(DRIVETRAIN) Miata Diff interchange into 84-85 models

 
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Old 10-09-07, 08:37 PM
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(DRIVETRAIN) Miata Diff interchange into 84-85 models

Just pulled out the 3rd member of my rear on me SE, and it is shot. Both the ring and pinion gears have excessive wear marks and heat damage. I guess I know why it was humming so bad. Anyway, since it is a limited slip, is it worth rebuilding? Should I take a chance on a used one? Or, assuming I have the money, invest in a performance rear?

Mike
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Old 10-09-07, 09:06 PM
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Simplest would be to find a new r&p, then take it to a shop and have them put it back together. I probably have and r&p laying around if you need them. Mine would be the 3.9 gears, not the 4.1 in the SE's.
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Old 10-09-07, 09:08 PM
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I would just rebuild, at least you know it's done right rather than buying used & dont know how long that one will last.
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Old 10-09-07, 09:09 PM
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Originally Posted by trochoid
Simplest would be to find a new r&p, then take it to a shop and have them put it back together. I probably have and r&p laying around if you need them. Mine would be the 3.9 gears, not the 4.1 in the SE's.
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Old 10-09-07, 09:27 PM
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if you have the money, get a kaza for a 1.8 miata and some new gears. if you want shorter gears, get some kia gears
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Old 10-09-07, 09:42 PM
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Trochoid,

Do you mean a 3.933 from an 83-84 12A, or a 3.909, from an 85 12A----just curious :-) Also, what shape are the R&P in? Is there "ANY" visible wear other than normal? I ask this because I thought that my R&P had normal wear until my step-dad told me that it was shot (he's an expert).

Mike
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Old 10-09-07, 09:53 PM
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Originally Posted by aws140
if you have the money, get a kaza for a 1.8 miata and some new gears. if you want shorter gears, get some kia gears
What is the advantage in getting the 3rd member for a 1.8 Miata?
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Old 10-09-07, 10:14 PM
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well, it is a superior LSD unit. even the stock miata torsen LSD is better than our stock LSD. if you want even better, get the kaza designed for that miata.

im not sure if the miata gears will work, ill have to guess and say no, but i could easily be wrong
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Old 10-09-07, 11:01 PM
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oh **** thats some expensive stuff. looks good but i can put a ford 9" in for that.

http://www.kaazonline.com/8309.html


kaaz's website is here.

http://www.kaazonline.com/

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Old 10-09-07, 11:06 PM
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well thats apples and oranges
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Old 10-10-07, 02:13 AM
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Originally Posted by aws140
well, it is a superior LSD unit. even the stock miata torsen LSD is better than our stock LSD. if you want even better, get the kaza designed for that miata.

im not sure if the miata gears will work, ill have to guess and say no, but i could easily be wrong
How about the KAAZ diff that is deisgn for our car? They are available from Mazdatrix.
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Old 10-10-07, 02:19 AM
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Originally Posted by mjm4jc
Trochoid,

Do you mean a 3.933 from an 83-84 12A, or a 3.909, from an 85 12A----just curious :-) Also, what shape are the R&P in? Is there "ANY" visible wear other than normal? I ask this because I thought that my R&P had normal wear until my step-dad told me that it was shot (he's an expert).

Mike
I don't recall which parts car the gears came out of. Could be 83/84 or 85. I'll have to count the teeth and inspect for wear. PM me if seriously interested.
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Old 10-10-07, 07:13 AM
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Originally Posted by justint5387
How about the KAAZ diff that is deisgn for our car? They are available from Mazdatrix.
It appears that the Kaaz diffs at Mazdatrix are for road racing, drifting, etc. They are not for the every day driver. The stock set-up or the torsen is for the everday driver. I may be wrong however.
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Old 10-10-07, 07:14 AM
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Originally Posted by trochoid
I don't recall which parts car the gears came out of. Could be 83/84 or 85. I'll have to count the teeth and inspect for wear. PM me if seriously interested.
I will PM you as soon as I know what I am going to do.

Thanks
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Old 10-10-07, 07:33 AM
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yo put a kia third member on the car
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Old 10-10-07, 07:37 AM
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Originally Posted by aws140
if you have the money, get a kaza for a 1.8 miata and some new gears. if you want shorter gears, get some kia gears
I was thinking about the miata rear. If I were to go to a junk yard and get a miata 3rd member, which year miata should I ask for? Will my stock axle shafts fit into the 3rd member? What is the differential gear ratio on a miata?

Thanks,

Mike
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Old 10-10-07, 08:44 AM
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I've read from some members that the 94-97 Miata 3rd member is a "no hassle" bolt-in replacement for my SE. Is this true? I was also told that not all 94-97 miata rears were limited slip. How do I know which is LS and which is not, assuming the guy at the junkyard doesn't know. Will my SE axle shafts fit into the splines of the Miata?
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Old 10-10-07, 09:46 AM
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How stock is your car?
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Old 10-10-07, 09:50 AM
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I too would like to know since my SE LSD is starting to wear out. Mine is from a 85 SE. What would be the best miata to pull it out of?
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Old 10-10-07, 10:11 AM
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earlier MIATA came with open diffy.
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Old 10-10-07, 11:27 AM
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Originally Posted by Hades12
How stock is your car?
Pretty stock except for racing exhaust and 2Gen DFIS.
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Old 10-10-07, 11:32 AM
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Originally Posted by blown7
I too would like to know since my SE LSD is starting to wear out. Mine is from a 85 SE. What would be the best miata to pull it out of?
You want to take it from a 94-97 Miata, but make sure it is not an open rear. The locked rear (LSD) was an option on certain Miatas. I called two junkyards so far, and they only had to regular rears. They were, however, able to tell me over the phone whether the Miata rears were regular or LSD. If you do the swap, keep in mind that it is a lower gear ratio, I believe 4:30, so your speedometer will be off unless you swap the Miata speedo, if possible.

Mike
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Old 10-10-07, 11:35 AM
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no its not a 4.30. Its only a 4.10.
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Old 10-10-07, 12:14 PM
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94+ miatas. its not that hard to find the units. go to miata forums or craigslist
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Old 10-10-07, 05:08 PM
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Originally Posted by wackyracer
no its not a 4.30. Its only a 4.10.
Great! If it's a 4:10, then it almost identically matches the SE.
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