Hi Folks - I recently acquired a volvo 850 (10 valve) in mint condition with only about 35000 miles. It has a build of Aug 1994 but a VIN with the S code of 1995 - Volvo confirms with me that it's a 1995.

Soon after I bought it I noticed an intermittent problem with the auto transmission. Every now and again when you put the car into drive from P,R or N positions, it fails to engage properly until revved a bit (~1300 rpm or so) and then it bites in with a bit of a jerk. It moves really slowly before it engages with the jerk, so some power gets through.

Once it's going it is absolutely flawless in any gear, kickdowns perfectly, and goes like a dream.

I pulled fault codes out of the diagnostic system - 223, 134 and 313. I cleared them over two weeks ago and no codes have returned, despite the problem showing itself quite a number of times since then.

The ATF fluid is at the right level, and all the people I have seen have said that I would just waste money to change it, or that it is "not too bad" and have not recommended changing the fluid yet. It is brown but smells more like normal ATF than stuff that has been toasted.

The problem only tends to show itself when the car is warm, eg you drive it for ten minutes, park, then when you get back in and go to drive away, then it shows itself...

The main problem is the varied answers I get to the cause of the problem!

Tranny specialist #1 checked it out and stated that an "A" front clutch drum develops linear weld cracks, (or cracks along a linear weld?) and the solution is expensive - entire replacement of the tranny supplied from Volvo. The codes meant nothing & replacement of the parts would not fix it, according to him. When he drove the car he must have given it heaps because the problem was bad whenever I put it into neutral during this session of driving - until the car had a chance to cool down completely.

Another day and a second transmission specialist said that there was some sort of a piston in the transmission and its rings (to continue the analogy) were allowing ATF to leak past. It wasn't due to cracks in the front A drum. The solution was a tranny rebuild- almost as expensive a quote as for the replacement. He only saw the problem once and didn't exacerbate it with his test drive, thankfully.

Opinion 3: I took the car to a volvo specialist who stated that they had nver seen a mechanical problem with an 850 transmission and it was likely to be just the gear position selector-and they had changed many of these.

So perhaps the beginning of the solution to this is to get the gear position selector changed. I just thought I would post this message in case some knowledgeable volvo fanatic out there recognises the real problem from the symptoms I describe and can say what it is - without me replacing gear or throttle position sensors, or whole transmissions, unnecessarily.

Thanks in advance

Michael