Zenki or Kouki Rear End

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RLZ
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Zenki or Kouki Rear End

Postby RLZ » Sun Dec 01, 2013 6:55 pm

Hey guys, my car is kouki corolla gts, my current rear end is non LSD and it making noise, I think it's from the wheel bearing and inside the diff, also I bought a zenki LSD rear end with replaced wheel bearing few months ago it needs adjust the back lash which pervious owner told me. I have 2 choices, one is replace the bearings and get a aftermarket LSD on my kouki one, another is adjust the back lash and put the aftermarket LSD in the zenki one. What do you guys think about this? Give me some suggests thanks!
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Re: Zenki or Kouki Rear End

Postby Spoold86 » Sun Dec 01, 2013 10:59 pm

:roll: well, zenki rear ends seem to be a little easier to come by

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Re: Zenki or Kouki Rear End

Postby RLZ » Sun Dec 01, 2013 11:28 pm

Spoold86 wrote::roll: well, zenki rear ends seem to be a little easier to come by


Do you mean rebuild kits?
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Re: Zenki or Kouki Rear End

Postby gotzoom? » Tue Dec 03, 2013 9:25 am

Backlash is not something you "adjust." It is set precisely when the carrier is assembled. If it is out of spec, it means that something wore out (bearing[s] and/or crush sleeve) and your ring and pinion will likely howl. Even if you get everything back in spec, it will likely always make noise, since the wear on the gears is not in the right place. If it's an original factory LSD, it's also probably dead and in need of a rebuild.

Since the zenki rearend is off the car, I'd probably crack it open and see what things look like inside. Rebuild parts are the same for zenki and kouki and the rearend housings are functionally identical, so you could easily get the zenki stuff working properly and swap carrier and axles over. That would allow you to leave the brake lines untouched and save you having to bleed brakes. Your downtime would be minimal this way too.

Personally, I'd sell the zenki rearend and buy a new Tomei diff and do a fresh rebuild on the kouki carrier, assuming the ring and pinion are in good shape. The only way to find that out is to remove the carrier and see what's going on in there.

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Re: Zenki or Kouki Rear End

Postby RLZ » Tue Dec 03, 2013 8:37 pm

gotzoom? wrote:Backlash is not something you "adjust." It is set precisely when the carrier is assembled. If it is out of spec, it means that something wore out (bearing[s] and/or crush sleeve) and your ring and pinion will likely howl. Even if you get everything back in spec, it will likely always make noise, since the wear on the gears is not in the right place. If it's an original factory LSD, it's also probably dead and in need of a rebuild.

Since the zenki rearend is off the car, I'd probably crack it open and see what things look like inside. Rebuild parts are the same for zenki and kouki and the rearend housings are functionally identical, so you could easily get the zenki stuff working properly and swap carrier and axles over. That would allow you to leave the brake lines untouched and save you having to bleed brakes. Your downtime would be minimal this way too.

Personally, I'd sell the zenki rearend and buy a new Tomei diff and do a fresh rebuild on the kouki carrier, assuming the ring and pinion are in good shape. The only way to find that out is to remove the carrier and see what's going on in there.


I don't think the ring and pinion are good on my kouki one, I might upgrade the final drive if I ever decide to renuild the diff, on your option you would keep the kouki and rebuild it, how much do you know to rebuild it and replace wheel bearings? Also I have to get the LSD and final drive, I really don't know which is a best final drive on daily.
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Re: Zenki or Kouki Rear End

Postby gotzoom? » Wed Dec 04, 2013 9:10 am

I guess it really depends on whether you have another car to drive daily. If you do, you have a lot of options. If not, I think you're forced to get everything replaced and do the swap in one day. I guess it doesn't matter if you plan to take the car to a shop to have the work done, though.

Personally, I feel the 4.3:1 gearing is perfect for the T50 transmission for road and track use. At 70mph on the freeway, the car isn't obnoxious to drive and the revs are in the fun zone, so you can step on it and pass someone if you need to. On the tracks around here, I am not in between gears in many places, and the plaaces that I'm in between gears are not super costly in terms of time loss.

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Re: Zenki or Kouki Rear End

Postby RLZ » Wed Dec 04, 2013 9:24 am

gotzoom? wrote:I guess it really depends on whether you have another car to drive daily. If you do, you have a lot of options. If not, I think you're forced to get everything replaced and do the swap in one day. I guess it doesn't matter if you plan to take the car to a shop to have the work done, though.

Personally, I feel the 4.3:1 gearing is perfect for the T50 transmission for road and track use. At 70mph on the freeway, the car isn't obnoxious to drive and the revs are in the fun zone, so you can step on it and pass someone if you need to. On the tracks around here, I am not in between gears in many places, and the plaaces that I'm in between gears are not super costly in terms of time loss.


I don't have an other car it's my daily, I think I will let the mechanic prepare everything so I can drop it in one day :lol:
Where can I get the 4.3:1 do you know any?
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Re: Zenki or Kouki Rear End

Postby herro » Fri Dec 06, 2013 12:10 am

4.3 well is in every gts diff.

