Upgrading transmission

jboncher01 · Post by **jboncher01** » 22 Jun 2022, 08:54

Just a random question. is there a 5 speed automatic transmission out of the s70 that would be able to be used in a 850 GLT? And if so what all would be needed to make it work?

Post by **abscate** » 22 Jun 2022, 09:44

This swaps for you, Alex….

Post by **scot850** » 22 Jun 2022, 10:11

+I'm not sure how many times anyone would have done this. Most people try to avoid the 5 speed in some of the 00 year (last year) of the P80's and 01-02 P2's as they are seen as poor transmissions compared to the 4 speed that preceded it.

I personally have not minded the 5 speed auto transmissions and have now had 2 both of which have been ok so far. The biggest issue is the lack of maintenance as this was when Volvo was telling owners the trans were 'sealed for life' so no trans flushes were required. This often meant they only made it to 100,000 miles before starting to fail.

Now as to swapping, an engine is a much simpler thing to do than a auto trans of different types.850's read the speed sensors differently and they will have different TCU's. Wiring harness may be different as will be the engine management system and software.

I'm not sure about the 850's but the transmission type is programmed through the CEM (instrument cluster) and they must match or you can't read the TCU. Now on my 00 car, you cannot re-program the CEM and it will not recognize or work with a 4 speed CEM as I found out earlier this year. The other thing is that certainly the 98-00 CEM cannot be re=programmed even by a dealer. One shot is all they get. A replacement CEM mother board is ridiculously expensive and I don't know if an 850 one can even be programmed to recognize a 5 speed auto trans.

I am always happy to figure stuff out when no one knows the answers I need, but I'm not sure in this case I even want to try!

One question, why do you want to swap the 4 for a 5 speed auto trans in the first place?

Neil.

jboncher01 · Post by **jboncher01** » 22 Jun 2022, 10:16

More of a curiosity to see if I can get lower rpms when running on the highway and to increase mileage.

Post by **abscate** » 22 Jun 2022, 10:31

Much cheaper todo an M56 swap,and hire a free intern to shift for you.

Seriously, you may end up at the same final drive ratio with the 5 speed AT

jboncher01 · Post by **jboncher01** » 22 Jun 2022, 10:34

I have been looking into the manual swap as well. I think I found a good parts list on the site. Just need to see how hard it would be to source all of it.

Post by **abscate** » 22 Jun 2022, 11:00

Nice write up by bdub, I just bumped thst thread to add drivel about the shift cables

Post by **scot850** » 22 Jun 2022, 11:49

Um, where is your drivel?

I would check the 4 v's 5 speed final ratios. Not sure there is any difference or even enough to warrant the change. A manual trans swap if you don't mind shifting is an easier way to go.

I was on a US Volvo Facebook parts for sale/wanted website about a week ago and someone in Florida was selling parts for a P80 manual swap they did not have the pedal assembly:

Hope the link works! they also had a jewel headlight and sidelight set!

Neil.