Did the fj40s get the split transfer case in 1980 at 2.28?
Ring and Pinion strength 3.83 vs 4.11
- Thread starter deneric
- Start date
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Axle spline-wise, yes, but he is talking pinion splines.
Ed
Ed
rsbcruiser
SILVER Star
Just do it
There are several drive line shops right here in town, me I'd do it myself. Loads of fun and beyond cool to do. You will need a magnetic base and a 0.001" indicater, shockingly cheap but junk at HF. A big bench vice and a big breaker bar, and a big hammer (the fun part). Instructions come with the rebuild kits. I went the shim and not the crush sleeve route, use the special sauce to check your gear pattern. Real straight forward and after you are done, job satisfation level is high. Oh and loctite red and punch set that pinion nut real good. Or that nut will come loose. Not that that happened to me, oh no never.
There are several drive line shops right here in town, me I'd do it myself. Loads of fun and beyond cool to do. You will need a magnetic base and a 0.001" indicater, shockingly cheap but junk at HF. A big bench vice and a big breaker bar, and a big hammer (the fun part). Instructions come with the rebuild kits. I went the shim and not the crush sleeve route, use the special sauce to check your gear pattern. Real straight forward and after you are done, job satisfation level is high. Oh and loctite red and punch set that pinion nut real good. Or that nut will come loose. Not that that happened to me, oh no never.
I have 75 with 3.70 stock and H41 box
From the plates:
Model FJ45RP-KW
Frame/Vin FJ45/095789
Trim 653 LC11
Trans/Axle H41 K052
Engine 2F0016607
Since we're on the subject . . .
I blew up the rear end in my '78 FJ40 and replaced the pumpkin with one from a '76. Both diffs (currently out of the vehicle) are 4.11 but one is fine spline and one is coarse spline.
I'll be running a 383 Stroker, 700R4 and Orion 4:1 with ARB's at both ends.
Do I need to be concerned about the coarse spline pinion? And am I better off with it in the front or rear?
I blew up the rear end in my '78 FJ40 and replaced the pumpkin with one from a '76. Both diffs (currently out of the vehicle) are 4.11 but one is fine spline and one is coarse spline.
I'll be running a 383 Stroker, 700R4 and Orion 4:1 with ARB's at both ends.
Do I need to be concerned about the coarse spline pinion? And am I better off with it in the front or rear?
Generally speaking, a fine spline pinion is stronger than a coarse spline pinion, and I would install the fine spline pinion in the rear. However, if your last ring and pinion failed because of a drive shaft binding, a fine spline pinion will fail the same as a coarse spline unit in this application, every time.
With that said I have some better questions for you:
Why did your last differential fail?
What were you doing when it let go?
What engine/trans combo was in your truck at the time?
What is your suspension configuration?
What is your intended use for this vehicle?
Dang Poser, I was trying to get out of this without telling a huge embarrassing story.
Here goes . . . I was in the process of installing a 4" HFS lift. Once I got the springs installed I decided to take it for a drive around the block. For some reason (i'd like to think it was a good one but I don't remember) I hadn't installed the shocks. I knew the driveline was a bit short but what could happen going around the block?
Well, two dips in the road fairly close to each other is what happened. As I went over the second hump the driveline separated, came around and smacked the frame (you might call this driveshaft binding) then sheared the pinion completely off at the flange. The pinion went into the diff and tore it up. As if that wasn't bad enough, I had recently installed an ARB (had less than 1,000 miles on it) that had to be mostly rebuilt.
Add in the tow from a roll-back wrecker for the 1/2 mile back to the shop and you have one really expensive trip around the block.
To answer your questions:
Why did your last differential fail? operator error
What were you doing when it let go? test drive
What engine/trans combo was in your truck at the time? 2F/4sp
What is your suspension configuration? new lift springs and no shocks. It will have springs up front and a 4-link with 1/4 elip. in the rear.
What is your intended use for this vehicle? 50% show - 50% go. It will be well built to handle serious off-roading yet look good while cruising around town. It won't be a DD by any means and I intend to trailer it to trailheads.
Ouch! Hopefully your story will keep someone else from doing the same.
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