Rear axle pinion nut (1 Viewer)

[emac]

I had my driveshaft off to remove the tranny on my 88 FJ62 and noticed the pinion nut was loose (partially staked) and there was a lot of play. I tightened it up but it seems like (according to FSM) that I have too much tension and need to replace the crush spacer. Part 41231 in picture.

My plan is to get a new spacer, nut and oil seal. Install it and tighten to spec. Does this sound reasonable or am I missing something? Thanks.

 

[Randy88FJ62]

Depending on your budget it may be a good time to replace the pinion bearing, especially since the nut was loose. Also, if you are doing the diff setup yourself as it seems you are then maybe consider a sold spacer with shims. Superior to the crush washer.

Be gentle with the dust seal when you re-install it as it will make noise if bent and rubbing.

 

[emac]

Thanks Randy, I got home tonight and took it apart. The crush sleeve cant be removed without removing the bearing race. I am in debate how deep I want to go. I will have to replace the bearing and the race. I wasnt having any issues, so I am thinking about putting it back together as close to spec as I can with a new seal.

 

[Randy88FJ62]

Do it right or do it twice. Ask me how I know

 

[emac]

I know. I am just trying to figure out a way to get the race out. I cant find a puller that looks like the SST in the FSM. I dont want to cut it. Thinking of using the old weld a bead trick.

 

[Randy88FJ62]

I thought the race could be easily pounded out from the other side. I have a spare diff at home. I'll have to take a look. hmm.

 

[emac]

I was going to try and avoid going into the back of the diff. FSM shows replacing from driveshaft side.

 

[Randy88FJ62]

The pinion oil seal requires pulling the diff apart. If you don't care about replacing the seal then you can just tighten the pinion nut at hope for the best.

 

[emac]

The seal is just behind the dust cover (41201C in diagram). I have it out.

 

[Willard]

Even so with the crush spacer you still need to set the preload I believe. So if you are at that point, might as well just get a kit and go through the whole thing as you need to basically tear it apart to do it right.

 

[emac]

Perhaps, but I am just going by the FSM. It says if the preload isnt right after tightening the nut, then you need to replace the crush sleeve. The inner bearing has a shim to set the gears (41201D). I am not convinced I did a good job measuring the preload. I hacked together my in/pd torque wrench to the 1/2 socket. I have ordered some adapters to go from 1/4 in drive to 1/2 socket. Then I can really see where I am. I am not in a hurry, so I will continue to read.

 

[RustyNailJustin]

How are you reading preload? Take into account drag from preloaded carrier bearings assuming you still have the carrier in there.

 

[emac]

I am putting the torque wrench on the nut and turning it just trying to measure the slack between gears. Not turning the wheels.

 

[RustyNailJustin]

No, slack between

I am putting the torque wrench on the nut and turning it just trying to measure the slack between gears. Not turning the wheels.

"Slack between the gears" is backlash. Unless you removed the carrier you have not messed with backlash. Unless you know the carrier bearing preload you are going to have a hard time knowing what exactly your pinion bearing preload is.
Its best to set pinion bearing preload with no carrier in place. But is can be done if you assume the carrier bearing are with in range of spec then subtract that number from your pinion bearing reading. Once you have done it a few times you get a pretty good feel for it, you know when you are close and adjust from there.

 

[emac]

That makes sense. Thank you. As others have said it may be best to go through the whole thing.

 

[Prairie Swamp]

"Slack between the gears" is backlash. Unless you removed the carrier you have not messed with backlash. Unless you know the carrier bearing preload you are going to have a hard time knowing what exactly your pinion bearing preload is.
Its best to set pinion bearing preload with no carrier in place. But is can be done if you assume the carrier bearing are with in range of spec then subtract that number from your pinion bearing reading. Once you have done it a few times you get a pretty good feel for it, you know when you are close and adjust from there.

Not to get too technical as it's all a guess if you're not tearing it all apart - but remember that the ring and pinion gears are a torque multiplier. So if your carrier bearing pre-load is 20 in-lb it would only read 5 in-lb (assuming 4.11 gears) at the pinion.

If you're not tearing it apart replace the crush sleeve and seal if you can and torque to factory spec which might be up to 200 ft-lb I think. At high miles it's possible your carrier bearing pre-load is low but that doesn't mean your going to have a problem especially at 3FE power levels.

 

[Willard]

Pulled this from the Heavy Duty manual 1984-1990.

This is after you put in the crush spacer

 

[emac]

Yep, that is what I was going by. Thanks

 

[Willard]

Yep, that is what I was going by. Thanks

I did the one in my Bronco. I can tell you that crushing down the spacer and getting the preload right is not as hard as it sounds.
The key is to tighten, measure, tighten, measure. Keep doing that in smaller increments until you have it right.

 

[emac]

My plan is to replace the crush sleeve, put in a new race/bearing and oil seal. Tighten to spec and see where it goes. My only issue is getting the race out. I bought tool online that looks similar to the sst that I think I can make work. from the way I read the FSM you are measuring the friction to turn during the backlash. No matter what I do, it will be better than before and it wasnt giving any problems.