Tercel interchangable parts

[sunray]

Wow, lots of feedback!

So just on the note of the diff sizes, the third members can have different numbers of bolts irregardless of the diff used inside. There are two types of s code diff. One has 2 pinions (real crap) and one has 4 pinions (not so crap). By pinions I mean the pinions that hold the spider gears. They still use two side gears inside the case but spread the load among 4 spiders on the 4 pinion diff. If some alltracs have a 6.7" diff then that is pretty cool its just the last one I had up in the air did not.

The diff size is measured on the crowngear flange. Its the inside diameter of the crowngear.

The design of all of the diffs (s, t, etc) are a copy of the ford 9" so the basic design is very good. The trouble is size. The s code hates being beaten and really hates anyting above 100hp. Thats why I hate them. The T diff handles things well up to 200hp and has a HUGE aftermarket support thanks to the drifting community. They even have some lsds with 16 clutches!

The 7.5" diff can handle stuff up to around 500hp pretty well, obviously way outside of tercal range, lol!

Why do I dislike discs in the rear of a 4x4? Simple, I fix cars for a living. They started introducing rear discs on trucks as a selling point for soccer mom's who don't offroad. They perform very well on the street compared to drums but on the rear of a truck they DO get very clogged with muck and the linings and rotor faces suffer brutally as a result. Ask some of the ford owners of things like f150s and escapes how often they have had to replace rear rotors.....at $180 or more each. The drums are win for the rear because they keep crap out by design. The linings last a long time and the parking brake portion works way better. Those ae86 (gts) rear discs have a cammed piston which drives very little force against the pads. Most guys with rear disc are forced to use a hydraulics ebrake. Basically, don't believe the hype.

[ARCHINSTL]

The design of all of the diffs (s, t, etc) are a copy of the ford 9" so the basic design is very good. The trouble is size. The s code hates being beaten and really hates anyting above 100hp. Thats why I hate them.

So - what you are saying is - they are very good for what they were intended? Therefore the problem is...?

Now, I haven't "offroaded" since driving a green thing over 40 years ago, but - don't "real" Jeeps, et al, come with discs on the rear? Didn't the engineers listen to offroaders?
Tom M.

[Petros]

Sunray,

According to the link the diff code is on the data plate under the hood or on the door post, but i can find no such code in either place on my '84 Tercel4wd. If the code is correct I should have the S304 or S302 (two or four pinion spider gears), but I can not find either anywhere. Is there another place to look?

I took a look at the all-trac diff, and the third member is definitely different from the Tercel (larger), but if what you say is correct it could still have the S type diff. I am going to check the data plate on my other '86 tercel and the all-trac and see what it says. The input flange on the all-trac has a slightly larger bolt pattern from the Tercel as well, so there would have to be a custom driveshaft made for it to fit.

Is it possible to make the T type diff fit into the Tercel rear axle housing? Or would that require too much machining. So the best we can hope for in the S type diff is to find the 4 spider diff, and there are no LSD available for it? It there anyway to know what cars the S type 4 spider diff came in from Toyota?

If we want the T diff with LSD one would have to swap out the whole rear axle from a RWD corolla GTS (hard to find). There was a thread about the rear suspension on this list, and I had measured and inspected the IRS rear end from an '85 Celica GTS, it appeared it could be made to fit under the Tercel, do you know anything about this whole rear end set up? It had the diff mounted on the sub frame, as a separate unit. It seems there should be a wide range of ring and pinion gear sets available and an LSD too, for the GTS diff.

[sunray]

Okay so first question is uh oh. I looked on my tercel and it is missing the older standardized axle code too. Mine in the axle portion say 2292. The 292 portion makes sense as its a 2 pinion 4.10 diff. The 2 prefix I have no idea. Perhaps an update to the rule due to the unique 4wd drivetrain?? A code to mark both axles perhaps like 2 x 292?

Now there were lsds made for the 6.38 (s) diffs. TRD made them and recently a friend here in vic got one from Toronto. They are a very good clutch designed unit but rare these days. If you see one on ebay or wherever...buy it!

The 6.7" just will not fit in the tercel housing. The axles won't line up, bolts etc. Its close but not quite.

The toyota celica from 1970-79ish came with a 6.7" rear housing, fourlink set-up, swaybar and drum brakes, open diff. I think its a good candidate. We measured one up at the shop last week and its 53.75" drum to drum. I haven't measured the corolla yet. If you found a gts rear it could work pretty easily too and it comes with discs like you guys seem to like but only comes with stock lsd in the USA. The stock lsd is a piece o crap by the way. Other issue I can't remember if I mentioned is the ae86 diffs have a 4.3 final drive. You obviously need a final drive matching your front diff. Early celicas have some and there are a few suppliers of aftermarket ring and pinions.

The 4 pinion s diff is very common on the 1983-87 corolla rwd sr5. The are quite strong and can be welded nicely by welding the side gears to the diff carrier.

IRS rear? Its been done in some of the ae86 corollas. I even saw a guy who put a Nissan S13 rear in his. Its a lot of fab to do but possible. Too much work for me.


Oh one last thing. If you guys do find a suitable T series diff beware that there are two types, zenki and kouki. This means early or late. Bascally every t series diff from 1970 -1985 is zenki and late 1985 to 1988 is kouki. The kouki axle splines have the same count but are 1 mm larger in diameter. You must NOT put zenki axles in a kouki diff. It will strip the axle.

Man, I have typed way more than I thought I would on this subject, I hope it helps someone.