1972 fJ40 conversions (1 Viewer)

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I have a 72 FJ40 that I am attempting to rebuild. It has a 1986 Chevy 350 that runs pretty well and the original 3 speed stick transmission and T case. I really need a 5 speed and have been reading about the various transmissions (NV4500, H55f and R151f) that can be used. I am leaning toward the NV4500 because Advanced Adapter has a conversion kit where I can use the original T case. Does anyone have an opinion on which way to go?
 
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Hi LilJohn, The intended use is a little country cruising and town driving. I will be towing behind my motorhome. Once upon a time a rock crawled all around the Rockies in my 69 FJ40 and my 81 FJ40. Just getting too old to bang myself up too much. Still love the FJ40s and want one I can drive daily and then pass on to my grandson. Will be upgrading tires and wheels, have not decided what yet. Gearing I think is 4:11 stock.
 
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Brian stole my thunder. ;) It sounds like you might be better served by just getting an LC four speed. At no point do you mention "lots of highway miles" ;)
True, but there will be some. Don't want to get run over by the traffic.
 
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With a V8, you will have no issue getting run over. I can easily hit speed limit without OD in my FJ55:
View attachment 2513743
That is me in the 55 in the fast lane playing "chase" with another mud member running my V8 without touching OD. It took traffic for him to "catch up" ;)
Then maybe I should consider a 4 speed and split tcase. what combination would be the easiest to put together?
 

brian

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Then maybe I should consider a 4 speed and split tcase. what combination would be the easiest to put together?

fyi, the 4spd doesnt offer any more rpm reduction than the 3spd....both are 1:1 in top gear.
swapping the rears to the later 3:73-1 gear ratio and adding 33" tires will do far more than swapping to a 4spd with what you have now.

my 2F with a 4spd, 33's and 373 rears does 70-75 effortlessly on the open road with rpms well in check.
 

DangerNoodle

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Depending on where you are, I have both an h42, a single piece case, or a split case I can let go.
 

DangerNoodle

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The front axle will be about 3" wider than the stock 40 axle, but the rest should go in. You may need a different bell housing, and I believe you will lose your parking brake with the 60 split case.
 

DangerNoodle

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I am in Loveland CO. What would you want for the H42 and split case?

Nice! I'm a little above Colorado Springs. I'm not sure you would want the split case as the spline count is different than the H42, and I already have someone in line for it, but I do have a rebuilt single-piece case that would mate to the H42. It's a pretty rare case, as it is a 34MM idler with helically cut gears. It is a lot stronger than the original cases that came in the 40s and a bit quieter. I'll send you a PM and we can talk about prices. I'm sure @orangefj45 can explain that case better.
 
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Will the front axle, 4 speed trans and t case out of a 81 FJ60 bolt up to my 72 FJ40?

Not really.

front axle housing the spring perch width is different, so not bolt on. the knuckles could be used for disk brakes, but you then need to do something with the steering arms/linkage.

Any of the 4 speeds will take a bit of messing around. You will need to get a bell housing that adapts to the V8 and (maybe) lose the rear mounts, depending if your V8 was installed with the common used propeller style rear trans mount or stock. Using a split case version like the 60 had gives you a stronger/quieter transfer case, but then you need to figure out parking brake with either newer rear axle or less common non-US market conversion parts for t case. If your V8 is moved forward the 60 version places the shifter further back which will help. Then you still have to sort out shifters/tranny hump/body interference, maybe some clutch setup changes given different bell housing and different splined input shaft, source driveshafts, set up mounts, skid plate, etc. as you would need to for any trans swap.

The stock h42 4 speeds are smooth shifting, give a bit better first gear than 3 spd and closer gear splits. For the mostly road use you mentioned it would be a good choice. The h42 itself can be found fairly cheap but there is still a bunch of stuff needed to make it work in your application that is also needed for any tranny you choose to swap over. An nv4500 is a good choice especially if you want a wider gear spacing, decent shifting, a much lower first and overdrive. otherwise the 2nd to 4th would be close to same gearing as you get from you current 3 spd.
 

DangerNoodle

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Funny enough, I have a SBC to H42 bellhousing as well. I can basically supply you with an entire drivetrain that will mate if you want. The NV4500 is what I run in all my rigs. Its a great transmission, but it will get expensive to put in. You will need find a cheap core to rebuild, then get the nearly $700 adapter to adapt the NV to Toyota t-case. It adds up quickly. Your driveline will also get shortened. A lot. The NV with adapter is right around 18" long, then add the t-case on. Just some food for thought.
 

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