S80 T6 p1618 p0751 - tranny problem

Boeingpilot · Post by **Boeingpilot** » 09 Apr 2016, 04:21

Hello,

I'm new in the forum.

I bought a Volvo S80 T6 1998 with urgent transmission service required on the dashboard. I thought it was only a regular service that was required and then resetting the light.

But off course I was wrong. After driving a bit the transmission jumps in to limp mode. I gave changed the gearbox oil and also the filter. Omd codes showing are p1618 and p0751.

I notice that it shifts very good from 1st gear until 3th gear, but between 3-4 it takes some time for the gearbox too change.

Any ideas what it could be? And in worst case is it possible to bypass limp mode?

Kind Regards,

Erik

Post by **MadeInJapan** » 09 Apr 2016, 07:08

Unfortunately, many of the older model (up through 2001) S80's had a lot of transmission issues. My mechanic has on his garage floor at least 8 old transmissions that he's swapped out for good ones from S80's in particular but also 2001 S60 and V70 models. I hope your transmission isn't shot and that it's some solenoid issue but my gut tells me that your transmission may be toast. These models are notorious for that. Also, on an older transmission, changing out the fluid is not typically the best thing to do. If you want to do that, a "drain and fill" where you do about 2 quarts at a time, drive it for a few hundred miles and repeat the "drain and fill" again several times is the best way to go. Changing the fluid all at once often gets things stirred up in the transmission that end up clogging passages. I'm sorry if I'm being a pessimist but no matter if a shop (and Volvo won't do it anymore) says they can rebuild a transmission, I've never really seen it successfully done. If your transmission is truly bad, your best bet (if you want to keep the car) is to swap a good one out for it- try to figure out what the newest model that will fit it would be. Good luck and please report back as to what you find and what you decide. I'm hoping for your sake that the transmission isn't on its way out and you find a simple, not expensive solution to your problem.

Addendum: It would be worth your while to search our forum here for similar transmission issues with your model. Here is a thread I found that may set you in the right direction: https://www.matthewsvolvosite.com/forums ... on#p351959

Boeingpilot · Post by **Boeingpilot** » 10 Apr 2016, 05:09

Thanks a mill for your reply. I already changed the atf and filter.

I seems to shift a bit better 3-4 but still ends up in limp mode. Without any experience from trannys I might think it could be a disagree in the computer because of the delayed 4th gear shift.

Is it possible to permanently disconnect the limp-mode function(by-pass)? I could live with a slow 3-4 shift

Kind regards Erik

Post by **MadeInJapan** » 10 Apr 2016, 08:19

I don't think that is possible without a computer hack. the Volvo ECU does this to keep you from damaging things any further. Because you are in Gothenburg I would say that there are some good Volvo mechanics in your area that are familiar with this transmission and its problems. Search for them- not necessarily still working for Volvo, and see what they say. Good luck with this- I know that it is very annoying and you want to drive your car without issues as soon as possible! I just know that in the U.S., all of the "transmission shops" that say they can fix Volvo transmissions are just ready to take your money without any true repairs- they just can't do it.