I bought a 3.5 vlsd a while back and I'm just now taking it to get installed. All those months of reading about how good of an upgrade it was on the forums and the first thing the transmission shop owner tells me, is that I need to change the front differential as well. The guy owns a g35 so I'm gonna take his word for it. But why was this never mentioned in other threads, I always read that people just buy the rear and install it. Am I missing something?

 

The reason you've never heard about this is almost no one that swaps diffs are AWD owners. I don't know the answer for sure but it makes sense that your mechanic is right.

 

I appreciate the reply thanks. I do research my mods pretty decently I'd like to think, https://g35driver.com/forums/g35-coupe-v35-2003-07/349255-3-9-4-08-final-drive-mod.html is just one of the threads I stumbled across where one member states it doesn't matter whether manual (rwd) or auto, I think there should be something stickied in order to warn people. I guess it was stupid on my part but there really was no signs for me. And I can't for the life of me find a front 3.5 differential even being mentioned throughout my Google searches. I just would hate to have to sell this mod, I've had it in my basement for about a year.

 

I'm a G35x owner as well, and have been trying to research this myself. There isn't too much information out about it. I hope that anyone with additional information will be able to add to the discussion.

The way that I have understood from the information available so far is that due to the AWD system and traction control, any limited slip isn't a good way to go. In general, if you lack traction on the right side, the traction control will brake the tire on the right side, allowing the left side to acquire traction. This happens with the open diff, not with an LSD.

Because how these systems interact, I doubt an LSD is feasible in the G35x, although differentials would fit (at least in the rear...maybe the front). I am hoping that I am wrong on this because I would love to do the same thing.

 

The issue isn't LSD or not, it's the gearing. ATTESA ETS PRO has a rear LSD in it.

In any AWD system, you have to take into consideration wheel speed at all 4 wheels. If your gearing is different in the front diff and rear diff, then the wheels are turning at different speeds and that will wreck your driveline.

 

The vast majority of people performing mods to their cars tend to do it to RWD cars, so it's never a concern to mention what's different for the AWD guys. Something you need to be aware of as an AWD owner.

But yes, your mechanic is right, with an AWD car, youd need to change BOTH front and rear differential gearing. Problem with this is:

AWD cars pretty much only come with one ratio up front

amd #2

You'd have to pull the engine out to remove the differential and change the gears.


Simply not worth it, so unfortunately you should just sell off your differential

 

are the actual differntials different between rwd and awd? Could he simply not swap the ring gear off his factory open diff and put it on the LSD?

I'm actually wanting to eventually put an LSD in mine in the future but haven't done any research into it yet. I assumed it was a standard R200 or something across all models since that makes the most sense (hahah...I know...that was a stupid assumption to think they would do something with common sense)

 

Reviving an old thread. I am looking into putting the R200V LSD in my G35X. From my research I can't find a reason why you can't put the LSD in the rear of the G35X, other than threads like this that say "my mechanic says I have to do both or none". The OEM differentials in my car (R200 and F160A) have 46/13 teeth in the drive gear/drive pinion, and a gear ratio of 3.538. These exactly match the R200V from the 6sp manual G35 2005-2006 (sedan) and 2005-2007 (coupe). I confirmed these numbers in the FSM.

I understand the AWD system engages the front wheels when it detects slip in the rear. So with a LSD I would have less slipping in the rear ie. power transferred to the front less frequently. Essentially an LSD swap would make the AWD cars feel more like a RWD car until you really kick out, at which point the front would engage. Ensuring the same gear ratio is maintained in the front and rear diffs will ensure no harm comes to the driveline.

^ This is my current understanding, if anyone has other information or insight, please enlighten me.

 

You can LSD the rear as long as you keep the same gear ratio, it's literally the same differential as the rest of the G/Z cars. Front is a different story, not sure if there are any LSD options for it, also no t sure you would WANT it on the front unless it was just a track car.

 

Yup, if it’s the same gear ratio go for it.

 

I don't want an LSD in the front, just the rear. Thank you for confirming my understanding.

 

I changed the differential fluid this weekend. I have a 2006 G35 coupe with a standard diff (not LSD). The drain bolt magnet collected a gnarly metallic sludge. If you haven't done so in a while, change the differential fluid.

1.5 quarts capacity.

 

Looks like roughly 75k-100k miles between fluid changes. If so that would be a "normal" accumulation of sludge and metal.

 

Got the 3.538 R200V LSD installed into my 2005 G35X last weekend. I had to swap the companion flange from my R200 open differential to the new R200V differential as the driveshafts are different between the RWD and AWD vehicles. Other than that, it was a very straight forward job.

I also installed the Z1 diff bushings and Z1 subframe bushing collars as well (thanks Cleric for the recommendation on the collars). Still have to install my Transgo RE5R05A shift kit. Very excited to see how the car feels in the spring.