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Front diff interchangeability: The true answer


WJM
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PG makes a front diff for the autos...

 

The auto diff vs. the 5MT diff is different and will not interchange...so use the PG unit for the autos.

 

For your GL10 the front diff that I am using, will work for any 5MT 4wd you put in there.

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so you got a helical Diff???? DO YOU HAVE MONEY LAYING AROUND???? if you dont mind me asking(if you do then just say so or you can PM me) How much did it cost... helicals are chumpchange!:grin:

and im thinking of doing a 2.5 swap way later in the future... one of those would well... wait stupid question because i would definately swap drivetrain along with it..... never mind!

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Are these front diffs from the R series? You know, the rears are R160's Nissan's mostly have R180's, and so on. I've heard the front diff isn't a R160, but is it still an R??? And if so, an Rwhat?

 

I'm gonna have to keep an eye out for your future posts WJM. Sounds fun so far.

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the front and rear diffs are completely different, not compatible at all.

I know that. I was just wondering if a R180 was the same.

 

The way I heard it on the Datsun sites is the R in R160 ment it was made by fuji. But you say otherwise?

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No. Not at all. R is simply a designation.

 

One would think that since the R180, 160 and 200's are all REAR diffs for JAPAN mfg cars...that R would stand for "REAR" and the 160 180 and 200 numbers would stand for ring and pinon sizing or different power handling ratings....

 

R160 and 180 internals differ very much so. About the only thing the R180 and 160 share are the bolt up patterns. Otherwise, driveshaft and axles are different. However, the front driveshaft peice between 160 and 180 will interchange to allow useage of the STi 6MT driveshaft install inplace of the 5MT when converting an Impreza to 6MT if using the R160 with a 3.90 R&P set.

 

NONE of the rear diffs would work at all in place of the front.

 

Neither of those units share similar dimensions of any sort.

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  • 1 month later...
its not in MY RX yet.

 

Many others with subarus are running it with no problems.

 

So what I am getting from this thread is that there will be much better traction in the front now in response to the rear? AKA lower understeer? What are the benefits specifically (no need for laymans terms:grin:)?

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Its $450 shipped. The front diff works in all 4WD 5MT's from 1985 to 2004.

 

Do you have a URL to the site where you got the LSD? I'd love to give it a try.

 

Second, have you considered producing a repair manual for making the swap? I, for one, would love to see what's involved from beginning to end.

 

Thanks,

BB

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Phantom Grip.

 

 

As for laymans terms..

 

on throttle push is greatly reduced.

 

very interesting indeed. This will have to be done down the road after im done with the suspension re-tool. Anything to improve my grip against the unlimited amount of WRX, STI, and EVOs out here :brow:

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From what I can see from pulling apart a couple of subie gearboxes it would be super easy.

 

Unbolt the back plate form the rear of the gearbox.

Unbolt the center diff housing, I needed a little force to get the diff splines off.

Split the gearbox casing apart.

Pull the front diff out.

Unbolt the crown gear/ring gear off the diff.

Bolt the LSD unit to the ring gear.

Play around with shimming for a few hours. (I'm sure you can look on google for "how to shim an LSD")

and then do the reverse of what I said above.

I may of missed something, like maybe putting the stubs on the LSD unit if it doesn't already have them, but I'm sure any one could be able to figure out what needs to be done. Just mostly circlips holding things together in there by the looks of it.

 

Like WJM says, it's easy. And if aren't sure you can do it, maybe you shouldn't.

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I'd say it would be rather helpful, as you're dealing with gear preload, it wouldn't be a bad thing to have a FSM handy.

 

Nah...;)

 

Tho, I will take it back. Case bolt TQ values and the measurements for the shift forks are very important.

 

Really, the only good gear backlash explanation is in the early 3AT books...the 5mt, 6mt, 4EAT, and D5AT books are horrible at explaining the gear backlash.

 

very interesting indeed. This will have to be done down the road after im done with the suspension re-tool. Anything to improve my grip against the unlimited amount of WRX, STI, and EVOs out here :brow:

 

Those cars definatly dont have an unlimited amount of grip.

 

Lets face it, the WRX is weaksauce.

The EVO is only slightly better, until you get an EVO 9. More on this later.

However, the STi is 3 levels of status.

 

The 04 is fast.

The 05 is faster.

The 06 is fastest.

 

The 07 is untested...with less caster, better gearing, a Torsen rear diff, improved ECU dynamics, and a different stock turbo...it may prove to be better than the 06. But after driving almost anything you can imagine from 04 to 06...the 06 is best, by FAR.

 

With the normal WRX...in stock form, they are a rather poor excuse for a performance car. However, they are EXCELLENT in the market corner that they are in: a sporty, economical 4 door. However, when pushed hard, the EJ205 is weak. The 5spd will not put up to the average person's abuse unless you sink $6k into putting PPG gears into it, and on top of that...the open front, viscous center and WEAK-A$$ VLSD rear promotes terminal understeer. Fix the front and rear diffs, 70% of the push goes away right there. Setup the suspension, possibly change the center, and you can get very acceptable handling for a PERFORMANCE sports car...like the STi. But then you overpower the brakes with the enormous weight....etc etc etc... The 06+ WRX is a much better step. Brakes, AL susp. parts, EJ257 w/AVCS...etc etc...However, small TMIC, small turbo, and still a 5spd. :-\ Still weaksauce to me.

 

As for the EVO....the EVO 8 and EVO 8-MR is a COMPLETE letdown. 03-04's has open front diffs, a clutch type rear that was a step above the JUNK in the 04-06 STi...but unless you did something stupid....it was terminal understeer on throttle. IIRC the 05's got helical fronts and active center diff....like the MR...but the MR's that I've driven were worse than the normal ones and the RS's. Laggy, pushy, twitchy....and its still just a Lancer with a turbo and 4WD.

 

However...the EVO 9 is....is completely what the EVO 8's should have been.

The MIVEC (Mitsu's version of AVCS) makes the boost instant like an STi, the diffs do what they SHOULD do...so, the car feels MUCH better. Nearly zero lag, very neutral (point and GO!)...and with NICE leather seats. A MUCH better Lance with a turbo and 4wd. :lol:

 

 

The point of all that...the cars have a ton of grip, but you have to massage them to get even more. And in the end...you spend alot of money on them to make that massive grip over stock.

 

Even before all the intensive suspension work on my RX...and definatly before the diffs were a though...I had no problems running down stock STi's/EVOs/WRX's...even lightly to moderately modded ones. When it came to ones with high HP levels, I could only keep up in areas that the larger turbos could not get to full boost, at that point I was all over them and either passing to letting them get some distance.

 

Now, with 100% more developed suspension, the 2 new diffs, and ATLEAST 300 at the wheels...I am sure that I'll be able to outrun anything in the $40,000 to $80,000 range on a road course. :burnout:

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