AE86 R&P whine...need to set backlash

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karloz

Member
I need some help from the guys who have tackled this job before. My rolla has the dreaded gear whine under load, most likely the crush sleeve has gotten loose and now my backlash is most likely off. "Not You" provided me with a manual (thanks again man!) and I've been looking it over and it looks simple in some steps and like rocket science in others lol.

I need your opinion (the guys who have done it to a rolla or something similar) as to whether this is something I should try myself or have it done by a pro. My wreching skills are average...I've rebuilt a motor, rebuilt brakes, installed trannies, crap like that. But I have never messed with a diff.

I don't wanna give this a try and screw it up worse than it already is lol.
 
Shit, I guess no one here has attempted this scary ass job before lol. On that account, maybe I shouldn't try it either. Anyone know a trust worthy place that will do it without robbing me blind? I called up Spence at Weir Performance, he quoted me 300 for labor only on installing a new ring & pinion, rebuilding the diff in general, and setting the backlash. Which is not bad, but he's in Cali and he's backed up as hell right now. Turnaround time could easily be 2 months.

Also, I was planning on buying one of his spools, but he doesn't make one for the kouki rear, only zenki. Is my only option for a locked diff to weld it then?
The PO told me it had a hellical LSD in it, I heard those suck for drifting, which is why I was looking at spools.
 
When it comes to rebuilding differentials (especially setting backlash) many people consider it an art-form lol. It's something if you plan on doing it take your time and do tons of research on it, until you have a firm grasp on it and the proper tools. That's the best advice I can give you without actually being there in person.

I'm waiting on word from Weir Performance too about other parts they are working on. If your car came with an oem lsd you can always rebuild it ( https://technotoytuning.com/toyota/ae86/lsd-rebuild-kit-ae86-corolla ). If you have an open differential then best bang for buck for a budget drift setup is to weld it, an aftermarket lsd can cost a lot.
 
I agree with you Redline, it looks like it's the kind of thing a novice should stay far away from. I've decided to have a pro, or at least someone who has succesfully done it before, take care of it.

Unfortunately, I don't think I have an OEM LSD in there, the PO told me there's a hellical type LSD, which tells me it's most probably a crappy Ebay OBX. Those are the cheapest LSD you can get for an 86, and they are only 1-way. I was hoping on a spool, but no one makes one for the kouki rears. Another option would have been to grab the 30mm axles and spool kit, but Spence said that they are discontinuing that setup in favor of one that uses 28mm axles for better compatibility, at least that's what I think he said.

So right now it looks like my best/cheapest/quickest option is to source a kouki open diff and have it welded. I imagine those can't be that expensive lol. I'm also gonna pick up a solid spacer kit, rebuild kit, and a 4.70:1 gear set from Weir.

I just need someone to put all that crap together for me...correctly lol.
 
It's really not that hard, but it depends on where the whine happens. I don't remember exactly but accell, decell, mph and in a gear, or nuetral will determine excatly what it is Like too much backlash, too little, inner or outer pinion bearings, carrier bearings etc. changing bearings isnt hard either you just need a press and some fancy removal tools.

As for the backlash you just need to shim it right, The right way to do it is to measure the shims out and there should be a kit or sheet somewhere where it will tell you this thickness shim should add X amount of thousands. Im sure if you google/youtube it you'll find plenty of information.
 
I have the FSM, and I've seen a few vids on youtube showing how to do it but none of those were specifically for a toyota gts rear. I'm sure it's all the same shit but I want to be sure. There's a guy on club4ag that says he's gonna make a write up for it, but hasn't yet.

Tools wise, the bearing seperator and gear puller are cheap from harbor freight, but I still don't have a press. The biggest issue is the fear I have of messing things up.
 
The best I could do searching the web when it comes to this issue. It does say how to rebuild an oem lsd but a lot of helpful information in there none the less. Take a look at the pics in the "Rear Differential Assembly:" section. It's basic but may help with the FSM you have.

http://www.aeu86.org/index/axle-amp-differential-ae86-oem-lsd-rebuild/cat/9/topic=5762/post=78515


Backlash:
http://i4.photobucket.com/albums/y147/assassin10000/AE86 OEM LSD Rebuild/carrierassyfsm3.gif


Parts, part #s and pics:
http://hachiroku.net/forums/showpost.php?p=9&postcount=1
 
It really all depends on what tools you have on hand and how tedious you are, it takes time and lots of patience. If you haven't done it before it could take you 2 months just figuring everything out and then always driving around wondering if your diff is going to blow lol. 300 is fairly good price and you should only have to ship him the third member and that's prolly $70.

I don't know about OBX helicals but helicals in general are pretty rad. LSD required clutch packs that need replacement every so often, helicals don't; LSDs require special fluid for sed clutch packs, helicals don't. Helicals don't need to be warmed up, LSDs do. I would not recommend a spool if you have any intent on driving this on the street, helical will provide you with the ease of an LSD with the aggression of a spool, good for street use and great for track.

Now I also have had a super loud whine from my differential ever since I bought the car. I have a TRD 2 way and it's worked great for the past 4 years of abuse with the 100hp 4AG and trips to PA and back, and the last year with my SR. I've heard that with lower HP AEs people do this to create a snapping effect for clutch kicking making the rear end break out faster/easier also. It really all depends on how much power you plan on making.
 
Thanks for the links Redline, that's all the same stuff I ran accross when I searched myself. Apparently, no one has ever made a write up for this, I've searched for hours lol.

Thanks for the info NY. This stuff is confusing. I've read elsewhere that the hellicals are great for autox and track, but not very good for drifting, specially on cars with live axles. Actually, I think it was Spence himself from Weir Perfomance who mentioned it in a thread I came accross some where. I think the reason was because when the inside wheel comes up and looses traction, you end up with essentially an open diff.

The reason I want a spool or a welded diff is because apart from this car not being a daily, I'm trying to make it as easy to get sideways as possible. Thing is my wife is the real reason I'm getting into drifting. I like it, but she loves it. She wants to learn, but I know how she is, if it proves to be too difficult for her, she'll just quit. At least if it's too difficult at the beggining. So I'm trying my best to make it as easy as possible for her.

I also don't have much power. Car has a 3TC with dual Webers. And they have to be retuned cuz right now I get a bunch of sputtering if I turn hard, they don't like lateral Gs lol.


Not You said:
It really all depends on what tools you have on hand and how tedious you are, it takes time and lots of patience. If you haven't done it before it could take you 2 months just figuring everything out and then always driving around wondering if your diff is going to blow lol.
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Exactly why I don't wanna tackle this myself lol
 
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