S15 Helical into S13VLSD

[Zeph240sx]

Hey guys i got a S15 Helical for cheap anyways before i attempt i wanna make sure that i could fit the S15 Helical Diff into VLSD case with Original VLSD shims.
Or do i need to measure and get different shims? I searched and i find that some people could fit S15 Helical into S14 VLSD with stock shims No problem. But what about S13? Same thing?


It would save me so much time and trouble if i could just use the VLSD shims and call it a day

Thanks

[centralcoaster33]

The shims are the same in diameter. The thicknesses of the shims are application specific, so unless your helical is the exact same as the viscous (odds are only slightly better than winning the lottery), then you'd need the appropriate shim thickness to get your lash/ lap correct.

You have all you need to put something together, but to do it correctly, you might want to consider new bearings and seals, then new shims to set your lap and lash.

I did a lot of mine myself, then outsourced a giant press for the bearings, then couldn't get the thing back in (needed different shims), so ulitmately took it to a 4WD drivetrain shop and had them shim it and set the gear mesh. They mentioned something about stretching the pumpkin to put the diff in and it is like squished in there so hard, I don't know, but it runs great. I like my helical.

[Hijacker]

The S15 HLSD is an R200 diff. Your old VLSD is an R200 diff. They'll fit, but as central said, the shimming will be off. I've rebuilt a few diffs in my time, and it's not HARD, it's just something that you have to be shown. You check lash and lap based on the contact of the ring gear with the pinion gear, and that requires understanding how to use and read Prussian blue imprints. When I was taught, the first words out of my instructor's mouth was "this is like reading tea leaves." He wasn't too far off. I will say that what he considers to be a proper shaped contact patch is different than what the service manual says. But, I haven't had a diff fail or whine yet, and he had about 40 years of experience doing diffs when he taught me.

The only reason I would recommend having a shop shim the diff for you is cost. The shims are not cheap, and there's no real way to say you need X and Y shims without trial and effort. Typically, the numbers I pull up on paper rarely are correct. They get close, but they're always off.

[PapaSmurf2k3]

^Agreed. Even doing valve lash... my math never seems to exactly match the size needed... I can usually swap them around to get pretty darn close though.