Gears and shims

[Repostyle]

So, I've got a spare rear end that I'm putting a motive bearing kit in with FRPP 3:73's and 28 spline 5 lug ranger axles. I'm also putting on SN95 gt disk brakes but that doesn't matter for this question.

My question:

I've found some info on the pinion gear depth settings, but I can't find anything to get me close on my first fitting of the rear diff. backlash. Has anyone ever installed gears themselfs and could maybe give me the right and left shim thickness you used for your 373's? And did you use the old bearings and shims or new ones?

 

[superhuaman]

start with the old ones...sometimes they wont fit, so you have to use skinnier ones to just slip-fit. then torque the bearing caps to 80 ft-lbs, and if your backlash is within range (.008" to .015", .011-.015 preferred) then add i believe .010" to each side and youre done

 

[Repostyle]

If it is in range with the old ones, why would I add .010" to each side?

 

[red95gtconvert]

When I installed my 3.73 gears last weekend I just reused the .030" shim that was on the old 2.73 pinion gear from the factory and it worked perfectly. I ended up with .010" backlash and have no whining or funny noises. Make sure you use red loctite on the pinion nut to prevent it from backing off on you. If this is your first gear intsall I wound set aside a couple days to do it and work slowly.

 

[superhuaman]

If it is in range with the old ones, why would I add .010" to each side?

If the old ones work, you just use them...
But if they're too big, you have to start with smaller ones to get the backlash right.
When you add .010" per side after backlash is set, that sets proper carrier bearing preload.

 

[red95gtconvert]

Just remember that when you shim the carrier to move the ring gear over you add a shim to one side and take way that size shim from the other side. If you are using Ford racing gears it's really not that hard to install the gears, it's just time consuming.

 

[Repostyle]

If you are using Ford racing gears it's really not that hard to install the gears, it's just time consuming.

That's why I got the spare rear end, that way I can rebuild and upgrade it on the bench and still drive my car till it's done then just do the swap.

Thanks for the help guys.

 

[superhuaman]

That's why I got the spare rear end, that way I can rebuild and upgrade it on the bench and still drive my car till it's done then just do the swap.

hey thats what i did, it worked great...
of course, i upgraded my 7.5 to an 8.8, so i kind of had to do it that way lol.