The TRUTH about putting J30 VLSD "guts" in your S13 pumpkin

[AaronMC]

I posted this on NICOClub, but I thought I would share this on here for those who don't forum jump.

I searched all over the interwebs when planning my VLSD swap, and not once did I find anything that warned about what was to come. Here is the story (and some pictures later on).

After welding my open differential, and finding out that a new pair of tires is down to the nylon in 30 days of daily driving, I decided it was time to move to an LSD.
Doing all of my research, I was a little wary of the 3/4" length difference between the J30 pumpkin and S13 pumpkin (not realizing the driveshaft has that much play in the tranny anyway....) So I thought I would just put the VLSD inside my S13 pumpkin. I searched and searched for every post I could find on the subject, and from what I read, everyone said it should work, it would work, blah blah, you just need the input shafts and all that good stuff.

I went to my local Pick 'N' Pull where J30s are abundant, and pulled myself a VLSD. I went and ordered some new thrust washers from Nissan, since I heard the left shim was usually thicker than the right, and that the wearing of the thrust washers is how the VLSD loses its potency. I was also a little excited about the lower gear ratio, as I deliver pizza for Amici's, and increased gas mileage means more $$ for me :snoop:

I apologize for the lack of pictures for the first half of this explanation.. in all of my frustration, making a post about this never came to mind.
So I attempted to install the VLSD, making sure I kept the carrier spacers from my differential in order of how they were when I took it apart, and it would not go in, I tried turning it, I tried turning the pinion gear, it just wouldn't go in. Taking a second look, I realized the 47 tooth J30 ring gear is about 1/2" thicker than the 49 tooth S13 gear. So I swapped the carrier spacers to the other side to shift the ring gear over a little bit. It went in! It had a little bit of play, about a millimeter or so of movement, but I thought that was okay, so I installed it and took it for a drive. I immediately knew something was wrong. When changing from stop or coast to moving force, and vice versa, there was a knock, and while coasting, it sang like no other, filling the entire car with it's painful harmony.

I decided to swap the 49 tooth S13 ring gear onto the VLSD. It worked, but not so cherry. I will explain down below, but first, I must let you know, the first thrust washers I installed were the 1.49mm ones. Just a fair warning to you guys, Idk what everyone else is talking about, saying doubling up on thrust washers makes it "stiffer, like a 2-way diff." I put two 1.49mm washers in there and it was literally as stiff as the welded I had in there beforehand. :facepalm:
I'm not going to mention any names.... *cough cough* http://zilvia.net/f/s-chassis/200226-shimming-r200-j30-vlsd.html *cough*
So I installed two 1.01mm washers and it drives oh so smooth.
I decided to start taking pictures for you guys when I took the diff out yet again to swap in the thinner 1.01mm shims.

So it fits with the spacers in the OEM positions. That little black ring is the rubber ring that protrudes from the opening for the input shaft to protect the inside of the differential from debris and other goodies.
http://i1049.photobucket.com/albums/s383/AaronMC_/S13/2012-12-10_09-51-42_929_zpsaa732aa1.jpg

I will explain why the ring was torn off as the pictures continue
http://i1049.photobucket.com/albums/s383/AaronMC_/S13/2012-12-10_09-51-58_705_zps12b4f25f.jpg

4.08 gear ratio VLSD :dblthumb:
http://i1049.photobucket.com/albums/s383/AaronMC_/S13/2012-12-10_09-52-39_408_zps28c65f08.jpg

...Does this look a little off to you? The VLSD was built to center the input shafts with different shaft lengths. That center was obviously designed to be in the center of the J30 VLSD, which has a thicker ring gear. The consequence of shifting the VLSD over to compensate for the thinner ring gear is shown below.
http://i1049.photobucket.com/albums/s383/AaronMC_/S13/2012-12-10_09-56-01_565_zps86e8c634.jpg

Thus the cause of the torn off rubber dust ring. Thankfully, there won't be any dust making it's way in there.....
http://i1049.photobucket.com/albums/s383/AaronMC_/S13/2012-12-09_14-50-49_426_zps9592dc16.jpg

And the other side protrudes, as you can see
http://i1049.photobucket.com/albums/s383/AaronMC_/S13/2012-12-09_14-51-01_228_zps63429f22.jpg

To install the differential with this setup, you need two people. I used to be able to do this by myself, but unless you can bench press multiple reps of 250, I suggest you don't attempt to do this on your own. First, you have to disconnect the exhaust hanger by the gas tank, and disconnect the sway bar brackets. Have you partner lay on the driver side, and you on the passenger side, and as you lift the differential, you put the nose in above the sway bar first, next, lift the back end of the diff above where it sits when aligned, then tilt the differential, lowering the passenger side input shaft , holding with one hand while your partner attempts to hold the tilt, take your other hand and shove the axle end into the input shaft. After that you can install it as you normally would. The passenger side axle, however, cannot be installed any other way.
http://i1049.photobucket.com/albums/s383/AaronMC_/S13/2012-12-09_14-51-21_732_zps65c35a49.jpg

The only downside to doing all of this is a little whir from the driver side CV axle while coasting (due to the excess play I would assume.)
If you decide to try some 1.49mm thrust washers against my advice, be warned, for this will happen to your driver side CV joint..
(Yes, that's an imprint of an axle bearing on the cap.)
http://i1049.photobucket.com/albums/s383/AaronMC_/S13/2012-12-09_15-18-24_247_zpsfbe8aba9.jpg

So there you have it. Since none of this information came up in all of my pre-project research, I assume nobody has ever tried this before, or if they have, they never cared enough to share with everyone else the trouble they will go through getting this done.

