[phil280zxt]

I need some clarification on R200 differentials. I am in the process of collecting parts to convert my 1981 280zxt from auto to a 5 speed. The plan was to also convert the 3.54 diff to a 3.9 diff using the same half shafts.

When I recently purchased an R200 from what I was told was a 1982 5 speed 280zxt. I innocently assumed that all 280zx R200's were the same other than the gearing and the drive shaft flange and thought this would be an easy bolt on.

However, this weekend I was under my car and noticed that my 3.54 does not have the four bolt half shaft flanges like the 3.9 diff I purchased. Are these the CV halfshafts that I have heard mention of ?? My 1981 FSM turbo supplement shows that the half shaft ends on my car are inserted into the differential rather than bolted onto flanges. What are my options??

Thanks for the help,
Phil

 

[SleeperZ]

Yup, you got the wrong diff. The 280ZXTs have an R200, but it has CV shafts and a 3.54 ratio, not the 3.90 you want. The shafts are no problem, you can get flanges from another R200, but that won't solve your ratio problem.

 

[greydog]

Phil-I think SleeperZ's right. You can use the cv flanges from your diff in the R200 you bought but if its really from an '81-'83 ZXT, the ratio is 3:54. You can tell for certain by counting the pinion teeth and ring gear teeth and doing some simple division. The na-5 speed's had 3:90's so you have a good chance of having a usable diff, you'll just have to find out the ratio.
Dan

 

[phil280zxt]

I have a feeling that the donor car was not a turbo, it was totally parted out when I saw it so there was no way to tell. I've asked the seller for the VIN but he has not replied yet.

I have already opened the case on the "new" diff and verified that is a 3.9 ratio, but I am still confused. How can I use my CV half shafts with the "new" 3.9 R200 that has the non-CV flange? Can the flanges be added to my CV halfshafts or can the flanged R200 accept the CV halfshaft? with modifications??

Thanks again,
Phil

 

[avery kepple]

hello, i'm not sure of your problem, but i to am looking for r1200 info also. i have a 74 260 and want to replace the r180 with the r1200. If you get any helpful info can you relay. If not thats ok thanks anyway.





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[Nitrouz boy]

I could be wrong, but im pretty sure you dont have an r200 I believe they were cv shafts on the 200's. at least the ones off the turbo models. But i would definately not downgrade from the cv's they are part of the strength of an r200....NB

 

[Vinhzxt]

Phil,
The 82 280ZXT has the same rear end as your car. The 3.9 R200 came with the non turbo cars GL models and they use the same half shafts as yours. Just yank the ones off the one you 've bought out and slide your half shafts in there (if the one you bought is actually a 3.9 R200). The 3.9 R200 should fit right in with your car. good luck
Vinh

 

[alan240zt]

Re: R200 Diff Answer

The question I believe you have is how to "yank" the C.V. joints from the differential. Use a tire iron or crowbar and pry between the case and C.V joint. The stub axle shaft will suddenly pop out. They are held in with a "C" ring inside the differential. The C.V joint and universal joint types are interchangeable between differentials (as long as they are both R200's). Good luck.

 

[phil280zxt]

Re: R200 Diff Answer

Great, I'll have to give that a try tonight!!

Hope everyone realizes how great a resource this forum is!! I getting a lot more enjoyment out of owning this Z than my first Z 20 years ago because I feel I can do just about anything on the car myself as long as the forum by my side!!

Thanks again,
Phil