Help Identifying Rear Diff

[Timtim123]

Hello, new member here. I'm in the US and as you know, Skylines are just becoming legal here and I was able to scoop one up. I'll admit, I'm not super knowledgeable with the ins and outs of these cars and come from the Subaru world prior to this. Anyway, I purchased a 90 gts-t and was told that the rear diff is pretty aggressive although the importer couldn't tell me what it was. It doesn't seem to be welded going off of my limited knowledge. However, it's pretty annoying honestly (very loud and rough around turns) and I don't plan to track the car or do much more than regular driving, so I plan to just grab a stock rear diff instead. I was hoping to find out what diff is currently on the car though to ensure no strange swaps involving the driveshaft and such were done so I know that what I purchase will fit. Not expecting anyone to know what's going on inside the casing, but rather just want to know if this is a r32 gtst diff or if it looks swapped. Looked at a good bit of photos of others for sale trying to match one up but not having a ton of luck.

I've attached a couple of photos I was able to grab when looking under the car. If any additional photos or info would help in identifying, please let me know and I'll follow up. Appreciate any help!

[Hadouken]

You have to open her up and get a picture of the centre. It might very well be welded.

If you don't want to open it up change the oil and see if it helps.

[Timtim123]

You have to open her up and get a picture of the centre. It might very well be welded.

If you don't want to open it up change the oil and see if it helps.

Thanks for the reply. Even if it's just welded, I'll likely replace it. I'll just be using the car for regular cruising. Just wanted to see if it was a standard r32 gtst casing before I ordered something to ensure it'd fit (in case the previous owner replaced it along with driveshaft or something weird like that. Parts aren't cheap and easy to come by here, so wanted to make sure I am getting the right thing.

[GTSBoy]

It's just a standard casing. No-one would ever normally bother to change that on an R32. The diff itself will most likely be an aftermarket 2-way mechanical. Again because almost no-one would bother welding one when mech centres are readily available and not too expensive. The good news is that a decent mech diff sells for $500-$1000 2nd hand. So you might come out of this with money in your pocket if you can locate a stocker.

FWIW, the stock VLSD is a piece of shit and you will hate yourself if you install one. Single spinners suck dogs' balls.

[Timtim123]

It's just a standard casing. No-one would ever normally bother to change that on an R32. The diff itself will most likely be an aftermarket 2-way mechanical. Again because almost no-one would bother welding one when mech centres are readily available and not too expensive. The good news is that a decent mech diff sells for $500-$1000 2nd hand. So you might come out of this with money in your pocket if you can locate a stocker.

FWIW, the stock VLSD is a piece of shit and you will hate yourself if you install one. Single spinners suck dogs' balls.

Awesome, thanks. Yeah whatever it is, it's pretty damn rough when doing slow turns. Rather than some wheel squeal and drag, it's more like a clunking and rough drag, almost feels and sounds like the car is just broken. Either way, I'm not a fan and likely don't need it so if I can locate another option for a good price, whether it be a stock one or something much less aggressive, I'll be happy and will crack this open to see what it is and maybe sell to someone who does want it.

[hardsteppa]

that's funny, what you describe is a mechanical diff centre in action. Agreed it's not particularly gentle but as above, if you fit a standard vlsd you'll like cornering and driving in general ALOT less, the mechanical lsd rocks for any kind of performance driving over the stock unit. Here in aus 2ndhand vlsd complete diffs go for about $2-300 so you'd definitely be able to get ALOT more for your mechanical centre if you decide to swap it out.

[Timtim123]

Would this type of diff make sense for sone one that is trying to drift the car? I ask because some of the other mods on the car suggest that is what the previous owner was going for

[Hadouken]

He was probably a hard core drifter.

[hardsteppa]

wouldn't have to be drift, a lot of people who own skylines modify them in a similar way. Before you ditch the mechanical centre, you could check the settings and adjust it most likely to make it more street friendly. Eg set it to 1-way, not 2way, alter the order of the clutch plates to make it lock less harshly.

[GTSBoy]

Eg set it to 1-way, not 2way, alter the order of the clutch plates to make it lock less harshly.

Assuming those things are possible. Some diffs can, some can't. Either way, a trip to a good driveline/diff shop sounds like it's in order.

[hardsteppa]

tht's why I say "adjust it most likely" . Because some can't, some can. But it's not that hard, OP how handy with a spanner are you?

[Timtim123]

I'm pretty good mechanically. Between my brother and I we've tackled just about all maintanence and work to our cars ourselves including some decent builds, fab, paint, etc. Don't have much drivetrain experience though but nothing I likely couldn't figure out. Maybe I'll just crack it open in the near future and see what I'm working with and go from there if I can find some decent how-tos. Currently I'm tackling some rust in the trunk and will be dropping the fuel tank, cutting, and welding new pieces in this weekend hopefully. Luckily my brother runs a laser cutter (not sure the proper name) at my uncles shop and can shape and bend up the pieces for it.

Appreciate the help and info so far!

Edited September 3, 2015 by Timtim123

[GeeDog]

On the off-chance it's a Custco diff, this article shows how to tune the diff:

http://www.motoiq.com/MagazineArticles/ID/2966/Project-370Z-Improving-Grip-by-Tuning-a-Cusco-RS-LSD.aspx

[Timtim123]

On the off-chance it's a Custco diff, this article shows how to tune the diff:

http://www.motoiq.com/MagazineArticles/ID/2966/Project-370Z-Improving-Grip-by-Tuning-a-Cusco-RS-LSD.aspx

Awesome, thank you. If I cracked open the casing, are they usually pretty clearly labeled, as far as brand and such? I'll prob look into it once I finish some of the bodywork.

[GTSBoy]

If I cracked open the casing, are they usually pretty clearly labeled, as far as brand and such?

No, they're usually not. You will need to do some googling and looking at various manufacturer's sites and there are also many threads on here you can use for reference. Many have no markings at all. By looking at different photos you can usually get close to working out whether it's Nismo or Cusco or one of the other options, as they do look a little different (where they are machined, where they are not, shapes of the openings, etc). You will also be able to work out if it is 1-way, 1.5-way or 2-way if you know where to look and what to look for. Again, this has been discussed on here heaps, so there's plenty of info to help you. At the very least you can take a bunch of GOOD QUALITY HIGH RESOLUTION photos and post them up if you need a second opinion.