What kind of grease should you use for the axle bearings on a 8 3/4? It's time to check mine and repack. tmm
Special grease for 8 3/4 axle bearings?
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mentor70
Well-Known Member
if you have the newer green bearings, they are sealed, no maintenance.
if they are OE bearings, they are lubed by the axle grease.
if they are OE bearings, they are lubed by the axle grease.
A383Wing
Well-Known Member
not true...there are seals inside and outside the bearings to keep dirt and rear end lubricant out of the tapered bearing....they must be packed with standard wheel bearing grease....
if yours are lubed by the rear axle lubricant, then you have a problem
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Actually, it's rear end 'oil' that's inside the rear end and even if the bearings see it....which they are not supposed to like A383 said, they will still live a good life but if it leaks past the outside seal, then the brakes will have a major problem. The axle seal (inner seal) is your best line of defense to keep the 80-90wt oil inside the housing as the outer seal is mainly to keep out dirt and brake dust.
747mopar
Well-Known Member
Here, in the pic you can clearly see what he's referring to. Notice the inner and outer seal separating the bearings from the gear oil.
http://hotrodreference.com/content/drivetrain/8.75moparrearend.jpg
http://hotrodreference.com/content/drivetrain/8.75moparrearend.jpg
toolmanmike, like posted already above just regular wheel bearing grease. I used napa brand 5 yrs ago and have had zero problems.
when putting the new seals in if you do not have the correct seal driver a short piece of 2" secd 40 PVC works great, you can feel the seal bottom out and not crush the outer collar.
when putting the new seals in if you do not have the correct seal driver a short piece of 2" secd 40 PVC works great, you can feel the seal bottom out and not crush the outer collar.
I had heard of some special grease that Mopar used initially but I didn't know if it would be an issue just to use the high temp grease that I use for the front. I have to be honest, I have been around Mopars since the late 60's and also thought they were lubed by the 80/90 from the diff. Thanks for the info. tmm
flyingfarley
Well-Known Member
I have been around Mopars since the mid 60's.....worked as a tech in a Dodge dealer in the late 60's and early 70's, and have never greased an 8 3/4 bearing that i installed! Always thought they were lubed by the 80w90 in the rearend! Never had any problems with the many bearings I have installed! Are you really supposed to grease them during installation?
At least I don't feel alone on this subject. My factory service manual doesn't say to pack the bearings but it does list a grease to use. I had this discussion on another forum and wondered what you guys thought.
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Yup, you're supposed to coat them with grease just like you do on the fronts. The inner seal is your damn so to speak to keep the oil off out of the bearings and from getting on the brakes. My first experience with rear end lube getting on the brakes was in 69 and is when I got schooled about what the inner and outer seals do. I didn't even know there was an outer seal but knew that the inner seal was in there and what it's main job was for....and it's about the time I started buying repair books lol
383man
Well-Known Member
Yes you need to pack them with wheel bearing grease. If you think about it the axle seal that goes in the axle tube housing keeps any diff oil from getting to the axle bearing on that setup and they have the small outer seal that keeps the wheel bearing grease in the axle bearings and from leaking out on the brakes. Most rears that do lube the axle bearings are the kind that use C-clips to hold the axle's in as on them the bearing goes in the housing first and then the axle seal goes in last so the diff lube can run down the tube and get on the bearing before the seal stops the lube. There are alot of the axle bearings on 8-3/4 rears that did not get the grease in them like they should have and I am surprised I have not seen more go bad over the years. Ron
Gunner75
Member
Toolmanmike. Hope you don't mind if I piggy back your post. I'm curious about this as well. Just dropped my 8 3/4 off at my buddies shop for teardown and part order. Complete overhaul. (out of 1970 Roadrunner)
My buddy decided he and another would go ahead and assemble without me present. Long story short he is supposed to swing by so we can go over everything. Until then, I'll add to your questions in preparation for his visit.
1st question is what they did for the wheel bearings. Pack them or not???
2nd question is regarding the RH axle and it's adjustment. When I pulled the axle I noticed it felt like the RH shaft wheel/axle bearing was toast. Lot's of up and down movement. Yes the side with the adjuster. Upon my inspection of the rear axle assembly I decided to get a feel for the side to side adjustment and to also go ahead and see if there was still up and down. There is, doesn't feel as much, but it steel feels excessive. I'm gonna tear it down and check it out pending the info on here and what he reports.
My buddy decided he and another would go ahead and assemble without me present. Long story short he is supposed to swing by so we can go over everything. Until then, I'll add to your questions in preparation for his visit.
1st question is what they did for the wheel bearings. Pack them or not???
2nd question is regarding the RH axle and it's adjustment. When I pulled the axle I noticed it felt like the RH shaft wheel/axle bearing was toast. Lot's of up and down movement. Yes the side with the adjuster. Upon my inspection of the rear axle assembly I decided to get a feel for the side to side adjustment and to also go ahead and see if there was still up and down. There is, doesn't feel as much, but it steel feels excessive. I'm gonna tear it down and check it out pending the info on here and what he reports.
I use Mobile red syn. grease for everything. Auto Zone stocks it.
Other places may have green Valvoline.
I've cleaned and repacked 8 3/4 bearings and not had to cut and remove them.
Put the axel over a catch tray and wash with mineral spirits till clean.
Then pack.
When I worked plant mtc. I read an article that pointed out that synthetic is more expensive but you only have to have one kind of grease then.
