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Discussion Starter · #1 ·
again I know this has probably been covered but I need posts so sorry…….

first off if anyone wants to trade an open diff for a lsd in the northeast us let me know, before I do something stupid.

So heres the thing, I have an 86.5 NA with a lsd, sent it to a shop to have the diff pinion seal re done, and now she isn’t locking up anymore (of course).if I have the lsd rebuilt it will probably cost a lot, and I’m not sure how effective it will be cause I know a welded diff slides great.On the other hand welded diff would destroy the lsd, and probably axles. Anyone have experience with either one drifting around I’m not sure how well the lsd performs/holds up.
 

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I don't think you can weld an LSD, I think you need an open diff for that...
 

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Discussion Starter · #3 ·
Oh, it’s just a clutch type, I thought it has close to the same design as open but with a few extra parts. I was thinking take the spring out and welding a block in its place (or even just weld the spring too)
 

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I've welded LSD differentials before. So it's definitely doable. And in my experience the axles in these cars are decently strong. So you could definitely do it but you would of course have increased tire wear. There is a company that makes upgrade clutch packs for our LSDs that I'm gonna be trying out. Weir Performance. My Supra is a drift car so I'll be going with their pack that basically makes it act like a welded diff. But I haven't used their stuff before so I can't speak to the quality of their kits. Here is the link, look their options. Weir Performance - MAXGRIP LSD Kits

DriftMotion sells rebuild kits for our LSDs also but that's pretty spendy.

Sent from my IN2019 using Tapatalk
 

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Discussion Starter · #5 ·
I've welded LSD differentials before. So it's definitely doable. And in my experience the axles in these cars are decently strong. So you could definitely do it but you would of course have increased tire wear. There is a company that makes upgrade clutch packs for our LSDs that I'm gonna be trying out. Weir Performance. My Supra is a drift car so I'll be going with their pack that basically makes it act like a welded diff. But I haven't used their stuff before so I can't speak to the quality of their kits. Here is the link, look their options. Weir Performance - MAXGRIP LSD Kits

DriftMotion sells rebuild kits for our LSDs also but that's pretty spendy.

Sent from my IN2019 using Tapatalk
I read a little about the maxgrip kits, they look good, a little over my price range right now though, already annoyed I gotta do this again, should have just left the diff leaking cause it WAS working ok.
 

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I read a little about the maxgrip kits, they look good, a little over my price range right now though, already annoyed I gotta do this again, should have just left the diff leaking cause it WAS working ok.
Damn, really? I would take it back to the shop you had do your pinion seal. If it worked before, then they messed up and are responsible to fix it correctly.

Sent from my IN2019 using Tapatalk
 

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The number of diff's I've had to fix after a shop "rebuilt" one is pretty sad to be honest.
Most mechanics have no clue how to rebuild a diff and have no business even opening up one.
 

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What fluid is in there? Too much slip additive will neuter the LSD action. First easy thing to try is change the fluid.
 

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Also how long did it run low on fluid? When I do pinon seals I check the fluid first to look for glitter. If the fluid is questionable I'm sure to let customers know that there could already be damage done.
 

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So, just curious if the OP could provide some useful information. How long have you owned the car? How do you know the LSD was working before?

I ask the latter because the vast majority of LSDs built 35 years ago are no longer providing much slip control. You also used the phrase "lock up" which that unit never did when new and it implies you may not fully understand the device and your expectations are incorrect if so.

Additionally, I have not confirmed this by reading my factory service manual, but I'm confident the shop did not have to even open the differential to replace that seal, based on others I have done. Which would mean the shop is not to blame here. Thoughts?
 

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Weir diff is very nice.
That's what we did with LSD rebuild.
Neat thing about the Weir's, you can adjust the breakaway torque and... no LSD fluid needed.
 

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Discussion Starter · #13 · (Edited)
So, just curious if the OP could provide some useful information. How long have you owned the car? How do you know the LSD was working before?

I ask the latter because the vast majority of LSDs built 35 years ago are no longer providing much slip control. You also used the phrase "lock up" which that unit never did when new and it implies you may not fully understand the device and your expectations are incorrect if so.

