C70 S70 V70: Transmission problems - solutions

[yevgeniy]

I know this has been chewed out by many, but nobody usually says what actually fixed their transmission problems - here is my story -

About a month ago i found a 2001 Volvo C70 Convertible for 2500$, it has 125k miles. Sounds too good to be true? exactly what i thought, and well on a test drive i knew the transmission was going out. ( keep in mind that the only volvo i ever had was a 1986 740 GL) and that was a long time ago. I was hooked as soon as i saw it , and simply knew that it will be my next project.

Here are the problems and things done.

When the car is cold it shift perfect, but as soon as it warms up it would start flaring on up-shift from 2nd gear into 3rd, and 3rd into 4th. after few more minutes of driving if would SLAM into all the gears with such force that it shook the whole car. after another 10 min of driving if would not downshift from a 3rd gear sometimes and stall out the car.

1) I decided to try AT fluid first - flush made no difference , then i started looking at forums - found out that the shop used Castrol 3309 , and it needs Mobil 3309, so i put a bottle of Lucas stop Slip additive ( i normally am against those, but i figured can't harm it any more). this seemed to resolve the problem for a few miles . and then it was back to "normal". Called Volvo dealer they said a new transmission was needed, took it to transmission shop, they checked for codes - none popped up. their answer was "Needs complete rebuild"

2) Learned about software update and B4 Servo Cover, decided to do two at the same time, took it to a local Volvo Only shop, Mechanic that drove it, and looked at software came back saying that TCM has the latest software, and B4 Servo Cover has been updated. I told him to go ahead and put in a new B4 Cover. On way home i noticed something interesting, although it still slammed into gears, it did it at the somewhat right time, and it downshifted from 3rd as was needed. when i got home i took a closer look under the hood, the top torque mount seemed a little worn.

3) Got a new top torque mount, when i took the old one off it has simply fell apart! It looked OK when installed. So i figured it needed to be done anyway, New mount went on........ here is the kicker .... IT STARTED SHIFTING SMOOTH!!!! now i knew about possible vibrations from broken torque mounts, but how transmission being warm has anything to do with it? well, i opened a hood, and it was insanely hot - the mount - more so than i imagined. rubber gets soft when warm - sooo simple huh?

4) this is unresolved - after a much longer drive i get a hint of hard shifts, not nearly as bad as it was. So i will purchase a new lower torque mount and do believe that it will make a big difference.

5) this is unresolved - Still get flares on 3rd gear - as i get a bit more money i'll go ahead and flush the transmission with the Mobil 3309

I will report on progress and what made the biggest change as i go along - but at this point i am 80% positive that a new transmission will not be needed. and that a lot of people replaced or rebuilt their transmissions for no reason - so far the repair rounded to 250$

Sorry for a long post, but i wanted to be clear on the problems, hope this post helps someone.

Anybody has any more ideas about this? please let me know. I am an amature mechanic, so far restored 1984 MK1 Volkswagen Cabriolet, 1995 VW Cabrio, 1995 BMW Cabrio, and now doing a Volvo. as much as i like it i think it will not be my last