I am sure you can source a used one cheap or weir does have new 4.3

I have personally ran zenki kouki and celica.

I have an f20c none of them ever blew up unless you hard clutch kicking. Even then most of the time your R&P would go first due to the crush sleeve getting all loose.

If your going to rebuild I recommend getting an lsd since you might as well upgrade and a solid spacer.

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Re: Zenki or Kouki Rear End

Postby RLZ » Fri Dec 06, 2013 10:53 am

herro wrote:4.3 well is in every gts diff.

I am sure you can source a used one cheap or weir does have new 4.3

I have personally ran zenki kouki and celica.

I have an f20c none of them ever blew up unless you hard clutch kicking. Even then most of the time your R&P would go first due to the crush sleeve getting all loose.

If your going to rebuild I recommend getting an lsd since you might as well upgrade and a solid spacer.


Even the open diff has the 4.3? What about 4.5 anyone has experience with it? if you were me what you gonna do in this situation? I wanna spend less money with better result :)
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Re: Zenki or Kouki Rear End

Postby Mr.Fujiwara » Tue Dec 10, 2013 1:16 pm

I Run a TRD 4.733 final gear on my Stock Zenki LSD
and i love it i daily it and i have no problems what so ever
a bit noisey after 80 MPH on the hightway but i usually cuise
at about 70 and no obnoxious noises
Old username: Charskiezz

20V BT: Traded For F20c Swap

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Re: Zenki or Kouki Rear End

Postby RLZ » Wed Dec 11, 2013 11:24 am

Mr.Fujiwara wrote:I Run a TRD 4.733 final gear on my Stock Zenki LSD
and i love it i daily it and i have no problems what so ever
a bit noisey after 80 MPH on the hightway but i usually cuise
at about 70 and no obnoxious noises


What gas mileage you have? :shock:
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Re: Zenki or Kouki Rear End

Postby Deuce Cam » Wed Dec 11, 2013 12:54 pm

My car has 4.778 final drive on a stock 16v and I get about 25/30 mpg city/highway. IMO it's quite loud at 65+ mph on the highway since the engine is above 4k rpm. I wouldn't recommend it for a daily driver.

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Re: Zenki or Kouki Rear End

Postby RLZ » Wed Dec 11, 2013 1:17 pm

Deuce Cam wrote:My car has 4.778 final drive on a stock 16v and I get about 25/30 mpg city/highway. IMO it's quite loud at 65+ mph on the highway since the engine is above 4k rpm. I wouldn't recommend it for a daily driver.


whats the different between the 4.733 and 4.778?
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Re: Zenki or Kouki Rear End

Postby Deuce Cam » Wed Dec 11, 2013 3:12 pm

They're so close it would be hard to tell the difference between them.

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Re: Zenki or Kouki Rear End

Postby RLZ » Wed Dec 11, 2013 5:57 pm

Deuce Cam wrote:They're so close it would be hard to tell the difference between them.


I see, Im still not sure take kouki or zenki :x final drive choice not a problem tho
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Re: Zenki or Kouki Rear End

Postby phanist » Thu Dec 12, 2013 12:19 am

I got the weir 4.778 final drive R&P
Yah it a bit nasty for daily.
But my opinion it pick speed a bit faster.
In 5th gear freeway it not good... Unless u have Mfactory 5gear...
Which what i have on my tranny along with my trd gear set..
So far i love it. Freeway cruising now at a lower rpm.. Less engine sound..

Sorry for off topic

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Re: Zenki or Kouki Rear End

Postby RLZ » Thu Dec 12, 2013 8:29 am

phanist wrote:I got the weir 4.778 final drive R&P
Yah it a bit nasty for daily.
But my opinion it pick speed a bit faster.
In 5th gear freeway it not good... Unless u have Mfactory 5gear...
Which what i have on my tranny along with my trd gear set..
So far i love it. Freeway cruising now at a lower rpm.. Less engine sound..

Sorry for off topic


oh I see, how much for the Mdactory 5 gear? will it work on a stock tranny?
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Re: Zenki or Kouki Rear End

Postby Deuce Cam » Thu Dec 12, 2013 8:42 am

^I don't think you can get them anymore, but I have one fs that I never used. $400 shipped. It's a direct replacement on the stock transmission.

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Re: Zenki or Kouki Rear End

Postby phanist » Thu Dec 12, 2013 10:33 am

Cant remember the exact price but. It in the 350--450$ range.. And i think one of the member here know how and who to contact for that matter... I think the supply for that it limited. The person that sold me that gear said it just have a couple set left.

Yes it will work with stock gts t50..
That was what i originally doing but end up spend about 2000$ for the trd gear set shipped from JP
Let me check my old email to see if i can still find him.

