Differential Preload

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sbh126

sbh126

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first off this is a 489 case. I'm putting my differential back together but I'm not sure how tight it all needs to be. I installed a solid spacer and torqued the pinion down to 125 in lb per the instructions. But if I use the shims that came with the spacer, I cant get the bearings to seat. I removed all the spacers and tightened it down and got it to seat but I'm not sure if its to tight or lose. When I spin the pinion it will rotate without much effort but it wont continue to spin when I let go. Is that about right? I know thats kinda vague. I broke my in lb torque wrench and am trying to get the job done with out it.
Also How tight do the bearings that hold the ring gear need to be?
 
sbh126 said:
first off this is a 489 case. I'm putting my differential back together but I'm not sure how tight it all needs to be. I installed a solid spacer and torqued the pinion down to 125 in lb per the instructions. But if I use the shims that came with the spacer, I cant get the bearings to seat. I removed all the spacers and tightened it down and got it to seat but I'm not sure if its to tight or lose. When I spin the pinion it will rotate without much effort but it wont continue to spin when I let go. Is that about right? I know thats kinda vague. I broke my in lb torque wrench and am trying to get the job done with out it.
Also How tight do the bearings that hold the ring gear need to be?
Click to expand...

my 2 cents, you need to sneak up on the preload. Can't really go from one extreme to another with having and removing all the shims. Take one shim out and recheck it.

It shouldn't spin like a top when you spin and let it go.
 
You have probably ruined the bearings, you should have installed the spacer and shims torqued the nut to 240 ft lbs and check the preload with the inch pound torque wrench by rotating the pinion and looking for 20-30 inch pounds for new brg's or 0-15 for old bearings.

As far as preload for the carrier brg's go's loosen the right side adjuster till it has no tension on the carrier,turn the gear side adjuster in till there is no back lash, then turn the right side adjuster in till you get .006 - .008 back lash.

Of course you do know that you will also need to check your pinion depth, which requires a special tool.

Oh and and then you will have to run a gear pattern to make sure its all good to go.
 
crackedback said:
my 2 cents, you need to sneak up on the preload. Can't really go from one extreme to another with having and removing all the shims. Take one shim out and recheck it.
It shouldn't spin like a top when you spin and let it go.
Click to expand...

The instructions are telling me to start off with three shims and add or remove as needed. I started with three then two then one and even with one had a little wiggle room. When i take all shims out it seats. Should i file the solid spacer down a hair so I can use the shims?
 
Purple Haze said:
You have probably ruined the bearings, you should have installed the spacer and shims torqued the nut to 240 ft lbs and check the preload with the inch pound torque wrench by rotating the pinion and looking for 20-30 inch pounds for new brg's or 0-15 for old bearings.
As far as preload for the carrier brg's go's loosen the right side adjuster till it has no tension on the carrier,turn the gear side adjuster in till there is no back lash, then turn the right side adjuster in till you get .006 - .008 back lash.
Of course you do know that you will also need to check your pinion depth, which requires a special tool.
Oh and and then you will have to run a gear pattern to make sure its all good to go.
Click to expand...

What exactly did I do to ruin the bearings? Richmond gear is telling me to only torque it to 125 ft lbs. wouldn't 240 be a bit much?
 
The spec's I gave you are right from the FSM, as far as what you did wrong, if you preloaded the brg to much then you can't un do it.

You are probably OK since you did not get it to tight but the only real way to know is to check it with an inch pound torque wrench.

What did they say on how to check for pre load?

I will say that when it is set right it is tight, this is of course with new brgs.
 
Purple Haze said:
The spec's I gave you are right from the FSM, as far as what you did wrong, if you preloaded the brg to much then you can't un do it.

You are probably OK since you did not get it to tight but the only real way to know is to check it with an inch pound torque wrench.

What did they say on how to check for pre load?

I will say that when it is set right it is tight, this is of course with new brgs.
Click to expand...

They said to check preload the way you said. I guess I'll have to suck it up and get an in lb torque wrench.
 
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