RB26powered74zcar Posted October 17, 2002 Share Posted October 17, 2002 I have a R200 3:7 LSD in my 260t right now with a 83zx5spd and I'm thinking on going to the 200R GN auto. Will it be a better set up to use my R200 3:54 LSD with the 200R than the 3:70, gearing wise? I don't know anything about the auto gearing. I drive this car everyday and I would like good street gearing / freeway. BTW, any good diff guys out there that would do me right on a refresh, (clutches, bearings, setup) on the 3:54 LSD. Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted October 18, 2002 Share Posted October 18, 2002 What kind of mileage are you getting with the 5 speed? No need to get excited about the 3.54 until the results are in on the LSD. I just mounted a 2004R and found the floor board rather rumpled where the transmission cross member bolted up.The 2004R mount is way back there at the very end of the tranny.I made my own tranny cross member to basic JTR specs without the exhaust allowance since the car will have side pipes. I used about 4 inches left overs from the 3/8 bar stock material to make the cross member on the inside on each side as a giant washer to crush the floor board rumples and flatten them out. I caught all the flat surface of the tranny mount to meet with the cross member giving me enough of the flat part of the floorboard to take a set to even out the rumples by tightening the mounting bolts. If I had centered the tranny mount on the cross member there would not be much of any flat space to take advantage of to accurately crush the floor board to a level in keeping with the drive shaft angle phasing. Plenty of room in that tunnel with the old cross member removed Quote Link to comment Share on other sites More sharing options...
RB26powered74zcar Posted October 18, 2002 Author Share Posted October 18, 2002 sorry,that last post went right over my head and I'm pretty tall too.... Quote Link to comment Share on other sites More sharing options...
240Z Turbo Posted October 19, 2002 Share Posted October 19, 2002 Joel, the 2004R has a .68 overdrive so you will want to use the 3.7 and not go lower. Quote Link to comment Share on other sites More sharing options...
RB26powered74zcar Posted October 20, 2002 Author Share Posted October 20, 2002 Thanks James, that's what I was after...... Quote Link to comment Share on other sites More sharing options...
jeffp Posted October 20, 2002 Share Posted October 20, 2002 Good answer James, I was going to ask what the over drive gear was. The T5 is .780 and it was setup stock with the 3.54 gear. That was a good combo with 15 wheels. It put the RPM's at about 3100-3200 @ 85 or so. The Nissan tranny would have lowered that figure. I am running the 3.71(tecinally by the gear set numbers) with my T5 and it has worked out well. Quote Link to comment Share on other sites More sharing options...
Scottie-GNZ Posted October 20, 2002 Share Posted October 20, 2002 With the 200R4, do not worry about around town or highway driving. Focus on the max RPMs through the traps in 3rd gear at the MPH you expect the car to run. Trust ME, you do not want to shift to OD on the top-end in the 1/4-mile. A lock-up torque converter is a must. Lets say your MPH target is 125, then the typical tall DR(say 25.8") will have you at about 6,180 with the torque converter locked up. The 3.54 would be about 5900+. If you run a shorter tire, say 24.8", then the 3.70 would be about 6430 and the 3.54 would be about 6155. Just remember that a lower ratio or shorter tire will require more RPMs thru the traps and vice-versa. The reason why I said not to worry about street/highway is because, in normal driving, the 200R4 acts like a 5-speed with 1,2,3,4 and in my case a computer-controlled converter lock up at 45mph. The lockup is like another gear shift so it does not really matter what ratio you are running on the street. Quote Link to comment Share on other sites More sharing options...
RB26powered74zcar Posted October 21, 2002 Author Share Posted October 21, 2002 Thanks fella's. Nice food for thought... Sounds like I don't have too big of a delima. I just wish I could get the most important question, to me, answered, the rebuild/refresh. I hate to think of sending this thing off to someone, rubbing his hands together, with a big smile, saying to himself, now that I have this thing here, in my shop, I can stiff him with no vasaline.. I guess what I'm after here is a refernce from someone who knows someone.. please...... Quote Link to comment Share on other sites More sharing options...
pparaska Posted October 21, 2002 Share Posted October 21, 2002 I'm no master mechanic and I thought dis-assembling and assembling the LSD was dirt simple. I have some rebuild documents from Nissan in PDF (thanks Ross!) that can guid you through it. The parts (clutch parts) are not cheap though. The nice thing is that you don't have to mess with the pinion depth or gear lash - just put the shims back where they came from when you pulled the LSD out of the case. Quote Link to comment Share on other sites More sharing options...
