Yes, I searched (been reading all morning).

I think I'm going to pull the trigger and get the 3.9 gears (getting a good deal on a new set of 350EVO gears that someone didn't end up using) done on my '03 Track and had a few questions:

1. is there a recommended breakin period that the diff fluid should be changed after swapping to new gears?

2. for those that have 3.9 gears, do most get a diff, too or just put them in with the stock VLSD? It'd be nice to slap a Cusco RS in there at the same time (I know the labor wouldn't be much more), but I just can't afford it. I don't track my car; just spirited driving, but not at limit and don't hang it out... thinking a diff may be overkill for me, anyway?

3. Does ANYONE have the Nismo diff cover in stock yet???



That's it. At lkeast I'm not asking what parts I need for install, do I need a reflash, what'll my top speed be, will I see result on the dyno, will my gas milage go down, where/how much for install, etc...

 

1. is there a recommended breakin period that the diff fluid should be changed after swapping to new gears?
1200 to 1500 miles of easy cruising.

2. for those that have 3.9 gears, do most get a diff, too or just put them in with the stock VLSD? It'd be nice to slap a Cusco RS in there at the same time (I know the labor wouldn't be much more), but I just can't afford it. I don't track my car; just spirited driving, but not at limit and don't hang it out... thinking a diff may be overkill for me, anyway?
If that's the case, stick with the stock VLSD.

where/how much for install, etc...
It's completely variable on where you live and who you take it to.

 

1. ^What he said

2. If you can't afford it don't buy it. But if you can you might as well to the install at the same time. Based on your application above OEM VLSD should be fine, but upgrades are always fun.

3. Darren from Intense sold me mine about a week ago. It was one of two he had access to and the other one sold to streetd. You can check with Darren to see if he can get any more. I'm pretty sure they are on backorder with most of the other vendors, but that could have changed recently so shop around.

I'm doing the same... but Central20 3.9, Cusco 1.5, and Nismo Finned Diff Cover.

 

How does it work with the shims when you take it to a shop to install? Do they figure out what is needed and get them from Nissan or would I need to provide them or what? I'd rather not have to buy a whole set...

 

From what I gather Nissan only sells them in sets and they are about $200... some shops that do this work frequently will have some on hand they can use and not require a whole kit. This is also a good reason to go with a dealer if you can find a decent one.

 

My dealer sells individual sized shims. I'm sure they all would. Your installer will measure what you need.

pp

 

Hmm, maybe I'll heck with my local Infiniti dealer to see if I can get my old tech there to do it; I know him and the service manager pretty well from when I had my G35 and FX35... Otherwise, I guess I'd have to be on hand during the install to make a run to Nissan for the proper shims.

How long does the install take?

 

The shims for the differential should be the same and available from either an infiniti or nissan dealership. However, depending on whether they do differential work at all above RE and RE work on pumpkins, the may not stock the shims and/or have the tools to do the job. My dealership was keen to do the work, but in the end declined as they didn't want to purchase the special service tools for a job they "may never do ever again". They did quote 5-7 hours for the job for me prior to declining. Best to talk to your contact at the dealership as they obviously would be able to give you a direct answer on their capabilities.

pp

 

Dealer didn't want to mess with it for the obove reasons. Found a gear shop that specializes in rear ends and was quoted $300 if I take them the pumpkin. Price was nearly double if I just took the car, so I think I'll do a little grunt work in my garage and save some cash. Owner/operator I talked to said he had pretty much any shim imaginable; sounded like he knew his stuff.

 

As for the shims, if you re-use your VLSD, you will not need side shims.

However, since you are mounting a new pinion gear, you may need the pinion height shim to get the right gear lash. In any case, the shims are easy to come by and pretty cheap.

To do a really good job, two new pinion bearings and two new side bearings should be used if you have 40-60K miles or more. Some say 30,000, but I think this is a little early.

 

Yeah, I have under 30k miles, so I'm just doing the pinion oil seal, crush washer and nut.

 

Bump for update?