axle options

[jrcrawly]

I am rebuilding a '73 40. I have a '71 and an '81 for parts. Should I use both axles from the '81 or stick with the old-sytle brakes? Also, will the 4.10 gears from the 73 fit in the 81 axles?

 

[Josie'sLandCruiser]

Hi All:

Use the '81 disc brake frontend, but with the third member from the '73 rearend.
Use the '81 rearend with the third member from the '73 frontend. You will need to do some mixing n' matching of drive shafts to get the '73 pinion yokes to work.

Do you have the four speed transmission and t-case from the '81? That is what I'd use.

Good luck with the project!

Alan

 

[jrcrawly]

sounds like good advice, but why the put the 73 rear third member in the front of the 81 and the 73 front in the 81 rear? The 4-speed and split tranny are being saved for a future project. The 73 is getting a 350TBI and 700r4.

 

[zuluzeugma]

IIRC 81' gears are 3.73:1

 

[cruiserbrett]

on the third member front to back swap, they are identical front to back with the exception of the block and c-clips(you can swap them no problem) so you end up with the low milage front 73 4.11 diff in the rear 81 axle. After all, how much time was spent in 4wd in the '73?

 

[FJ40Jim]

79-later FJ40 gears are 3.70 (37/10)
78-earlier are 4.11 (37/9)

Be aware that using the 81 rear housing will require the 81-later drum brakes that are self-adjusting by use of the parking brake. You'll need to fab a brake cable or figure a way to swap in the floor mounted brake handle and use a stock 81-later cable.

I would suggest using the 71 housing w/ the common RDB conversion and keep the 73 transfer mounted P-brake.

 

[jrcrawly]

I have the full '81 donor truck so I could pull the entire ebrake assembly. Is the option of using the '81 axles prefered over the transfer case mounted ebrake on the older axles? I also mentioned the truck is getting a 700r4, any ideas on a good torque converter?

 

[Josie'sLandCruiser]

Hi All:

I'd suggest using the the '81 rearend with p-brake, and also using a Land Cruiser "split" t-case from a FJ60 (its like the '81 FJ40 t-case) instead of the one-piece '73 t-case. The "split" t-case is much stronger and quieter than the older style (a good match with the SBC & auto trans) but does not use the t-case mounted p-brake.

Regards,

Alan

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I have the full '81 donor truck so I could pull the entire ebrake assembly. Is the option of using the '81 axles prefered over the transfer case mounted ebrake on the older axles? I also mentioned the truck is getting a 700r4, any ideas on a good torque converter?

 

[jrcrawly]

Using the split t-case sounds like the way to go, however, I already bought all the converters for the three speed t-case and I have a spare for parts.

 

[fyresq]

Although you do get lower gearing by using the earlier thirds, you also get coarse spline pinions which are notoriously weak. I would stick with the 81 (fine spline pinion) axle and regear if you want to be lower. You may even want to keep the 3.73 for mileage with gas prices these days.

 

[FJ40Jim]

Although you do get lower gearing by using the earlier thirds, you also get coarse spline pinions which are notoriously weak.

That's true. The 350TBI plus 700R4 will make some pinion crunching torque.

 

[jrcrawly]

Sinice I already invested the $ in the three-speed transfer, the advice to use the split transfer comes too late. This will be my wife's truck, if she pukes the three-speed transfer, I guess I'll rebuild. Consdiering the use will me more around town, long trips to off road areas and not very extreme wheeling, should I go with the 3.73 or 4.11 gears. I am thinking about a 2" lift with tires no bigger than 33"?

 

[Mace]

3.70's will be perfect for 33's.

 

[Josie'sLandCruiser]

Hi All:

"Notoriously weak" coarse-spline pinions, huh? Whatever . . . . I know several V-8 powered rigs still running coarse-spline 4.11 thirds without breakage (knock on wood! )

Ah, if you "regear" from 3.73 you would loose the fine-spline pinion; except that all ratio aftermarket R&P sets are fine spline!

"Jrcrawly," I didn't realize that you were running a 350 SBC with 33s - 3.73s would probably be a good choice for a highway runner and mild 'wheeler.

Regards,

Alan


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Although you do get lower gearing by using the earlier thirds, you also get coarse spline pinions which are notoriously weak. I would stick with the 81 (fine spline pinion) axle and regear if you want to be lower. You may even want to keep the 3.73 for mileage with gas prices these days.

 

[fyresq]

"Notoriously weak" coarse-spline pinions, huh? Whatever . . . . I know several V-8 powered rigs still running coarse-spline 4.11 thirds without breakage (knock on wood! )

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Ok.....let me rephrase that. They would be a weak link in your offroad rig. I've seen guys run 39's with a dana 30 front too, but it doesn't make it ok. Also regearing does give you fine spline if you buy new, but what about disk brakes?......I still say go 81's. Or better yet....use the thirds and discs setup from the 81 and swap into 71 so you don't have to mess with the e-brake since you are already using the 3 speed case with e-brake. I hope I don't offend (Josie)you when I call the coarse spline birf's weak too?

 

[Fast Eddy]

I didn't realize that you were running a 350 SBC with 33s - 3.73s would probably be a good choice for a highway runner and mild 'wheeler.

x2 Great combo for the .