Hello everyone,

TLDR: Will a 4T60-E from a 1995 Oldsmobile Eighty Eight function properly in a 1996 Oldsmobile Eighty Eight (same RPO codes (M13/F17), both are 2.84 FDR)? And is it correct that I should remove the wiring harness from the replacement transmission (the 1995) and use the wiring harness from my original transmission (the 1996 Oldsmobile Eighty Eight’* transmission wiring harness)?

So far I have a new OEM radiator, a new OEM radiator cap, new OEM coolant hoses, twenty gallons of distilled water, three gallons of Havoline Dex-Cool coolant, new OEM thermostat, new OEM transmission cooler lines, new OEM axle seals, sixteen quarts of AMSOIL ATF, and the used 1995 replacement transmission itself.

My question is in regards to the interchangeability of a 1995 4T60-E to a 1996 4T60-E. It seems that it will work, as long as I remove the “trans harness” from the 1995 4T60-E and put the “trans harness” from my broken 1996 4T60-E transmission in place of it. However, I’ve found conflicting info and I could use your advice - I just want to double-check to make sure that I’m not making a mistake.

I have found many examples of people using the 1996-1998 4T60-E’* in older (1993-1995) vehicles, but I can’t find anyone who used an OBD 1.5 (?1994?-1995) 4T60-E in an OBD II vehicle. I’m really hoping it will work, as I really have no other option at this point.

I purchased the 1995 4T60-E because it was the only one that I could find with under 180,000 miles anywhere. This one has only 83,257 miles on it, but it’* from a 1995 Oldsmobile Eighty Eight. My car is a 1996 Oldsmobile Eighty Eight. Same exact FDR (2.84) and RPO codes – M13/F17. I understand there may be a slight 2-3MPH difference in my speedometer after the swap, which is perfectly fine with me. I just want to make sure that everything else will function as intended, and that my logic is correct in removing the “trans harness” from the replacement 1995 4T60-E and using the “trans harness” from my original 1996 4T60-E transmission. The salvage yard’* software did not show this as a compatible interchange, and that’* why I’m worried - but from everything I read online, it seems it will work fine. I know the interchangeability lists on the junkyard’* software can be a bit overly specific at times. I really appreciate any help possible.

Thank you,


\/\/\/ People who said yes (similar scenarios with 4T60-E'*) \/\/\/
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https://www.gmforum.com/buick-172/4t...d-help-297210/

Post #7

"FWIW, I have successfully put a 97 4T60 into a 93 LeSabre. The only things that had to be done was swapping the wiring harness. The 93 needed the 93 harness."
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https://www.a-body.net/forums/archiv...hp/t-3595.html
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94 88 transmission swap OBDII OBDI - Car Forums and Automotive Chat
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https://www.beretta.net/forum/viewtopic.php?t=24413

Post #3

“94-96 4t60e'* are interchangeable... Only difference is a small change in ratio that does not affect the ECU or shifting.”
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1995 SSEI Transmission : 1992-1999

Post #10

“A 1996 Trans should work fine for him.. the 1994-95 PCM is not smart enough to notice a difference...”
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\/\/\/ People who said no \/\/\/
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'96 Century general project thread - 60DegreeV6.com

Post #1
“One thing people don't tell you about the '96 cars is that lots and lots of parts are one-year-only on them, including the transmission.”
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https://www.gmforum.com/1992-1999-91...eville-220622/
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Post #2
Can I use a 96' 4t60e in place of a '95 4t60e PLEASE HELP : 1992-1999
“No, 95 is a one year only transmission unfortunately.”
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Some of these links are to cars that aren’t powered by the 3800 engine, but they still mention interchangeability of 1995-1996 4T60-E’* in the threads, so I included them for reference.
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I'd give it a 70% chance of working. I know the big transition started in 1997 model year. Others might know more. Yours both being Olds Eighty-Eights increased my 70% from 60% . If one of them was a Pontiac, I'd say 20%.

Thanks for your reply! That makes sense, I think that'* when they began utilizing the 4T65-E.

Does it seem correct to use my transmission wiring harness from my original transmission in place of the transmission wiring harness from the used/replacement transmission?

Thanks again, CathedralCub!

You're talking about the wiring from external plug inwards towards solenoids etc., right?

If so, I'd look for differences first before swapping all of that out. We're discussing moving wires around that have survived being bathed in chemicals for over twenty years. Moving them around could introduce new variables, so it you can avoid, I would suggest it.

A thought: Go check out the various Pontiac Fiero forums out there. Some are better than others. When I run into this interchange stuff, I often find answers with those guys. They seem to interchange all kinds of engines onto all kinds of transaxles.

Yes, I believe so. I think it’* completely external. It just seemed like everyone who swapped theirs, used the wiring harness from their original transmission in place of the one on the replacement transmission. But that is good advice and definitely makes sense in regards to the age and new variables.

Will do. You're right, I've read a lot of posts on the Fiero forums while researching into this, and they seem really knowledgeable when it comes to this kind of stuff.

Thank you!

Also, I posted this same question over on the PontiacBonnevilleClub Forum, and a fellow there (MattStrike) said that it would require swapping the temp sensor. This is the first that I've heard of this, I thought it was the same trans fluid temp sensor for 1995 and 1996. Here'* the thread link: Can I use a 1995 4T60-E in place of a 1996 4T60-E? : 1992-1999

Not my area of expertise, but I was needing to replace my tranny and did some research. Seems to my recollection was that there can be differences in torque converters and/or lockup thrust from year to year. I don't remember exactly, but if you Google "torque lock up difference by year model" or some such, you might find the same discussion I did back when I was doing my research. Apparently, each torque converter has codes on it that tranny shops use to order replacements. I would make sure you have the same converter in each model year. This may be of help: http://www.tcsproducts.com/media/1/Converter_Cat1.pdf

Reading the thread it appears they know more about it than I do. That having been said, I don't know anyone'* reputation over there, but what I saw looked like good information. It might be a good idea to look up the temperature sensor part for each transaxle and see if they are the same part number.