SC2 DOHC transaxle year code
 

I have these plans for my 98 SC2. I have swapped out he engine with one that had lower miles on it and have it rolling down the road now. But I have these plans to keep me moving. First off I acquired an MP3 and also an MFactory LSD. The plan is to rebuild the 98 engine mate it with the MP3 I just got with lighter flywheel. The question I have now is I don't know what year of the car the MP3 came out of. There are numbers and letters stamp all over the thing that should let me know that info if I knew what I was looking at. I have looked online but found confusingly different information. I will post some pics here that I took. I am leaning toward a 1992 version. this would be nice as the ratio on 2nd gear is a tad lower so in my my mind a little more grunt!
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The date code is indicated by the number in front of the "MP3" in the stamped number that includes MP3. I believe it is somewhere near where the ects is, but on the bell housing.

Hi derf, I looked everywhere looking for the "MP3" and didn't see that. I guess tomorrow I will go out and see if I can man handle it to get some different views ...would that number be a single digit?

Yes, if 4MP3##,#...

Then 1994

I suppose that changed when they got the 2001, that was probably 11...?

Hey derf, went out to the shop this AM and flipped the tranny over and found the MP3 number. I was really thinking it may be a newer one by the painted writing on the case (01/01) by the people who sold it to me. I was also curious about the clutch damper bracket as it was different from my 98 SC2 (all findings in photos) But , it turns out to be a 92 evidently. which is really what I wanted for that 2nd gear. It probably doesn't make much difference but being a product of the 60s we liked lower, close ratios numbers LOL
Years 1 2 3 4 5 R Final Gear 1998-2002 3.250 1.950 1.423 1.033 0.730 2.923 4.063
1991-1997 3.250 2.056 1.423 1.033 0.730 2.923 4.063
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10/01 is consistent with when they probably received the transmission.

Be advised that 91 and 92 were the design correction years for the S car in many ways and areas. They were still debugging the original design so 92 parts were sometimes radically different then 91 parts. That all seemed to stabilize in 93. So you may in fact find differences between the 92 and later versions of the MP3 in the S cars.

I'm not a transmission guy so I can't tell you what to look for as far as differences that matter.

Yeah derf that makes sense 10/01 being the date they got the tranny but wow they hung on to it a long time ...I got it off of Ebay. I have seen a lot MP2s and their counterpart automatics but this is the first MP3 I have seen for a long while for sale. Looking over the 92 tranny the case is identical to my 98 the only differences externally that I see is the bracket for the slave damper. The bolts holes on the case are the same so the later style bracket will bolt on. I even took my old 98 clutch slave and found it fits in the opening as it should. The next step is to get the MFactory lsd installed. I am still debating on whether to do that myself or have a tranny specialist do it. I have the tools and have tore down and repaired a lot of older manual transmissions but have not done a transaxle especially a Saturns'. I'm hesitant because of that. I could probably do it but it would be a first and the first time you do something like this with no one around to add some guildense usually doesn't turn out like it should.

I'm going to venture that you don't see a whole lot of MP3s because a much higher percentage than the automatics are still on the road or have had the diff pin launched through the case. As for vs MP2s, couldn't tell you. The rebuild/resale market for MP3s must be so small that yards don't bother pulling them because they'll sit on the shelf for 9 years like yours.

I actually got a 9 year old tranny that this old duffer feels a 9yr old tranny is almost new! But, if they got that box in 2001 my math says it sat on the shelf for almost 24 year! I think I will try and contact the seller as that seems like an awfully long shelf life unless they completely forgot it.

No clue how I came up w 9 years