I've been bamboozled!

"Wrong Wheel Drive (41%)" (rduncan5678)
08/18/2019 at 12:17 • Filed to: None

I’ve just learned a pretty shitty thing about my Miata. So the previous owner purchased an LS trim Miata with a Limited Slip Differential in 2001. As the original owner, he fastidiously kept track of all maintenance and had a shop do every repair. Well part of that maintenance included replacing the differential in 2016, which would have put the mileage on the car just north of 200,000 at the time.

So this receipt I recalled questioning before purchasing the car. The description of “used diff” is relatively nondescript and I wondered if an open diff could have inadvertently been used. The price seemed kind of cheap for a torsen but $650 isnt totally out of reason for junk yard/salvage parts. So I figured maybe it had high mileage on it and the shop sourced it on the cheap. Fast forward from my purchase in April of 2019 to now in August and I had to have the diff serviced to solve a leaking differential case. I didn’t want to do it myself since it was leaking bad enough that I wouldn’t be able to make it to where I work on the car without running out of fluid.

Well the shop took the diff out of the car to reseal it. I was more concerned at the time that the previous owner had used a 4.1 diff instead of a 4.3 (mazdaspeed diff that nobody likes and is slower) since that would be also useless to me. But to my surprise the shop let’s me know I have an open differential! What that means is that I paid a solid $1k too much for the car since LSD is the number one selling point on these cars.

Now I’m just pissed because I’m not going to be able to sell the LSD from my other car and I have to redo the work the shop did anyways to swap it in. I just hate feeling ripped off though since everything else has gone so well with this car relatively. I have a few issues to solve but all of them are track reliability of a 250k mile car.

DISCUSSION (32)

gettingoldercarguy > Wrong Wheel Drive (41%)
08/18/2019 at 12:39

Time for a giken

Rusty Vandura - www.tinyurl.com/keepoppo > Wrong Wheel Drive (41%)
08/18/2019 at 12:53

The original owner probably was clueless about it. The shop may have been clueless as well. No less of a suck for you, though.

Could a gear shop rebuild this one for you and bring it up to the other standard?

Rusty Vandura - www.tinyurl.com/keepoppo > Rusty Vandura - www.tinyurl.com/keepoppo
08/18/2019 at 12:54

Could a gear shop rebuild this diff and bring it up to the other standard?

Dr. Zoidberg - RIP Oppo > Wrong Wheel Drive (41%)
08/18/2019 at 13:02

Why was the diff replaced anyway?

For Sweden > Wrong Wheel Drive (41%)
08/18/2019 at 13:20

I'm not suggesting you burn down the seller's house

Wrong Wheel Drive (41%) > Rusty Vandura - www.tinyurl.com/keepoppo
08/18/2019 at 13:25

No, the lsd is a completely different diff from the open diff. It’s the same on the outside but inside it’s not interchangeable. I have an LSD still installed on the other car though so I'll just pull it off and bolt it on this car.

Wrong Wheel Drive (41%) > Dr. Zoidberg - RIP Oppo
08/18/2019 at 13:26

No idea, I assume it broke somehow. Probably leaked and then driven with no fluid or something dumb. I imagine with 230k things break. I didn't really question why because of that.

Dr. Zoidberg - RIP Oppo > Wrong Wheel Drive (41%)
08/18/2019 at 13:29

Really a shame. How much do you supposed you'd have to pay to swap in the correct used diff with LSD?

Wrong Wheel Drive (41%) > gettingoldercarguy
08/18/2019 at 13:29

I've got a torsen spare laying around so it should be fine to just use that. The shop I go to was telling me he worked on one Miata where they installed a Kia diff or something weird in order to get a 3.4 ratio. But I'm not looking to do anything beyond a normal torsen part.

Wrong Wheel Drive (41%) > For Sweden
08/18/2019 at 13:36

I honestly believe he was just oblivious to it based on the rest of my discussions with him. There's also no way to know without taking it apart and confirming the gears. It's possible the shop didn't even know or check either.

diplodicus forgot his password > Wrong Wheel Drive (41%)
08/18/2019 at 13:37

4.3 would be quicker than a 4.1 unless you're talking about top speed

For Sweden > Wrong Wheel Drive (41%)
08/18/2019 at 13:38

That’s why I’m not suggesting it

DipodomysDeserti > Wrong Wheel Drive (41%)
08/18/2019 at 13:54

This is why I always rip a gnarly burnout when test driving used cars.

XJDano > Wrong Wheel Drive (41%)
08/18/2019 at 13:56

I’ve heard them called carriers. As the side bearing are carrier bearing because they carry the gears and such.

I also snatched up this open carrier with ring gear and “lunchbox locker” out of the scrap bin at my buddies shop.

The locker replaces the spider gears, so that when power is driven from the driveshaft, the locker engages, but the teeth and springs allow the coasting around a corner and clicking of the gears.

Is a cheap solution for off roaders to lock the axle instead of changing the carrier out.

Also a mini spool does same thing, but a solid chunk where it’s locked all the time

Is guess they don’t make these for Miatas?

Kinja'd!!!

Wrong Wheel Drive (41%) > Dr. Zoidberg - RIP Oppo
08/18/2019 at 14:54

Well it would be like $500 in labor but I’m gonna do it myself. And the used diff would be like $ 7-800. But I have the diff as well so it's free. Just lost cost of selling it.

