2002 C70 Transmission bumping, harsh shifting

goldmandan · Post by **goldmandan** » 26 Aug 2015, 17:46

I brought this up again because I finally got the headgasket replaced and the car runs excellent again now........ I started driving it again and at first when engine is cold the transmission shifted nice and smooth. After driving about 20 miles or so it started shifting erratically. When downshifting as you slow down it would slam the gear into the lower gear only SOMETIMES. Sometimes when going at slow speed it would feel as if it was shifting into 1st and you heard a loud knocking noise. That was probably the engine bucking on the mounts but it was not fun! I went back to the shop, checked the trans fluid level and found it at "full cold" so I added about 1/4 quart or so and took it for another drive. Immediately it seemed to smooth out........ the real terrible bucking and harsh shifting was gone but there's still just a bit left.

Here's what i've done so far:
checked for codes.......... nothing........... after driving 40 miles today, hooked up Autel Maxisys Pro scanner....... no transmission/powertrain codes
drained out about 4.5 liters of trans fluid, poured in new Toyota IV transmission oil.
rechecked fluid level today, a bit low...... added about 1/4 quart.

Anybody have any ideas? I was talking to one of the techs at the dealer and he said it could possibly need programming as 2002 had a TSB about needing a software upgrade.

Any ideas or anyone have the same problems??

goldmandan · Post by **goldmandan** » 27 Aug 2015, 06:05

Post by **tryingbe** » 27 Aug 2015, 06:49

Get it programmed first.

Post by **Homebrand** » 27 Aug 2015, 07:37

If the issue occurs once the transmission has warmed up, as seems to be the case it could be an issue with the linear solenoids.
I refurbished mine and it solved it perfectly.
Search this site for "shift flares" - "valve body" repair etc.
But also get the software checked first to eliminate it as a cause- however I don't believe it's the problem as you shift fine when cold but harshly when warm.
Check my posts on this issue with background which I primarily learnt from precopster and others on this site.

EDIT: because my issue was caused by sticking solenoids from gunk in the bushings it was a "mechanical" issue so it never showed codes with Vida/dice either.

goldmandan · Post by **goldmandan** » 27 Aug 2015, 08:56

I drained and filled once. 4.5 liters came out and put 4.5 back in....... the color was just "medium red" and there was no sediments in it to indicate any type of metal shavings etc........ I also read about draining and filling 2-4 times in intervals to get all the old fluid out of the trans/converter..... will try that also as last night when I had driven it for 30-40 miles I came back to the shop and found the fluid to be at "full, cold" so I filled 1/4 of a quart and it immediately shifted smoother..... so it may just be fluid level related..... I will check and report back........ $137 to just scan the car at Volvo seems a bit steep!

Post by **Homebrand** » 27 Aug 2015, 10:04

The dealership is expensive.
For what it's worth. My fluid was not gritty, I had no sediment/sludge in it to really indicate that it could foul the solenoids. The magnetic drain plug was also clear of any metal deposits.
When I refurbished the solenoids by clearing the bushings, it was almost indiscernible as to what was causing the armatures to stick. But they were sticking.

It can take quite a while for the fluid to warm up to the point where the solenoids start acting up.
Mine was intermittent. At one stage I thought I had fixed it as I drove 150kms with no problems, but as soon as I got in stop/start traffic and the temp hit about 80c the issue was back (I used my Dice setup to monitor the exact transmission fluid temp).
It wasn't every up or downshift, just some of them. It was random.

If the fluid levels are right and it plays up when warm then my money is on sticking solenoids.

When the cars hot, how are your garage shifts? From P to R to D etc? Are they smooth, fast and non clunky?
Mine eventually became clunky and delayed.
Also are you getting any flaring (revs before slamming/bumping into gear) on up shifts.

goldmandan · Post by **goldmandan** » 27 Aug 2015, 16:04

I will try to get some seafoam for transmissions and run that with the Toyota IV I have in it right now. Run it for about another 30-40 miles and dump it out and refill with new fluid. If all else fails I will need to get a hold of a rebuilt valvebody as i'm in a time crunch to get this car finished and gone... how easy is it to get the valvebody cover and valvebody out. I know the instructions talk about dropping the subframe etc etc....

Post by **Homebrand** » 27 Aug 2015, 20:18

It's not too difficult. Just very tight space to get the cover etc off.
I found the trickiest part was getting the valve body cover back on without fouling the RTV (sealant) although I believe there is a gasket available.

Post by **Homebrand** » 27 Aug 2015, 20:31

BTW You could just rebuild the solenoids.
Transgo kit is about $120 USD.
Check my other post with Hiriams video in it.
I'm using tapatalk so don't know how to link here.

goldmandan · Post by **goldmandan** » 28 Aug 2015, 06:58

So it IS possible to remove the solenoid cover without dropping the subframe and all that extra work? I KNOW there is a gasket for it...... I have seen them on Ebay. So you are saying that you have or someone you know has removed the solenoid cover and valvebody without dropping the sub frame?

Thanks!