Additionally, I have not confirmed this by reading my factory service manual, but I'm confident the shop did not have to even open the differential to replace that seal, based on others I have done. Which would mean the shop is not to blame here. Thoughts?
I know it doesn’t “lock” but it had more locking force before I went messing with it, and for the seal you still need to take the nut off that side of the diff, and that I read on Cygnus needs to be re installed properly. Other threads say it’s easy to take off hard to put back on… to answer other questions, I’ve had the car about a year, I wouldn’t say I babied it but it didn’t see more than 100 miles due to me working on it. But from the time I bought it, up until the repair shop, if I were to dump the clutch it would spin both wheels and stay spinning, while being able to control throttle a bit, where as now It still grabs enough to spin both, but halfway through a corner, anywhere on the throttle I feel one tire start spinning faster and I straighten out. It seems inconsistent, which was me leaning towards it being worn.

edit: this is install procedure for that bearing/seal, I don’t have any knowledge of preload or the tools to measure so I was scared off!
 

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Discussion Starter · #14 ·
What fluid is in there? Too much slip additive will neuter the LSD action. First easy thing to try is change the fluid.
I had the shop use the redline 75-90wNS, and i personally didn’t put any lsd additive in yet (no clue what the shop did or how the fluid looked, figured they would tell me if there was a noticeable issue)
 

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Thanks for posting the procedure. Yeah, that's just a nut off the front of the diff. They don't even have to remove the diff or open it, so as I suspected there was nothing at all done that would impact the LSD action. Now, since they changed the fluid, THAT definitely would change the LSD action. It sounds like you might look into fluid additives that would make it more aggressive. I know you can add friction modifiers available in almost all local auto parts chains, but Im not sure if that merely reduces chatter, or if it can make it more aggressive with more "friction modifier" to get it like it was. Piratip, can probably answer that with half his brain tied behind his back....
 

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I had the shop use the redline 75-90wNS, and i personally didn’t put any lsd additive in yet (no clue what the shop did or how the fluid looked, figured they would tell me if there was a noticeable issue)
If you're running straight Redline 75W90NS and it's not gripping a whole lot, a rebuild is in order. With no slip additive at all, it should be pretty noisy and cause some wheel hop in tight corners.

I suspect the shop put in lots of slip additive because, in general, people don't want any noise and complete smoothness, and they don't want you to come back and complain. It's easy to change the oil yourself as a first step, and then you'd be sure what's in there. That's what I would do.

@IdahoDoug , there's only additive to increase slip - there aren't any that increase the grip. To add grip, you start with an oil, like Redline's 75W90NS, which has no additive and should give too much grip. You then tame it down with additive.

If it does need a rebuild, Piratetip is the guy to do it.
 

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Cool, thanks for the input as I installed an LSD in my Supra when I rebuilt it and will commence playing with it in the spring.

Also, I think the OP was a bit quick on the draw to blame the shop here and this is a sometimes deserved situation, but it's also an oft-repeated disservice to mechanics everywhere. These are 35 year old vehicles that have been through a lot of owners who may or may not have maintained them. Before blaming a shop, please know what you are talking about. Yes, this forum primarily supports members who work on their own, but know there are a lot of knowledgeable and talented people who make their living working on automobiles that tire of the posts claiming "the shop did something wrong" when they did not. Off the soapbox.
 

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Discussion Starter · #18 ·
If you're running straight Redline 75W90NS and it's not gripping a whole lot, a rebuild is in order. With no slip additive at all, it should be pretty noisy and cause some wheel hop in tight corners.

I suspect the shop put in lots of slip additive because, in general, people don't want any noise and complete smoothness, and they don't want you to come back and complain. It's easy to change the oil yourself as a first step, and then you'd be sure what's in there. That's what I would do.

@IdahoDoug , there's only additive to increase slip - there aren't any that increase the grip. To add grip, you start with an oil, like Redline's 75W90NS, which has no additive and should give too much grip. You then tame it down with additive.

If it does need a rebuild, Piratetip is the guy to do it.
Thanks for the recommendation, I’ll try another flush just in case but I feel a rebuild is on the way
 

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Discussion Starter · #19 ·
Cool, thanks for the input as I installed an LSD in my Supra when I rebuilt it and will commence playing with it in the spring.

Also, I think the OP was a bit quick on the draw to blame the shop here and this is a sometimes deserved situation, but it's also an oft-repeated disservice to mechanics everywhere. These are 35 year old vehicles that have been through a lot of owners who may or may not have maintained them. Before blaming a shop, please know what you are talking about. Yes, this forum primarily supports members who work on their own, but know there are a lot of knowledgeable and talented people who make their living working on automobiles that tire of the posts claiming "the shop did something wrong" when they did not. Off the soapbox.
I wasn’t trying to blame the shop just saying what’s going on, I’m not familiar with rebuilding one of those so I don’t know the importance of that bearing preload. Going to have to do some studying!
 
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