you can check the lash when you pull the cover. It should be around 8 to 13 thousandths. Look on you tube.
Don't forget the proper sealer for the cover either.
Setting the lash is easy, all you need is a 5/16 socket to remove the lash adjuster locks and a good drift or punch with a hammer to turn the adjusters. Don't be afraid to put a little pre-load pressure on the diff carrier bearings either.....because you probably don't have any right now. Triple check the lash to ensure it's not too much!
If you can't get a dial indicator you can still add some pre-load to the carrier bearings by moving both adjusters the same number of holes.....Left one going down, right one going up. Once again, I'm willing to bet the pre-load is gone. Mine was literally chunking from side to side a few thousandths, which will cause noise. Those bearings have to be pretty tight!
You may have some metal filings on the drain plug, which is ok as long as it's only some. Also crack your fill plug first to ensure it's working.
If all that checks out get a dial indicator so you can check the lash when you pull the cover. It should be around 8 to 13 thousandths. Look on you tube.
Don't forget the proper sealer for the cover either.
Setting the lash is easy, all you need is a 5/16 socket to remove the lash adjuster locks and a good drift or punch with a hammer to turn the adjusters. Don't be afraid to put a little pre-load pressure on the diff carrier bearings either.....because you probably don't have any right now. Triple check the lash to ensure it's not too much!
If you can't get a dial indicator you can still add some pre-load to the carrier bearings by moving both adjusters the same number of holes.....Left one going down, right one going up. Once again, I'm willing to bet the pre-load is gone. Mine was literally chunking from side to side a few thousandths, which will cause noise. Those bearings have to be pretty tight!
You may have some metal filings on the drain plug, which is ok as long as it's only some. Also crack your fill plug first to ensure it's working.
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5,352 Posts
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2,437 Posts
Have you tried putting it in neutral with the brake on and wiggling things around on the driveshaft at the rear axle yoke yet? If that yoke slops around even a little bit you should get new bearings, a seal, and a crush collar......or your pinion nut is loose, that's been known to happen.
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403 Posts
OP- maybe a trans mount issue?
Lubecakes- slight tangent... I have my rear axle 90% apart, to replace the e-locker (destroyed spiders), but have not removed the bearing caps to remove the carrier yet. The new e-locker will be here next week. When I remove the old carrier, will I have to move the adjusters, or do they stay in place while the carrier comes out? If they have to be removed, or adjusted, should I mark their original orientation?
Lubecakes- slight tangent... I have my rear axle 90% apart, to replace the e-locker (destroyed spiders), but have not removed the bearing caps to remove the carrier yet. The new e-locker will be here next week. When I remove the old carrier, will I have to move the adjusters, or do they stay in place while the carrier comes out? If they have to be removed, or adjusted, should I mark their original orientation?
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2,437 Posts
Yes.
No.
Mark up, down, left, and right on the bearing caps, they must go back the way they were.
Your backlash will have to be reset. This means you'll be moving those adjusters around to achieve that. You'll need a dial indicator and the knowledge of how to use it, as this setting is extremely critical.
You must also have the proper preload on the pinion and carrier bearings, especially if you're replacing them. Are you replacing the bearings?
If I get time tonight or tomorrow maybe I'll do a DIY write up on the entire process of replacing the bearings.
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403 Posts
I have measured the backlash (with dial gauge) with the axle shafts removed, I will be replacing the carrier, with a new (4 pinion) e-locker, with new carrier bearings, and I have already marked the bearing caps for orientation/location. I am using the original ring/pinion, and will not be messing with the pinion at all. Thanks for your input! Any other info on setting preload would be great.
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1,254 Posts
Side gear back clearance 0.305 (0.0120) or less.
Drive pinion bearing preload torque 1.7 - 3.8
Drive gear to drive pinion gear 0.08 - 0.13.
Got this info from a pdf I downloaded before my tru-trac install.
Drive pinion bearing preload torque 1.7 - 3.8
Drive gear to drive pinion gear 0.08 - 0.13.
Got this info from a pdf I downloaded before my tru-trac install.
Ok so I dug into it today. I checked my pinion nut.... Tight. Rear u-joints.... Tight. Gears, looked perfectly fine. I did tighten the adjusters one hole. Seems a little better. Doesn't feel like it shifts hard and clunks going from park to reverse or drive. I have about .008-.010 worth of backlash now. Before it was like .015-.020. So we will see how this works.
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