Guys, two years ago i bought a 99 sub with 180000 miles on it. It has a new transmission and rebuilt transfer case. when i got home i changed all fluids. The rear diff fluid was definatly old but looked to still be okay. The front diff however came out like clumpy chocolate milk. I did a few flush runs and everything seemed to be okay. After awhile the front pinion seal started leaking. i popped the nut off and replaced the seal. Unfortionally i didnt mark where the nut was so i have no idea how tight to put it back on there. I set it to 150 ft/lb hoping i would be close. I believe after this is when we started noticing the whining/ mild growling only on decent with or without the brakes on. If you just let off the gas while you were going down the road you would hear this. Well i figured that maybe i didnt get it tight enough so i bumped it up to 180 ft/lb. It seems to be getting worse and worse. do you guys think that just getting a new crush sheeve will do the trick? Or does it point to a bad bearing?. i dont know alot about diffs so any help will be appriciated.
99 suburban front diff problem
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Update, i read somewhere that the torque value is supposed to be about 250 to 300 ft/lb so i tightened it to 250 and it is still growling and diff gets hot. It was recommended to me by a shop to try to replace the bearings and crush sleeve and tighten the nut until it takes 15 in/lb to turn the pinion. I think im going to try to do this myself. I believe while im in there im going to replace the seals as i do not want to do this again. Any suggestions or comments will be greatly appreciated.
That diff uses a crush sleeve. You must replace the crush sleeve if you take the nut off. This involves complete disassembly of the gears.
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You must remove the carrier and ring gear then the pinon gear. Replace the crush sleeve, Put the pinon back in, Put on the yoke. Tighten the nut untill theres no movement in the pinon bearings then you can put the carrier and ring gear back in.
No need to move any shims.
No need to move any shims.
the gears are already making noise, might as well replace the ring and pinion unless your markings are perfect.
You screwed up the crush sleeve. It is hard to get a resetup diff quiet .
Wel
Originally Posted By: bdcardinal
the gears are already making noise, might as well replace the ring and pinion unless your markings are perfect.
I was thinking that if they were in decent shape i would not like to spend a few hundred on new ones just becuase i probabaly wont use 4wd very often. i know the gears spin all the time but there is little pressure on them. i just want to get another 50 to 100 k miles out of it.
Originally Posted By: Steve S
You screwed up the crush sleeve. It is hard to get a resetup diff quiet .
When you say it is hard to resetup do you mean just tightning the bolt back or are you talking about actually pulling it apart and replacing the crush sleeve and bearings? Seems like if the gears are in good shape, it should go back together okay.
Originally Posted By: bdcardinal
the gears are already making noise, might as well replace the ring and pinion unless your markings are perfect.
I was thinking that if they were in decent shape i would not like to spend a few hundred on new ones just becuase i probabaly wont use 4wd very often. i know the gears spin all the time but there is little pressure on them. i just want to get another 50 to 100 k miles out of it.
Originally Posted By: Steve S
You screwed up the crush sleeve. It is hard to get a resetup diff quiet .
When you say it is hard to resetup do you mean just tightning the bolt back or are you talking about actually pulling it apart and replacing the crush sleeve and bearings? Seems like if the gears are in good shape, it should go back together okay.
If you are lucky, the pinion bearings are shot and can be replaced, and then it will be "good as new". If the pinion got loose enough to screw up the contact pattern, then a new ring&pinion will be required. Sometimes it is hard to differentiate between a gear whine and a pinion bearing purely by listening.
Changing a pinion seal doesn't require a new spacer. Mark the pinion and the yoke(I always had a bottle of "Liquid Paper" in my tool box). Zip the nut off, replace seal, zip the nut on and align your marks and it will be good to go.
With new bearings and crush sleeve, the torque on the pinion nut is secondary to the preload drag/torque on the assembled pinion. Hate to admit it, I did dozens and dozens of ring and pinions with 1/2" impact, and a dial torque wrench (in in/lbs). Once I hit 18-22in/lbs of drag with lubed new bearings I slapped the ring in , set backlash and shipped it. I can honestly say I never had a recheck on any ring&pinion replacement......ever.
It is always better to have slightly too much preload vs not enough in a new build.
Changing a pinion seal doesn't require a new spacer. Mark the pinion and the yoke(I always had a bottle of "Liquid Paper" in my tool box). Zip the nut off, replace seal, zip the nut on and align your marks and it will be good to go.
With new bearings and crush sleeve, the torque on the pinion nut is secondary to the preload drag/torque on the assembled pinion. Hate to admit it, I did dozens and dozens of ring and pinions with 1/2" impact, and a dial torque wrench (in in/lbs). Once I hit 18-22in/lbs of drag with lubed new bearings I slapped the ring in , set backlash and shipped it. I can honestly say I never had a recheck on any ring&pinion replacement......ever.
It is always better to have slightly too much preload vs not enough in a new build.
Well i picked up the diff today from the shop. The owner said it was a bad carrier bearing. He replaced all bearings and seals including outer seals and it cost me 380 dollars. 125 rebuilt kit, 50 outer seals, 180 labor , 8 dollar shop fee and taxes. Ill be putting it in tomorrow so ill post the results.
I put the diff in today and the truck still makes the same grinding sound upon decent. I dont know what it could be. The diff is not getting hot like it used to though. Anybody have any ideas. Im going to take both wheels off today and just inspect the brakes and stuff. How would you check to see if a wheel bearing is bad or not.
does your truck have a carrier bearing on the rear drive shaft?
i used to have one of these but i just dont recall, please let us know how its going for you.
i used to have one of these but i just dont recall, please let us know how its going for you.
Im not sure if it has a carrier bearing on the rear drive shaft. I have now located the problem. After putting the truck up on jack stands and putting it in gear so everything spins, I can defiantly hear racket from under the truck. i climbed under there and the x-fer case is grinding like crazy right behind where the front shaft goes into it. I drained a little fluid to see if there were alot of metal flakes in there and it did not seem as if there was. Would the bearing make alot of noise like that. it kind of sounds like loose gears on a shaft not meshing with something correctly. Again it does not do this all the time mainly upon deceleration and worse with braking but never during take off or shifting. I would think if it was a bearing it would do it all the time. On a good note, front diff is quiet as a mouse.
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