So you didn't attach a breather tube to the nipple on the diff then? Did you cap it or just leave it open?

I did nothing to it, just left it. My friend installed it for me, he's a mechanic at Hyundai so I think its safe. Not absolutely sure though

I have a 2004 5at coupe and i wanna drop in the 3.7vsld. Wheres a good place to find one? Who can retrofit it to my G? (New at this.)

Junkyards, Ebay, craigslist, stealership......etc. Just get one from a manual G37 which should have a round flange on the front with 4 bolt holes. It will bolt up without modification.

I know a friend with a manual g37s hes getting the 4.08 gear. It should bolt right in? Even though mines an auto?

It doesn't matter which transmission you have since all G35's have a 4-bolt flange on the front of their diffs while G37's have 2 different versions, a 3-bolt and a 4-bolt flange. That is what you need to look out for. Any OEM diff with the 4-bolt flange can be bolted on directly. The other ones would need the flange swapped out and the pinion shaft shortened.

Well i need some sort of schematic for the 2008 g37s 6mt coupe then. Thats wat he has.

So I picked up this diff in January and debated whether or not to do this mod because of the discussions on here about the cruise and my own personal concerns about gas mileage and general wear due to increased rpm. I decided a few weeks ago to go ahead and put it in thinking the worst that that could happen is I wouldn't like it and I'd have to put the original back or get a 3.5 vlsd and swap that in. For those of you that read this whole thread and still have concerns about this, don't. The only unexpected issue I experienced during the install was you have to change the collar on your old yolk to the one on the 3 bolt yolk, use a big socket to press it on. The OP tried to cover this in this diy, it just wasn't clear. My cruise works at least up to 80, I haven't tried it any higher and never use it above 80 anyways so that's not an issue. On my last tank I averaged 21.8 mpg, with the stock diff I never averaged over 21mpg, usually I was right around 19-20mpg. The rpm doesn't seem to be a factor even on the highway cruising at 80 the added 500rpm are hardly noticable in the cabin, there's no extra vibration or engine noise, time will tell but I figure if it's getting better mileage it's more efficient which in turn means it's not really working any harder This is a great mod for the 5at.

I'm guessing that's a 3.7? And you didn't have to shorten the input shaft?

It's a 3.7 vlsd, I assumed everyone would figure it was a 3.7 since it's in this diy. I did have to shorten the pinion and swap the yolk from the original diff once the collar from the 3.7 was fitted.

Bump! So I have the question if I use my stock diff that's in my 06 coupe and I buy a 3.9 final drive gear sold by Z1 which is only for the manual g35. An cut it to fit my automatic coupe. Or do I have this backwards in thinking the manual is longer then the automatic.

The different length driveshafts is because of the transmissions, not the differential. I don't know much about the internals of the diff but you're better off buying the correct kit.

sorry to bump a old thread but has anyone here tried to put 3.90 gears in a 5at 2007/2008 3.69 g35 differential

I've read so much over the last week on this install Im going crazy.

I have a 03.5 G35S AT5 with the factory diff 3.3 with a 4 bolt flange. So I need to go to a 08-09 MT Sedan Pumpkin that has the 4 bolt flange and no extra Moda need to be done correct? To do this install I will be traveling 30 miles to a friend's house on my off day (He has the tools/skills) and all is well. The only issue would be using my old abs sensor rather than the ones in the new pumpkin. There are so many different info DIY on this swap. The guys who had to swap yolks, shorten pinion shafts are coupe guys or non 03 sedan guys correct. Im pulling the plug on a Pumpkin to do this install September 26th so I need to know. If an extra part is needed I gotta pray dabbing can be done or my car will be stuck 30 miles away from home.

No the guys that had to shorten the pinion shafts bought the auto 3.69 diffs. The manual 3.69 diffs are a direct swap.