trans swap 98 S70 to 93 850

Post by **phat78ta** » 16 Apr 2010, 16:33

Anyone know if the trans from a 98 S70 will work in a 93 850? I know the trans will physically fit, since its the same engine and all, but will I have to change the axels or any other of the steering/front suspension gear? I'm assuming I will also need the TCM from the S70. I can get a trans from the local pull a part for cheap, and it would be really nice to have a 5 speed.

Post by **jblackburn** » 16 Apr 2010, 17:12

Is the S70 transmission that you want to get a 5-speed? That would work absolutely no problem, and you'll just remove the TCU entirely from your car. Make sure to get all the hydraulics while you're at it

If it's an auto, the transmission will fit no problem, but the problem will be getting the S70's TCU to talk to the ECU in your 850. From a wiring standpoint, it won't.

Post by **phat78ta** » 16 Apr 2010, 19:37

i thought the auto for the 98 S70 was a 5 speed, LOL. if I get the TCU, will it just throw the CEL(I can live with that) or will it cause more dire problems? If I do a swap, I want to get the best possible trans that will fit in my car. Hate to replace it and have it go bad in a few months to a year.

Post by **wheelsup** » 16 Apr 2010, 21:59

I'm pretty sure the 98-00 model years still have the AW50-42LE.

Post by **jblackburn** » 17 Apr 2010, 11:39

Oh, gotcha. No, the transmissions are the same 4-speed until the 2000 (base) model S/V70. However, the wiring in the 96-98 models is different. I think the swap CAN be done, but the speed sensor is different on the earlier models, so it will flip out not knowing the right shift points.

I'll try to look at some things and get back to you. I'm sure they can be retrofitted to work. The straight swap, though, would be to get one from a 93-95 model.

Post by **wheelsup** » 17 Apr 2010, 15:38

IIRC you have to wire in the wheel speed sensor from the ABS to the transmission sensor. I think that was what was done. Since the speed sensor is just electrical impulses it takes it fine.

Sean-E-Boy · Post by **Sean-E-Boy** » 26 Jun 2012, 16:05

Would love to bring this topic back up. Anyone done it? What about the 5 speed auto into the 850?

Have been looking for ways to bring up the mpg, seems like this would help.

Post by **jimmy57** » 26 Jun 2012, 16:26

5 speed is a no go. It has a TCM that needs CAN inputs from ECM and ABS that do not exist on pre-99 cars.
96-98 are interchangeable and 93-95 are too. 93-95 has speed sensor on final drive case that is not fitted on the 96-98.