pinion seal

Joined
Aug 2, 2002
Messages
5
I may be just an idiot, but here goes...Have a '74 fj 40. 350, nv4500, 3 sp t-case, SO, lockers, PS, 8274, etc. (me braggin') and its puking oil out what iIbelieve is the rear pinion seal (not braggin'). Needless to say it's a mess. The rig is kept at our other place so next time I was there I was going to replace it. I have limited tools there so i was wondering if any one knew off hand which specific size wrench/sockets i need to remove the pinion nut? also any part numbers of maybe an aftermarket seal? they are usually cheaper than factory stuff. Any problems with messing up bearing preload if i just take it off and put in a new one? do i need a new nut? thanks in advance.
Mark
 

PabloCruise

 
 
Joined
Jun 3, 2004
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Mark,

Welcome to MUD! Sounds like a nice 40 you have there! Do you have any vibrations at speed?

You may not like this, but if the seal is leaking, you may have spun a shim, in which case your pre-load is messed up now - causing seal to leak.

Other factors that may be in play: clogged breather (easy to fix - don't forget to check) and a groove in your flange surface (requires new companion flange or a speedi-sleeve)

I have learned these things the hard way - believe me. I would use the factory seal. Maybe order up a few shims from the dealer as well. Bring some sand paper and an inch-lb torque wrench OR fish scale and ruler, and be prepared to replace the shim and sand your washer to set the preload.

Read about my trials and tribulations here: https://forum.ih8mud.com/showthread.php?t=49036

A handy trick to avoid ruining your new seal (yep, I have done that too!) is to use the flange as a driver. So place flange on pinion backwards, hold a piece of scrap wood on end of flange and hammer down.

A seal puller would be another handy thing to bring to the party.

Good Luck!
 

Pin_Head

 
 
 
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Feb 6, 2002
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Measure the preload on the pinion before you disassemble it, so you have areference for what the preload is. You can use a fish scale on the flange holes if you don't have and inch pound torque wrench as this will get you in the ballpark. If the pinion nut is still tight, then just replacing the seal may be easy. You will know because when you torque the flange back on, the preload will be the same as before you disassembled it.

If the nut is loose, the shims may be bad and you will know after you torque the flange back on because the prelaod will be way too tight. If the preload is bad, I would just get another good 3rd member (if you have a "lunchbox" locker in there). If you have and ARB or Detroit, you will need to reset the pinion preload.
 

PabloCruise

 
 
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Just make sure you dig in there and verify your shim(s) are intact.

You'll have to fish out the forward bearing...

Amen to the breaker bar - have someone who can stand on the brakes?
 

cruiser_guy

 
 
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Jan 20, 2003
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Wherever the truck stops!!
Well if you tighten it down and are able to turn the pinion by hand then the bearing preload and shims are OK. The third member in the FJ45LV was loose because the idiots left the nut loose like a typical Central American mechanic rather than use the correct shims and doing it right!! I ended up needing about 1mm worth of shims to get it right.
 

PabloCruise

 
 
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Yes, but if he tightens it down and the shims were not o-k, then he has wasted a new pinion seal - he will need to tear it out to get to the shims...

I would rather spend a few extra minutes to avoid wasting a $15 seal...

I say this because I have trashed about three of them by not knowing what I was doing.
 
Joined
Dec 18, 2004
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PabloCruise said:
Amen to the breaker bar - have someone who can stand on the brakes?
Breaker bar? How bout an impact gun! If you don't have one, sounds like a good excuse to buy one..... If you don't have an impact and the nut is being a bastard, take a grinder to the areas of the nut that are "staked", taking care not to hit the threads. If you grind it down a little it will be way easier to take off with just a breaker bar. Don't forget to re-stake a new nut (buy one at the dealer when you buy the seal) with a hammer and punch (2 places) or you will go through all of it again (or worse) very shortly.

Another tip is if the pinion drops a little into the third just push the cruiser backwards a little and it'll push right out.
 

cruiser_guy

 
 
Joined
Jan 20, 2003
Messages
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Wherever the truck stops!!
PabloCruise said:
Yes, but if he tightens it down and the shims were not o-k, then he has wasted a new pinion seal - he will need to tear it out to get to the shims...

I would rather spend a few extra minutes to avoid wasting a $15 seal...

I say this because I have trashed about three of them by not knowing what I was doing.
Yep, proper proceedure is to set up the shims first by trial and error and when the shims are good then pop in the seal.
 
Joined
Aug 2, 2002
Messages
5
Thanks so much for the info. Nobody mentioned adult beverages... after a job like this is beer the required celebratory drink or will jack and coke be O.K.? Maybe both? Thanks again!!!
 
Joined
Dec 18, 2004
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lambonius said:
Thanks so much for the info. Nobody mentioned adult beverages... after a job like this is beer the required celebratory drink or will jack and coke be O.K.? Maybe both? Thanks again!!!
How bout combining the 2 and have a boiler maker...... a shot of JD in a beer? :beer: :beer:
 
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