Auto Gearbox Question

On my car, the 'box hangs on to second when cold to force the cat up to temperature as fast as possible. Once warmed up it behaves normally. On a cold day it grinds along in second for quite some time - at least at town speeds.

Firstly, you should change the trans oil in the 850 boxes, despite it not being on the schedule. The lifespan of these boxes isnt much beyond 100k on one which hasnt had 20k changes. It is a known weakspot, you have been warned!!

Secondly, the selector position sensor is also a known problem, but you do not mention the Winter light flashing (indicating a fault) and it also seems to be temperature related, rather than jiggling with the shifter.

Start with a good flush and also confirm whether you get the W light flashing or not.

Although the box will tend to hold the lower gears and not lock up until the engine has warmed through, your post reads that it sticks in 1st gear on initial drive away??

Tim..

So does that suggest this is the correct behaviour? It may indeed be second gear that the car holds on to, rather than first (My mistake). What's annoying though is that when I want to go faster than town speeds, the car won't let me!

I will definitely give the 'box an oil change. Thanks for the advice. I don't get the flashing W light.

Perhaps I wasn't explaining it well: The car locks onto first (or perhaps second, I'm not sure), when cold. When it warms up all is well. Or, (and this is what confuses me) when I select "3" momentarily.

I doubt this is correct then, as driving faster than 30 would also warm up the cat quickly. Mine certainly changes up above second even when cold on the open road.

Right, definately the gear position sensor on the box I would say. Your dealer should know all about it.

A good flush and refill will help too, find a local garage who is experienced in flushing an auto box to do it, and supply them with 25litres or so of Dexron III from an independant oil merchant (eg Partco). Its about

FYI, on the 850 / 70 series you disconnect the return line at the oil cooler on the side of the radiator, conjure some method to direct the flow into a large bucket, have an assistant sat in the car to start and stop the engine, then with the engine running, pour in new fluid at roughly the same speed as that which is flowing out.

Stop pouring twice and let the box pump out the old oil then switch off, and refill with afew litres, and then pump that out.

Keep going until the fluid coming out is as cherry red as that going in.

Refill upto the low mark, then start engine, go for a ~5mile drive, then top up to the mark with the box hot.

Repeat every 20-25k or so. If you regularly tow, more often.

Tim..

Thanks to everyone for the tips and shared experiences.

My Haynes manual suggests Dexron IIe. Type II fluid seems to be a lot cheaper. What's the difference and is type II ok to use as well?

Type III hadnt been invented when the book was published probably! II or IIe will be ok if you change it regularly.

The original Volvo facotry fill is a type III grade FYI.

Tim..