97 FZJ 80 Front and Rear Diffs Interchangeable? (1 Viewer)

Joined
Aug 8, 2020
Messages
56
Location
Michigan
Hello are the 97 FZJ 80 Front and Rear Diffs Interchangeable my front one blew and I figure if they are I will add an autolocker to the rear and call it a day.
 

Road Apple

SILVER Star
Joined
Nov 28, 2011
Messages
1,241
Location
Santa Cruz, CA
Unfortunately they aren’t. They are different in size and the way the gears are cut.
 
Joined
Aug 8, 2020
Messages
56
Location
Michigan
Unfortunately they aren’t. They are different in size and the way the gears are cut.
Damn, Well thank you. Do you think I would have better luck just going with an auto locker diff in the front? A used Diff on Ebay is over 1000$
 

cartercd

SILVER Star
Joined
Aug 31, 2004
Messages
684
Location
Chandler, AZ
Autolockers are not advised on the front diff of a full time 4WD truck. It would negatively impact your handling.
 
Joined
Aug 8, 2020
Messages
56
Location
Michigan
Autolockers are not advised on the front diff of a full time 4WD truck. It would negatively impact your handling.
I understand that risk, does the locker replace the inner diff should I go that route though or will I still need to find a front diff? I think I know the answer I just want to me 100% sure.
 
Joined
Aug 8, 2020
Messages
56
Location
Michigan
It would probably be a good idea to get ahold of the rig and figure out what you need before you start buying parts.
Well the diff is toast that I know, I am unsure about the ring and pinion. I would love to find a oem front diff whole set. I plan to autolock the rear I am just more so wanting to get it drivable. I don't want it sitting in the shop pissing off my mechanic because it needs parts.
 
Joined
Nov 9, 2012
Messages
13,240
Location
Olathe, KS, USA
Well the diff is toast that I know, I am unsure about the ring and pinion. I would love to find a oem front diff whole set. I plan to autolock the rear I am just more so wanting to get it drivable. I don't want it sitting in the shop pissing off my mechanic because it needs parts.
Try @arcteryx for a used one. Depending on location there may be other locals that have one. Look in classifieds above.
 
Joined
Jan 5, 2017
Messages
4,059
Location
Charlotte, NC & Alexandria, VA
It's hard to believe your differential failed catastrophically and your ring and pinion are fine. Those gears are too close together and bathed in the same oil, at the same time. Do you know what exactly is bad?

Also, what do you mean by housing? Are you referring to the carrier casting, or the differential case?
This is the carrier:
1664051121250.png


This is the differential case:
1664051162296.png


If you have a locker in your front differential, and that has failed, it does not mean the differential has failed.

If you do not have a locker in your front carrier, and one or more of the differential components have failed, or simply are worn, replacing them is much less expensive than you've quoted for used parts. This is all that comprises the differential:
1664051261144.png


Ignore the ring and pinion in the lower left corner (I didn't take the time to "professionally" crop this).

FWIW, I would not recommend installing used gears unless either you, or someone you know to be verifiably educated on the subject, has determined they are in like new condition. It's worse than installing used tires.
 
Last edited:
Joined
Aug 8, 2020
Messages
56
Location
Michigan
Thank you for your insight. The seller said the diff was trashed so he junked it and pulled out the axel arms so he could roll the truck out. I don't know what it looks side inside the housing so I am planning on replacing the entire diff with a used open diff I source here.
If I upgraded my ring and pinion to the 4:88 would I have to do the same to the rear? Would I have to do anything more than the ring and pinon for the regear?
If the front diff gears are the only thing that needs replacement, where would be the best place to get those parts?
 
Joined
Jan 31, 2005
Messages
4,079
Location
Denver CO
Classic Cruisers
Yota Jims
Car-part Search Results - https://www.car-part.com/cgi-bin/search.cgi
Oleg 10 Toyota LAND CRUISER 93-97, need work, Progects. PARTS. - auto... - https://denver.craigslist.org/pts/d/sedalia-10-toyota-land-cruiser-need/7528606980.html

You could probably get a front diff from any of them.

If you regear one diff, you need to do the other one too.

Probably best to talk to someone like east coast gear supply and see what it would take $$ wise. It’s not cheap to ship to them and have them do the work, but it’s also something most people don’t feel comfortable doing themselves. Making a mistake is very costly. If you are in there anyway you would also want to redo the bearings and seals. I had two diffs rebuilt by Zuk last year and it was like $800 apiece by the time shipping back and forth is taken into account. And that was bearings and seals only, the housings and gear sets were good.
 
Joined
Jan 5, 2017
Messages
4,059
Location
Charlotte, NC & Alexandria, VA
Thank you for your insight. The seller said the diff was trashed so he junked it and pulled out the axel arms so he could roll the truck out. I don't know what it looks side inside the housing so I am planning on replacing the entire diff with a used open diff I source here.
If I upgraded my ring and pinion to the 4:88 would I have to do the same to the rear? Would I have to do anything more than the ring and pinon for the regear?
If the front diff gears are the only thing that needs replacement, where would be the best place to get those parts?
OK, that makes more sense.

First, If you're going to buy a used, complete differential carrier assembly (that heavy thing between the propeller shaft and the axle housing that someone here is going to call a third member), you should be fine.

Just have someone check the seals, bearings and gear pattern BEFORE you install it. If you didn't, and it's bad, you'll wish you had. Even a used complete carrier assembly that needs gears, seals and bearings is worth having, it'll save you money in the long run. What you don't want is someone to sell you a purportedly good assembly, that you then have to repair, on your dime.

If you don't know how to assess one, either find someone who is highly reputable to buy from, or take someone that knows (is verifiably educated, I mean) what to look for with you.

Second, yes, the front and rear gear ratios have to match. Toyota put high gear ratios in the 80s so they didn't whine on the highway. The older FJ40s had 4.11s in them; Toyota replaced them with 3.78s to quiet them down. Big mistake, IMPO.

Toyota parts are always best. Several stateside dealers, like McGeorge in Richmond, VA, sell OEM online at discounted prices. Overseas dealers, like PartSouq and Amayama, sell OEM parts even cheaper, but heavy ones, like gears, cost you dearly to ship. Aftermarket dealers abound here, I haven't bought from any, so you'll have to ask around for opinions. A word of advice, that you didn't ask for: you can pay $10 for a gear that looks just like an $80 gear. Unless you work for a gear manufacturer, or a very well equipped shop, you won't know the difference until it fails...80 miles from nowhere.
 
Last edited:
Joined
Jan 5, 2017
Messages
4,059
Location
Charlotte, NC & Alexandria, VA
OK, one last thought for you: repairing a differential carrier assembly isn't hard, or require tools you won't likely have, unless you want to use a dial indicator. There is a way around that-I used to manage an automotive assembly line that built heavy duty off-highway drive-steer axles. We didn't use a dial indicator. Get a copy of the FSM and read up on the job. If you decide you want to do it, and save yourself several hundred dollars, and need a hand, give me a shout.
 
Joined
Aug 8, 2020
Messages
56
Location
Michigan
Yall are the best. I will confirm with the seller as to what exactly in the diff he junked. from the photos the driveshaft is attached to the third member and axle still there.
I am expecting its empty in the housing.
 

Users who are viewing this thread

Top Bottom