It is high temp, extreme pressure and water proof.
It is also fully compatible with other greases.
Mixing grease stocks can cause problems.
Off topic but from my experience on A/C Boeing uses green syn.
(Expect on brakes.)
M/D uses red syn.
.
Other places may have green Valvoline.
I've cleaned and repacked 8 3/4 bearings and not had to cut and remove them.
Put the axel over a catch tray and wash with mineral spirits till clean.
Then pack.
When I worked plant mtc. I read an article that pointed out that synthetic is more expensive but you only have to have one kind of grease then.
It is high temp, extreme pressure and water proof.
It is also fully compatible with other greases.
Mixing grease stocks can cause problems.
Off topic but from my experience on A/C Boeing uses green syn.
(Expect on brakes.)
M/D uses red syn.
.
747mopar
Well-Known Member
I'll see if I can't find a pic for you but here's how it works, the one axle adjuster adjust both sides via a pin that extends threw the center of the carrier making it possible for the preload adjustment to takeup both sides (make sure that pin is in there). Adjustment is very easy, crank it in tight smacking the axles with a soft hammer to insure bearings are seated then back it back off. Now smack the axles again to create play, put a dial indicator on the axle flange and adjust until the end play is in spec (.008"-.018").
I did a thread on changing out my gears and it has some useful pics in it so you can check it out.
http://www.forbbodiesonly.com/moparforum/showthread.php?91305-Rebuilding-an-8-3-4-489-sure-grip-differential
- - - Updated - - -
Post #8 shows the pin.
Gunner75
Member
727Mopar I actually found your post earlier and your description of assembly is pretty much what I read in the manual and elsewhere. I'll get it pulled down and inspected. (as well as speak to my buddy that took the liberty to assemble with me not present, LOL). Thanks. A little more detailed picture than the manual.
- - - Updated - - -
Couldn't help it, ran back out to the shop and I pulled the passenger axle assembly out. My buddy did pack the bearings. A quick measurement on my axle housing and bearing cup have me worried. He installed the the Auburn limited slip as I selected that unit for this car. I can see the cross bolt pin that transfers preload. I'm gonna go ahead and pull the other axle to check R&L housing where the races run to ensure the last bearing didn't spin it large. It doesn't look too good to be honest. I came up with about .050" larger housing than bearing race but that was a quick measurement. It felt more like .150 or better assembled so I will assume they didn't have the preload just right. Thanks fellas.
- - - Updated - - -
Couldn't help it, ran back out to the shop and I pulled the passenger axle assembly out. My buddy did pack the bearings. A quick measurement on my axle housing and bearing cup have me worried. He installed the the Auburn limited slip as I selected that unit for this car. I can see the cross bolt pin that transfers preload. I'm gonna go ahead and pull the other axle to check R&L housing where the races run to ensure the last bearing didn't spin it large. It doesn't look too good to be honest. I came up with about .050" larger housing than bearing race but that was a quick measurement. It felt more like .150 or better assembled so I will assume they didn't have the preload just right. Thanks fellas.
No problem Gunner. I wanted to bring up the subject because of the amount of people that didn't know they needed grease. tmm
GassMann
Well-Known Member
I just finished installing a slip diff in my axel housing but never noticed the adjuster on the right hand side. After reading this thread, noticed the adjuster in the drawings.
I know this is an old thread but can anyone tell me what the right hand "adjuster" is supposed to do and how to adjust it?
Tapered axle bearings or Green bearings? The stock tapered bearings has a thrust button between the axles and the adjuster sets the axle end play.
FJ5 Road Runner
Well-Known Member
Before removing the axles,I usually put a dab of paint on the adjuster ring where the retaining washer was engaged.That way when you put it back together,the old adjustment should get you real close or right where you need to be for the end play adjustment.
Also,when greasing the rear wheel bearings,you want to make sure you get plenty of grease into every bit of the bearing.I have a hand pump grease gun that I keep a rubber tipped fitting on the end of that I press onto the areas of the bearing shell between the rollers and pump it full in each spot.
It's a good plan to replace the inner oil seals if they're old and have hardened over the years.Running old hard seals will wear a groove into the axle shaft where the seal makes contact and when that happens,you'll have a leak that's almost impossible to stop even with new seals.
Another tip: the sharp splines on the end of the axle shafts can damage the inner oil seal when they go through them so only pull the axle shafts out part way to re-grease the bearing to avoid tempting fate.If you do have to pull the axle seals out,cut an empty toilet paper roll lengthwise then wrap it around the splines when inserting them through the seal then pull the roll off when the splines are clear.
Also,when greasing the rear wheel bearings,you want to make sure you get plenty of grease into every bit of the bearing.I have a hand pump grease gun that I keep a rubber tipped fitting on the end of that I press onto the areas of the bearing shell between the rollers and pump it full in each spot.
It's a good plan to replace the inner oil seals if they're old and have hardened over the years.Running old hard seals will wear a groove into the axle shaft where the seal makes contact and when that happens,you'll have a leak that's almost impossible to stop even with new seals.
Another tip: the sharp splines on the end of the axle shafts can damage the inner oil seal when they go through them so only pull the axle shafts out part way to re-grease the bearing to avoid tempting fate.If you do have to pull the axle seals out,cut an empty toilet paper roll lengthwise then wrap it around the splines when inserting them through the seal then pull the roll off when the splines are clear.
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