Fj45 diff and gearbox (1 Viewer)

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Hey guys, I've got the 2f 4.2L motor, I'm looking at Changing my gearbox and doffs to a later model landcruiser just wanting to know if any will fit straight in, or keeping the 4 speed gearbox and changing the diff centres to a later model of they will fit.
If anyone knows of anything or can help me out that would be great

image.jpeg
 
diffs from 60 series, maybe 70 series also?, will drop right in, only issue would be the flange bolt patterns
 
I did 60 series diffs into my old 45 with the h42 4 speed box. Was a noticable improvement in cruising speed vs rpm.

Bolted straight in and I had the 60 series prop shaft so I used that and slid the 40 series uj shaft into the top so had no issues with flanges
 
I did 60 series diffs into my old 45 with the h42 4 speed box. Was a noticable improvement in cruising speed vs rpm.

Bolted straight in and I had the 60 series prop shaft so I used that and slid the 40 series uj shaft into the top so had no issues with flanges
Sweet as man thanks for that,that's what in trying to do get abit better cruising speed. that's a huge help cheers
 
Sweet as man thanks for that,that's what in trying to do get abit better cruising speed. that's a huge help cheers

no worries. glad i could help
 
G'day mothy, your truck would have 4.11 ratio diffs same as Australian market 60 and 75 series, changing to a 5speed will be the best way to gain better cruising speeds, this would be the most useful all round option in my opinion

Unless You wanted to keep the 4speed You would have too actually go earlier model Landcruiser, In this land downunder 3.7 diffs finished with the 3speed in 1972

Or if you're lucky enough to find an import 60 series as I've seen the odd one with 3.7 ratios
 
G'day mothy, your truck would have 4.11 ratio diffs same as Australian market 60 and 75 series, changing to a 5speed will be the best way to gain better cruising speeds, this would be the most useful all round option in my opinion

Unless You wanted to keep the 4speed You would have too actually go earlier model Landcruiser, In this land downunder 3.7 diffs finished with the 3speed in 1972

Or if you're lucky enough to find an import 60 series as I've seen the odd one with 3.7 ratios

Hey there catskinner,
Yeah I've got the 4:11 diff ratio, and that sounds pretty good,
What model would I grab the 5 speed out of or doesn't really matter because if have to be change the yokes anyway?
 
Hj75 or hj60~61, as long as it has 2h or 2f as they share the same input shaft, 1hz and 4 cylinder have a different input shaft and I don't know about 3f

The holes in transmission tunnel will need to altered as the gear stick position on 5speeds is further back, unless you can find a 40 series 5speed, pretty rare haha
 
Also the rear shaft will need to be shortened and front lengthened
Depending on your year model and where you get the 5 speed from the flanges may be the same
 
Hey mate, yeah as the cat said there's two options: 3.70 diffs centres or keep your current axles as they are and install a H55 five speed. But there's also a third option - 33" tyres. There's pros and cons for all.

3.70's.
Pros - no need to change gearbox, can do a full axle swap unless you currently run disc front.
Cons - low range no good when coupled with the 4 speed, lose a bit of torque down low, can be hard to find the centres.

5 speed.
Pros - future proof, popular, adds resale value
Cons - will require driveshaft length modification x 2, will require handbrake relocating to rear axle [will need a 60 series axle to rob parts from].

33's.
Pros - more lift, looks boss.
Cons - lose torque down low.
 
Hey mate, yeah as the cat said there's two options: 3.70 diffs centres or keep your current axles as they are and install a H55 five speed. But there's also a third option - 33" tyres. There's pros and cons for all.

3.70's.
Pros - no need to change gearbox, can do a full axle swap unless you currently run disc front.
Cons - low range no good when coupled with the 4 speed, lose a bit of torque down low, can be hard to find the centres.

5 speed.
Pros - future proof, popular, adds resale value
Cons - will require driveshaft length modification x 2, will require handbrake relocating to rear axle [will need a 60 series axle to rob parts from].

33's.
Pros - more lift, looks boss.
Cons - lose torque down low.

Is there any diffs that you could swap one with? Otherwise, what's the best place to get a centre from?
 

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