Wrong Wheel Drive (41%) > diplodicus forgot his password
08/18/2019 at 15:06

Well you run out of gear faster, which generally results in slower lap times from what I understand. So 0-10 is probably faster but due to constant shifting, time is lost that way when going faster.

Wrong Wheel Drive (41%) > XJDano
08/18/2019 at 15:09

I've never heard of it but I'll look into it and see if it's been done!

Wrong Wheel Drive (41%) > DipodomysDeserti
08/18/2019 at 15:09

That's pretty much the only solution lol.

diplodicus forgot his password > Wrong Wheel Drive (41%)
08/18/2019 at 15:14

Every gear is 4.7% faster/shorter. I think you'd really only lose time if you're hitting the Rev limiter in top gear on the straights.

XJDano > Wrong Wheel Drive (41%)
08/18/2019 at 15:27

It may be more of a off-road thing, but I figured I’d introduce you to more mechanical automotive stuff. From what I remember they had some sort of spool for the VW golf transmission race stuff

Kinja'd!!!

Cash Rewards > Wrong Wheel Drive (41%)
08/18/2019 at 16:28

You think he got screwed by the shop? Or honest mistake?

MKULTRA1982(ConCrustyBrick) > DipodomysDeserti
08/18/2019 at 16:29

I always do this even if I’m not looking for an LSD (I wish I shopped for things that had them), one to gauge how broken things are, second to gauge the owner’s reaction. If they’re totally cool with it I know the car was likely abused (which can be good or bad, but is worth knowing)

MKULTRA1982(ConCrustyBrick) > Wrong Wheel Drive (41%)
08/18/2019 at 16:31

I have never driven an LSD equipped car but doesn’t it feel substantially different when you lose traction? Or is there some kind of traction control kicking in too? Even if the PO wasn’t savvy I would think they would have noticed the change, but it sounds like you’re certain they deserve the benefit of the doubt.

Wrong Wheel Drive (41%) > Cash Rewards
08/18/2019 at 19:58

I have no way to know. It doesn’t really matter from my perspective though. It’s just a shit sandwich to be dealt. But lesson in here is to follow a hunch. I suspected that this was a possibility when I saw that receipt. I knew it would require a mistake or dishonesty but mistakes happen and such is life. I could have found a part number or contacted the shop or something like that. There was enough evidence to warrant research. And it could have been a worse problem like a bad engine or hidden rust.

Idk, I don't see the value in trying to source the blame. I just have to deal with the problem and just accept the money loss.

Wrong Wheel Drive (41%) > MKULTRA1982(ConCrustyBrick)
08/18/2019 at 20:01

I mean I didn't even notice and I'm tracking the car. He definitely was just driving it around as a Sunday cruiser for the most part. He only put 10k on the car in three years with that diff. Sure he drove it 230k in 15 years before that but you have to be on track to notice. I'm just oblivious I guess but I did notice I was slower and couldn't quite place it. And with the tires I use, I'm not hitting traction limit too often.

Cash Rewards > Wrong Wheel Drive (41%)
08/18/2019 at 21:11

That's a good outlook to have. Good luck!

Snuze: Needs another Swede > Wrong Wheel Drive (41%)
08/18/2019 at 22:05

For future reference, you could have checked both prior to purchase. To check the drive ratio, jack the car up, and out a piece of tape on the driveshaft and one on the wheel. Put the car in neutral then rotate the driveshaft by hand several revolutions (5-10 times) and see how many the tire rotates. Then divide drive shaft rotations by tire rotations.

Also, with the back up, rotate one tire by hand. If the opposite tire spins in reverse, its open diff. If it spins forward, lsd. Another way is jack only one side of the rear up and try to turn the wheel. If it spins, open diff, if it doesn’t or is extremely hard, lsd.

R egardless, Im sorry you got screwed on this. But you seem to have a plan and a good attitude about it. Best of luck!

Wrong Wheel Drive (41%) > Snuze: Needs another Swede
08/18/2019 at 23:26

Ahh that second paragraph makes sense! I observed that when I had the car jacked up for something else recently and saw the opposite spin. I thought it looked odd but hadn’t connected the dots . That would be an easy check too.

HammerheadFistpunch > Wrong Wheel Drive (41%)
08/23/2019 at 16:29

That stinks. on the plus side you are going to have a whole different car when the torsen goes in. So thats nice!

HammerheadFistpunch > diplodicus forgot his password
08/23/2019 at 16:30

You’d have to shift gears more often though since you would be hitting the redline earlier for speed.

Wrong Wheel Drive (41%) > HammerheadFistpunch
08/23/2019 at 16:39

Seeing as I just paid too much money to have this diff fixed, I'm just going to drive it as is for now. I agree, the car will be way better once I put the other diff in. But right now it's problem free so I'll just deal with it. That's not to say the car is problem free anyways so I'll take care of the other issues first. Right now is still a bad time for the track since it's hot anyways. So I hope to have the car at 100% by the time October/November and the cooler weather rolls in. I have plenty of other hobbies to keep my occupied in the mean time.

diplodicus forgot his password > HammerheadFistpunch
08/23/2019 at 20:30

The time it takes to shift will stay equal between rear ends though so we ther your lap times are faster or sower will bdependent on the track. The 4.3 is technically a quicker diff though