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MountainBiker

04 STI LSDs fit 4EAT Forester?

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You can use any rear LSD you want with any transmission as long as you use the ring and pinnion from that transmission.

 

The front however, no idea... I'd like to know as well.

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i remember reading over on nasioc that you cant use the STI stuff in the other non-STI trannys, something about size or something. butdoesnt kaaz or cusco make a front lsd for the wrx? if they do, you could put that in.

 

 

~Josh~

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Front and rear STi diffs (6MT) will NOT fit 5MT or 4EAT Forester.

 

why?

 

Front:

The SureTrac and Helical 6MT front diffs are much narrower than the 5MT and 4EAT front diffs. They will not drop in. MUCH custom machining to be done to make it fit correctly.

 

IF the front diff carrier unit in the 4EAT is the same as all the 5MT 4WD/AWD transmissions...then go get a Helical or clutch type front LSD for your average WRX (pre 11/2003 production date) or 2.5 RS, or 5MT GC8/GF8 WRX/STi.

 

Rear:

The STi's have the R180 rear diff. Everything else has the R160 (including the ALL of the Gen1 Gen2 and Gen3 EA cars)

 

the R180, while VERY similar in external size, its only about 1 inch taller, and bolts right up to the driveshaft and diff mounting...the axles are the difference. The axles for the R180 are MUCH larger. You will have to get some custom axles made up. I have tried to make hybrid axles taking R180 peices and trying to make them work on R160 axles and vice versa....NONE OF THEM INTERCHANGE. Custom axles will have to be manufactured. IF you get the axles, then you can use it.

 

HOWEVER...the stock STi rear diff is a PEICE OF JUNK! It doesnt work at all. Its a DOWNGRADE to install one in place of a VLSD, and a DEFINATE stupidity move if you replace the R160 clutch type with the STi rear diff.

 

the ONLY reason I would EVER consider installing an R180...is if I were going to be rally/drag/roadcourse/autoxing with oever 800 hp to the ground. The R160 can take whatever you throw at it, even up to that power level. Its perfectly fine. Go get a Kaaz/Cusco/stock RX rear clutch type for R160 and install that. MUCH less PITA work and you will get desired results.

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Thanks for the replys. STI LSDs can be found cheap, that is why I was asking.I suppose I'll be looking at the OBX front LSD, but haven't read too much feedback on those.

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Thanks for the replys. STI LSDs can be found cheap, that is why I was asking.I suppose I'll be looking at the OBX front LSD, but haven't read too much feedback on those.

 

Its a helical. If you've ever driven an 05 or 06 STi...you will know those are worth their weight in gold.

 

the 04 STi and all the JDM Version 7 and version 8's ahve the SureTrac...its nowhere near as good as the helical.

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doesnt the STi have a Porshe tranny??

 

Does the STi do 147+ in reverse? No.

 

It is NOT a Porsche transmission.

 

There are still a number of 6MT parts that interchange with the 5MT....

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