[jr_ss]

So did you swap pinion gears? You do realize a ring and pinion set is a mated pair from the factory? You cannot swap a lower ratio ring gear on to a pinion that came from a higher ratio. Most of your noise issues came from your cross breed of the ring and pinion mismatch.

[Tearlessj]

You CAN mix match, but you need to properly shim the gears. It gets pretty complicated so I won't get into it. 4x4 people do it all the time.

[KendallH]

This seems incredibly sketchy just to put a shit VLSD into your car. Decent writeup though...?

[inopsey]

You CAN mix match, but you need to properly shim the gears. It gets pretty complicated so I won't get into it. 4x4 people do it all the time.

the differential in these cars use hypoid gear sets. you cannot mis and match a hypoid gear set. nissan doesent even sell the pinion separate for a reason, you can only buy a gear set for the differential from nissan. .

[jr_ss]

You CAN mix match, but you need to properly shim the gears. It gets pretty complicated so I won't get into it. 4x4 people do it all the time.

That doesn't make it right. Ring and pinions are mated pairs, cast and machines together at the factory. They should never be mismatched. That's why they are sold together when purchasing new.

[Duke89]

That doesn't make it right. Ring and pinions are mated pairs, cast and machines together at the factory. They should never be mismatched. That's why they are sold together when purchasing new.

They are only sold together so Nissan can make more money. Nissan has no reason to sell them separate. You can mix and match.

[jr_ss]

They are only sold together so Nissan can make more money. Nissan has no reason to sell them separate. You can mix and match.

I wasn't saying Nissan specifically. Any R&P, from any manufacturer, are sold as pairs. No, you cannot mismatch.

[AaronMC]

This seems incredibly sketchy just to put a shit VLSD into your car. Decent writeup though...?

I've driven over 10k miles on this setup, without a single issue whatsoever, and I drive it pretty hard. Both CV axles are fine, no clunking, no singing, no whining. And the VLSD with its new, slightly thicker thrust washers works wonderfully, actually.

[AaronMC]

So did you swap pinion gears? You do realize a ring and pinion set is a mated pair from the factory? You cannot swap a lower ratio ring gear on to a pinion that came from a higher ratio. Most of your noise issues came from your cross breed of the ring and pinion mismatch.

jr_ss is right. The pairs are mated, and once used, they stretch together ever so slightly, destroying any chance of interchangeability.

I had never done any diff work before this, but I learned that when I put the 47-toother in there. That's why I put the original ring gear back on, the one that has been with my pinion for the past 180k miles.
I used some gear paint on two sets of 5 teeth on my ring gear when installed with the VLSD and checked the wear patterns, making sure the smudges weren't too close to the face, heel, or toe, or too short or long.

[240SilviaX]

lol done the install on my own ,, use a jack ,, I used the shimmed J30 vlsd with 240 open ring in the s13 case.. the J30 ratio is 47-12 tooth 240sx is 49-12 both having 12 tooth pinon gears as long as you mesh the gears correctly using the bearing race spacers and the correct shim like i have done. Ive used the yellow mesh paint as well.. Ive also cut the axle shaft down in a lathe to fit in the case like stock.. both sides fit like stock.. Ive driven this car for 6 months putting 700 miles a week and canyon runs and not had a problem.. so it can be done.. if your mechanically inclined enough.. there is a pic of the axle shaft in the other J30 R200 post .. otherwise go back to the J30 ring get better milage and get that axle shaft back in the case cuz looks like your going to leak gear oil everywhere ..

[foreverdeath]

very nice write up wish this was up when i put a picknpull j30 in my s13 back in november. worked like a charm minus the input shaft sticking a tad but thats because the snap ring gets stuck in the diff and makes it imposalbe to fully install again unless removed. you can not mix match ring and pinions even ford wont sell you just a ring for this reason. when you shim a VLSD you open up the VLSD its self and shim the a spider/side gear. i weight 125 and i easly did all on my own over an afternoon, 3300mi and no issues yet. hardest part was benching/jacking it while trying to insert the retarted cones on the axles into the output shafts.

[240SilviaX]

there are 2 different sets of shims in this unit. the shims that we add for tightness of the vlsd unit, and the rings (shims that space the vlsd for proper gear mesh) behind the bearing race underneath the main caps.
http://i1320.photobucket.com/albums/u530/Eric_Typner/Axleshaft_zpsc1b1b62f.jpg

[240SilviaX]

You guys don't have problems of leaking oil from the axle shaft that sticks out?

[foreverdeath]

not at all

[laurentj23]

Sorry to bring this thing up. So do I need to swap the j30 pinion and well to fit into the r200 housing?
So basically I pull apart the j30 ring gear and diff. Take the r200 ring gear and diff and replaced it with the j30 ones right? Should I use the j30 output shafts or r200? I just want a longer gear ratio. And it's easier to just swap the j30 and bolt it in the there but it requires me to change my driveshaft $300.