Advice wanted - Time to rebuild the rear diff

[RhinoRig]

Hey all. The rear diff on the 1985 HJ75 at least needs new bearings, so I was thinking about throwing in a new gear set and lockers. How do you tell the existing gear ratio? Any advice on US market gear sets and lockers? Are the guts the same as on 60s and other models in 1985? It seems like that was a year of change over, so how do I know I'm getting the right bits? Thanks

 

[wardharris]

Hey all. The rear diff on the 1985 HJ75 at least needs new bearings, so I was thinking about throwing in a new gear set and lockers. How do you tell the existing gear ratio? Any advice on US market gear sets and lockers? Are the guts the same as on 60s and other models in 1985? It seems like that was a year of change over, so how do I know I'm getting the right bits? Thanks

The truth is out there.....
See here for secret password Gearratiosanddiffs on your gear ratio - probably 4.11
You have a 9.5" diff. If you do not have locker levers on the dash, it is not a manually actuated cable locker.
Same unit in 40 Series through 80 Series - nice 'n beefy.
I don't sell gears, but our installer friends like Nitro brand. Koyo bearings are well regarded.
I do sell manually actuated electric locker (Harrop Eaton ELockerTM) video here.
Guess the questions are: what do you want to do with the truck, do you want to re-gear, do you need locker (auto or manual) and what is your budget?
Another question - who does your work, who do you trust, are you up for a DIY project?
Ken Francisco at Gear Installs @gearinstalls.com is a good guy and gives good advice - he doesnt sell lockers, gears, etc. just does third-party differential set-up for owners and shops that wish to outsource the installation of gears, bearings, locker, etc. in the differential carrier.

Good luck

 

[gearinstalls.com]

Hey all. The rear diff on the 1985 HJ75 at least needs new bearings, so I was thinking about throwing in a new gear set and lockers. How do you tell the existing gear ratio? Any advice on US market gear sets and lockers? Are the guts the same as on 60s and other models in 1985? It seems like that was a year of change over, so how do I know I'm getting the right bits? Thanks

Hi RR-
Another way is to count the driveshaft turns.....jack 1 rear wheel off the ground....with tranny in N turn the wheel exactly 2 full turn while counting the ds turns......if it turns 3.7 times then that's what you have....if 4.10 then there you go. The guts are the same with the 60's....I have a 1985 FJ60 front end that I transplanted under the front of my 01 Tacoma recently and am so happy with it. Mine came with 370 gears, by the way.

The $60 question is do you have a full floater rear? If your rear diff cover is removable then it's a semi floater....if it's welded on it's a full-floater. I hear if you have disc brakes in the rear then it's a full floater, too.
edit----I have the matching 1985 FJ60 rear that I decided not to put in my Taco.....it has big massive drum brakes....and the removable cover so mine is a semi-floater and, as a result, also takes the c clips.

Thanks for the plug Ward

Ken

 

[wardharris]

I am pretty sure the 75s are all FF but good to check.