3rd Member Swap: Pinion Preload Problems (1 Viewer)

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Swapping FJ60 3rds into my '40. Both 3rds appear to be in good condition, but pinion preload on the rear 3rd (which I will install in my front axle), was WAY high--hard to turn by hand. I had to back the lock nut off about 1/4-1/2 turn to get the preload right. If I torque the nut down to spec, the preload is so high I can't turn it without serious effort.

What's going on?

BTW: I'm reading the Toyota 1980 Chassis FSM for the FJ40--but preload is set the same for the FJ60 3rds isn't it?
 
preload is in inch pounds. it should be less than 20in lbs. something like 9-16 inch lbs

YES, sorry. It looks like I'm going to have to go deeper and see what's going on.

Edit:

It should have crush sleeve in it unless someone previously installed a spacer.

A quick search indicates that they were solid sleeves until around 1984.
 
what did you change. if it was properly set up it should retain preload if its torqued to the same value it had before. In my experience even with shims the preload will change slightly while torquing the pinion nut.

I didn't change anything. The preload was (WAY) high when I bought it. I came here to address the issue before I installed it.

Perhaps it has been damaged, and I'm not seeing it, or perhaps the PO took it apart and lost a shim or two. I just need to address the issue and get my truck back on the road.

Thanks for the quick replies. :cheers:
 
As far as i know the 3.70s in the FJ60s never came with the shimmed pinions. If it has a non crush sleeve pinion it is likely a 4.10 not a 3.70
 
...
Perhaps it has been damaged, and I'm not seeing it, or perhaps the PO took it apart and lost a shim or two. ...

Have seen them crack/spit shims. If everything else looks good, properly shim it and run it. Especially on the front, they don't see a lot of high speed operation, so :meh:.
 
Have seen them crack/spit shims. If everything else looks good, properly shim it and run it. Especially on the front, they don't see a lot of high speed operation, so :meh:.

Thank you Tools R Us and roma042987!

OK, Wow, now I have another hurdle to clear. The bolt pattern on the pinion flange doesn't match my '77 driveshaft. Looks like I can just rotate it 45 degrees and drill to match [what could possibly go wrong with that?!! :doh:] is that what most people do?

Please advise. :)
 
... The bolt pattern on the pinion flange doesn't match my '77 driveshaft. Looks like I can just rotate it 45 degrees and drill to match [what could possibly go wrong with that?!! :doh:] is that what most people do?

Please advise. :)

That works and is commonly done.
 
Now, I will need to add shims to decrease preload?

You need a thicker preload "washer". This is the thick shim you will find. You can have 0 to 3 thin shims (.010 thick) which accommodate the different pinion depth shims and there are 25 different size preload washers to select from to get the proper pinion preload. Since you may have problems finding the washer set, you can also add another thin shim and then carefully sand the washer down to get the proper preload. .0005 inch thickness change corresponds to about 2-4 inch pounds of preload, so check often once you get some preload.
 
Thank you gentlemen! :cheers:

I just used a driveshaft yoke flange as a guide and drilled the pinion flange out on the drill press. Worked well and that saved me time and money.

I cracked into the 4.11 3rd I removed from the rear of my DD to look for shims. The Pinion nut was not punched, it was torqued on to about 15 ft. lbs., and the oil slinger was in backwards! (I'm beginning to wonder how forgiving these tolerances might be as this work was done by the PO and I've been driving it this way for years.)

The other spacer washer was the same exact thickness but I really lucked out--one more shim and the preload was perfect! I just got the backlash and overall preload right. New pinion seal and in it goes. [HOPEFULLY]
 

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