But it work nice for me... Love it

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Re: Zenki or Kouki Rear End

Postby phanist » Thu Dec 12, 2013 10:45 am

Here is his email i think
Samekkha@gmail.com

250.415.3424

His contact number? Im not sure... But found those in email.

Good luck
Hope those info help who ever want to find that mfactory 5th gear

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Re: Zenki or Kouki Rear End

Postby RLZ » Thu Dec 12, 2013 11:05 am

phanist wrote:Cant remember the exact price but. It in the 350--450$ range.. And i think one of the member here know how and who to contact for that matter... I think the supply for that it limited. The person that sold me that gear said it just have a couple set left.

Yes it will work with stock gts t50..
That was what i originally doing but end up spend about 2000$ for the trd gear set shipped from JP
Let me check my old email to see if i can still find him.

But it work nice for me... Love it


Thanks for the info, why you replaced with TRD gears? You just upgrade or you have some issues with the Mfatory gear on stock one? Also what's the other issues if I run the 4.7 final drive on a stock tranny except the noise? will that shorten the engine life since high rpm on freeway?
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Re: Zenki or Kouki Rear End

Postby phanist » Thu Dec 12, 2013 11:16 am

Uhn...
In my experience i change the 5th gear to mfactory in the 1st because i want to save gas and run low on freeway
No issue except for that.. It free more aggressive. But that why u install the 4.778 in the first place right?.
As for noise it all come down to your setup header to exhaust etc... Not noise from rear end... Noise cause by rear end it a different topic... That it depend on the person who setup your R@P in the rear end... Guru please do correct me on that....

Trd gear set ..... I order mfactory before i got the trd gear... But choose to install them all at once since it a pain to do it twice. And costly if u have a pro to install.
But mfactory 5th gear was intended for the stock t50 tranny i believe or was told...
But it work well with my trd gear set...
I cant see why it wouldnt since both were made for the t50 tranny to begin with.

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Re: Zenki or Kouki Rear End

Postby Deuce Cam » Thu Dec 12, 2013 11:34 am

I think the national speed limit was still 55 mph when these cars were released. That combined with the fact that the 4a has very little tq. is probably why Toyota geared 5th so short on these cars. Even a stock gts is up near 4k rpm at 65-70 mph.

The mfactory 5th gear will allow a lower cruising rpm at freeway speeds on any ae86.

The mfactory 5th combined with a 4.7 final drive is supposed to lower the highway cruising rpm close to what a completely stock gts experiences. That way you still get the punchy acceleration in the lower gears, but 5th gear feels basically stock.

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Re: Zenki or Kouki Rear End

Postby RLZ » Thu Dec 12, 2013 12:54 pm

Sounds like Mfatory 5th with a 4.7 final is pretty good match up, I would like to get that if I have enough of fund :lol: . But back to first point, a stock LSD zenki and the open diff kouki rear end which one you would choice to work on, the kouki needs wheel bearings but the zenki doesn't.
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Re: Zenki or Kouki Rear End

Postby Deuce Cam » Thu Dec 12, 2013 2:03 pm

^Zenki seems like the best option then; less work and it already has lsd. The only benefit kouki provides is the axle shafts are about 1mm larger in diameter at the splines.

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Re: Zenki or Kouki Rear End

Postby RLZ » Thu Dec 12, 2013 3:33 pm

Deuce Cam wrote:^Zenki seems like the best option then; less work and it already has lsd. The only benefit kouki provides is the axle shafts are about 1mm larger in diameter at the splines.


Let's forget the LSD at this point, I will get an aftermarket LSD anyways. Will the bigger axles make much difference? Also what brand of final drive you guys running? I saw T3 has some but I don't see any ppl running them.
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Re: Zenki or Kouki Rear End

Postby Deuce Cam » Thu Dec 12, 2013 3:38 pm

It's only a 1 mm difference so it's pretty negligible fwiw; it's not going to make much difference.

Mine is oem Toyota. Weir performance also has a few different ratios available for a more affordable price.

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Re: Zenki or Kouki Rear End

Postby RLZ » Thu Dec 12, 2013 4:08 pm

Deuce Cam wrote:It's only a 1 mm difference so it's pretty negligible fwiw; it's not going to make much difference.

Mine is oem Toyota. Weir performance also has a few different ratios available for a more affordable price.


I see, Toyota make 4.7 gears also? What do you think 4.5?
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Re: Zenki or Kouki Rear End

Postby Deuce Cam » Thu Dec 12, 2013 5:26 pm

http://club4ag.com/tech-specs/ae86-fina ... t-numbers/

4.5 would probably be a good compromise between 4.3 and 4.7. I've never tried it though.

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Re: Zenki or Kouki Rear End

Postby RLZ » Thu Dec 12, 2013 6:16 pm

Deuce Cam wrote:http://club4ag.com/tech-specs/ae86-final-drive-differential-gears-and-part-numbers/

4.5 would probably be a good compromise between 4.3 and 4.7. I've never tried it though.


How much you paid for it from Toyota? I bet not a good price :roll:
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