Hi all. I have a great 1994 850 non-turbo wagon in excellent condition, that has always been well maintained. Currently has about 160k on it.

Late last winter/spring, it developed a slight tranny problem. When I first start it on a cold morning, it doesn't want to make that first upshift until it starts getting warmed up. ( I think this is 2nd-to-3rd running in eco mode?)

Once the weather warmed up, problem went away. I then did a fluid change and the tranny shifts smooth as silk in all situations.

Now weather cools down and problem is back, it just doesn't want to make that first shift. Once it does, it is pretty much all set until the temp drops again.

I'm getting no codes or warning lights, and it always shifts perfectly after the initial warmup. It has the correct fluid, at the correct level and it is nice and clean.

Do you think this is a solenoid? If so, which one, or should I just replace both of them while I'm in there?

I know I need a PNP switch as well, so I could have that done at the same time while the battery is out.

Any ideas?

Many Thanks!

 

You may be able to side step the problem by starting in WINTER mode. I think the main problem is the PNP switch. I'd start there.

 

Thanks so much for the reply. The PNP switch can actually cause faulty shifting?

 

If your fluid level is correct you have what is referred to as "morning sickness." Power steering systems get it too and for the same reason. Inside of your transmission the fluid moves pistons against spring pressure to compress clutch packs. These pistons are sealed by rubber lip seals. Over time these seals get hard and start to leak, causing the problem you describe. After the transmission warms up the lip seals become more pliable and the transmission starts working normally. It could also be the seals on the shift solenoids allowing fluid to leak past and not having enough pressure in the packs to fully engage.
Other than a rebuild the only thing to try would be an additive to try and soften up the seals. I've had good luck with Lucas brand and it's what I would try in your situation.