RB26powered74zcar Posted October 22, 2002 Author Share Posted October 22, 2002 Thanks for the input Pete. So I guess if I'm fairly good with my common sense, I could handle this task... Would changing the bearings be something the average wrencher could handle also? I've done all my own work on my Z, so I guess I'll go ahead and give this a shot, it's just that it seems intimidating talking about shimming and gearlash I hope if I run into a problem, you guys will be there to pick me up Quote Link to comment Share on other sites More sharing options...
pparaska Posted October 23, 2002 Share Posted October 23, 2002 J., the bearings press off and on the carrier. I'd think you could take it to a shop to have that done cheap if you don't have a press. You could probably use a gear puller to pull them off yourself and just have the shop press new ones on. Quote Link to comment Share on other sites More sharing options...
RB26powered74zcar Posted October 23, 2002 Author Share Posted October 23, 2002 After I was to change the bearings, would there be anything special or critical to watch out for? I mean is it just that easy, press off/on, put back together and go? Other than changing out the ring and pinion, what parts are changed during whats considered to be a rebuild? This is a R200 LSD with the 10mm ring gear bolts. Thanks again for your help... joel Quote Link to comment Share on other sites More sharing options...
jeffp Posted October 26, 2002 Share Posted October 26, 2002 Hi Joel, you just may want to have someone do the work for you. When you change out the bearings, chances are that the ring and pinion gear back lash is going to change. Also when you do the clutches you will want to shim the clutches about .015 extra to help out the break away torque. You can give David a call at Mlvern racing and discuss this with him. He has allot of experience with the diff. I had Robello set up my diff because I did not want to chance buying the shims. They run about 10.00 each from Nissan, so it can get expensive very quick, and they don't stock the shims. Even the Nissan guys dont fix the diff's they replace them. Robello did a good job for me, and it was a gear set change out for me with a Quaife carrier(diff) They charged me about 200.00 to set it up. so you just may want to think about that in stead of doing it yourself. The problem is changing out the bearings, I am almost positive it will change the backlash on the ring and pinion, and if it is wrong the diff will howl like crazy and drive you crazy. anyway just my o2 here Quote Link to comment Share on other sites More sharing options...
David K Posted October 26, 2002 Share Posted October 26, 2002 jeff i emailed you at mrjeff. Quote Link to comment Share on other sites More sharing options...
pparaska Posted October 26, 2002 Share Posted October 26, 2002 I agree with Jeff, if you take change the bearings, it'll probably hose the placement of the carrier side to side, mess up the back lash, and cause whine. $200 to go through one is not bad. Quote Link to comment Share on other sites More sharing options...
RB26powered74zcar Posted October 26, 2002 Author Share Posted October 26, 2002 Thanks Guys...... I will give Dave a ring Mon. and see what he says about it. The 3:54, really at this point, shows no sighns of any problems, it's just that sinse I have it out and as a spare, I thought I would have it freshend up in case I wanted to use it with a 200R4 swap. thanks again joel Quote Link to comment Share on other sites More sharing options...
Mike C Posted October 26, 2002 Share Posted October 26, 2002 The backlash MAY slightly change, but bearings are machined to such precisicion that worse case it returns the gears to OEM locataion. I would not hesitate to change the bearings and reinstall with the same shim setup it had in it. Actually, I have done this quite a few times with no problems. Not in a Z diff, but in many hypoid rear axle assemblies. If it came from a NA6 powered car, it probably doesn't need an R&R. If it was in a v8 car and someone did unitrack burnouts, powerbrakes, etc. It's problems won't be bearings but excessive clearance in the spider and side gears if not outright failure of them. Nothing is worse for a non LSD diff than one wheel burnouts. Quote Link to comment Share on other sites More sharing options...
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