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MT-82 tooth counts and weight?

SolarYellow510

TMO Beginner
5
4
TX
HPDE
20+ Years
I'm planning a build using a Duratec 2.5L in a non-Ford chassis. Trying to decide what transmission to use. The Ecoboost Mustang version of the MT-82 is an obvious option, as it bolts up with the Mustang oil pan. I've found what the gear ratios are for the US Ecoboost and GT versions of the trans, and also found a data sheet that shows an alternate 0.834:1 sixth gear ratio for the European Ecoboost. My build should end up in the neighborhood of Miata weight, so I really don't need the 4.24:1 first gear to get it moving. (It also keeps me from being too worried about durability.)

I'd like to figure out what, if anything, could be accomplished toward creating a really nice, close-ratio box with an even progression of splits by mixing and matching guts from the V-8 and Ecoboost versions of the MT-82. Of course, you can't just put the first and second gears of the V-8 box in the Ecoboost trans and expect to end up with V-8 ratios (which look awesome in the spreadsheet), because the actual gear ratio depends on the gearing between the input shaft and countershaft. What I really need to be able to progress is tooth counts for all the gears. This information is readily available for T-5s, but I haven't found it for the MT-82. I have access to Alldata, which is helpful in seeing how stuff goes together, but has no tooth counts. FordPartsGiant has all the parts, but no tooth counts. Amp Distributing lists tooth counts for a few of the gears, but not enough to solve the problem (edit - see below). Buying both boxes and taking them apart might solve the problem, or it might leave me with a close to a couple grand in disassembled gearboxes that I don't want to or can't use.

Just wondering if anyone here has a box apart, or happened to count the teeth when they had one apart in the past, or knows where this information can be found otherwise.

Also, I've seen published figures for the weight of the MT-82 of approximately 87 lb, 108 lb, and 123 lb. All from sources that should be halfway reliable; the variation proves that clearly they aren't. Has anyone seen a verifiable weight, and know what was included (as in TO brg, shifter, fluid)?

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Additional discussion, just for context and so people don't assume I haven't thought this through:

The other option I'm considering is a T5Z with the input shaft pilot ground to 0.590 and 0.80:1 fifth gear. Which is light and strong enough, but somewhat costly to have built and requires an expensive custom bellhousing. Quick Time at $1100 is currently the only off the shelf option, since Quad 4 Rods shut down. I'm trying to get a UK-based company that makes a bunch of different conversion bellhousings interested, but I don't know when or if that will pan out into product I could buy. There is also an option to build an adaptor plate that mates to an NC Miata automatic trans bellhousing, which happens to bolt to the trans. This is a proven solution (has been used for another transmission), but still an expensive PITA.

Another bolt-on option is the Aisin from an NC Miata, but my plans include enough power to turn those boxes into consumables, plus there isn't a good way to get the shifter in the right location.

Going TKO/TKX would cost even more than the T-5 and still require adaptation. I don't need the strength, and the +30 lb would be significant in this project.

Thanks for any help!

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Edited to add:

So, I went to AMP Distributing and mined what I could, just to see how far it would get me. Didn't expect much, but you have to try. I was able to count teeth on two of the photos where they didn't provide counts in the descriptions. Put what I could find in a spreadsheet, and it turned out better than I thought. I had cluster and main counts for sixth, and the cluster 5th. That let me figure out the input shaft, and with one of the gears for each of the other four, I could try values in the spreadsheet until they matched Ford's published specs. I now have five different values all matching published specs to either three or four significant figures (as many sig figs as were published). Unlikely there is a problem with that level of match. So assuming the AMP stuff is correct, I have the 11-17 5.0 box figured out.

Still nothing on Ecoboost (baby?) teeth.
 
Last edited:

SolarYellow510

TMO Beginner
5
4
TX
HPDE
20+ Years
Well, did more playing in Excel after work tonight. I think I figured it out. Matching the published gear ratios for the EBM version means five separate codes, which are linearly dependent with each other, of four characters each. Or in total, 20 digits that have to match perfectly. I built a tool in Excel to make checking the results faster and did a bunch of guessing to land on the solution that worked. It happens that the first and sixth tooth counts match the V-8 first and sixth pairs, so that further cements my confidence in the answer.

One interesting thing I noticed is that the 1-5 of the V-8 ratios, if you scale them by 0.8, almost exactly matches the ratios of a 2.95-first T-5 built with a 0.80 fifth. Proven solution...

Now, I'm trying to figure out how to acquire the European sixth-gear pair.

Would still love to see someone's MT-82 on a corner scale.
 

mwjscn

TMO Intermediate
43
55
Maryland
I'd suggest sending Ben Calimer a line. He's a well-known MT82 rebuilder and his transmissions are in a few TMO vehicles. He deals with shipping MT82s out day and night so he may have more accurate weight information as well.
 

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