AWD Transmission: Transmission hesitates and clunks into D.

[eVolved]

Despite complete flush, New Volvo filter kit and Liqui Moli replacement fluid, my 2002 XC70 AW55-50/51 (98,000km), after showing a marked improvement to new for 6 months, has started showing symptoms again of the dreaded delayed and, sometimes violent, clunk into Drive (either from Neutral or P).

This is particularly annoying at traffic light stops. Is there a particular component in the transmission mechanism that is responsible for this area of gear change, such as the Neutral Safety Selector Switch? About to replace the transmission torque mount to see if this arrests the violence in the D gear selection change. Apart from this, the transmission gear changes (up and down, including kick down in overtaking, are silky and as sweet as a nut.

[Bashy]

What helped mine with the gearbox clunking was doing;

Gearbox flush, at least 50L went through the box over about 2 weeks
Changing the lower gearbox torque mount
Changing the top rear engine mount
Tightening the OSF hub bolt (that was very loose)

The above was done in that order too, whilst the flushes did help with the box flaring and the 3rd gear change, up and down, the clunking remained, it only improved when I did the last 2 in the list, its now about 95% good, I am happy at that, for now...

The only other thing would be changing the valve body, fairly big job, not cheap, although cheaper than a box rebuild i believe

[VOLVOBOY]

Hi.
`02 models are in the range for having issues with the Band D Servo. I assume you don`t know whether this has ever been replaced.
Search this forum on the subject to give you a "heads-up" on it. This is the lesser of two evils, the other is the pressure solenoids on the valve body being gummed up with crud.
Don`t leave this as it will ruin a good box in the long term. If the box is shifting sweetly then the clutches and shift valves are doing their thing. The issue is in the pressure control side and it`s usually the solenoids where the crud ends up.
The answer is to remove the valves and replace or dis-assemble and clean.

[Clan]

Originally Posted by eVolved

Despite complete flush, New Volvo filter kit and Liqui Moli replacement fluid, my 2002 XC70 AW55-50/51 (98,000km), after showing a marked improvement to new for 6 months, has started showing symptoms again of the dreaded delayed and, sometimes violent, clunk into Drive (either from Neutral or P).

This is particularly annoying at traffic light stops. Is there a particular component in the transmission mechanism that is responsible for this area of gear change, such as the Neutral Safety Selector Switch? About to replace the transmission torque mount to see if this arrests the violence in the D gear selection change. Apart from this, the transmission gear changes (up and down, including kick down in overtaking, are silky and as sweet as a nut.

Make sure you have the latest gearbox software too ...

[Willow place]

My Reverse has started to play up again (2003 2.4d) ok when cold and even warm , Hot about 10-20 second delay before it picks up the drive, touch the throttle before and there is massive bang, all mounts are still in good condition .

[eVolved]

Originally Posted by VOLVOBOY

Hi.
`02 models are in the range for having issues with the Band D Servo. I assume you don`t know whether this has ever been replaced.
Search this forum on the subject to give you a "heads-up" on it. This is the lesser of two evils, the other is the pressure solenoids on the valve body being gummed up with crud.
Don`t leave this as it will ruin a good box in the long term. If the box is shifting sweetly then the clutches and shift valves are doing their thing. The issue is in the pressure control side and it`s usually the solenoids where the crud ends up.
The answer is to remove the valves and replace or dis-assemble and clean.

Hi, I’ve owned the car since it was 2 years old, so, no the Band D Servo has not been replaced. Will research as you suggest. Have suspected possible servo issue, but have not been sufficiently schooled on this issue to fully understand this area of the car. You have sent me in the right direction so will study up. Thanks.

[eVolved]

Originally Posted by Willow place

My Reverse has started to play up again (2003 2.4d) ok when cold and even warm , Hot about 10-20 second delay before it picks up the drive, touch the throttle before and there is massive bang, all mounts are still in good condition .

I empathise. Mine troublesome but not that bad yet. Hopefully yours is recoverable.

[eVolved]

Originally Posted by Bashy

What helped mine with the gearbox clunking was doing;

Gearbox flush, at least 50L went through the box over about 2 weeks
Changing the lower gearbox torque mount
Changing the top rear engine mount
Tightening the OSF hub bolt (that was very loose)

The above was done in that order too, whilst the flushes did help with the box flaring and the 3rd gear change, up and down, the clunking remained, it only improved when I did the last 2 in the list, its now about 95% good, I am happy at that, for now...

The only other thing would be changing the valve body, fairly big job, not cheap, although cheaper than a box rebuild i believe

All really sound advice. Have already completed some of these and have new torque mount to install. Will follow up on your other points. Cheers.

[Georgeandkira]

A new Volvo filter kit, you say? It has always been written here that replacing the filter required removal of the engine/transmission combo and opening the transmission. Did you do this?

Given all the parts listed in the suggestions I fear a suggestion of adding a bottle of LubeGard (red bottle) will sound juvenile. I learned about it on an oil board. Lots of people use the stuff.

My '02 had a sloppy 2-3 shift. My B4 servo cover wasn't broken (not involved with your scenario). The PO had the unit flushed clean at a Volvo dealership long before I bought it. I had the TCM "reflashed" at a Volvo dealership and it helped.

However, the mechanic-in-a-can I mentioned above, greatly improved the trannie's shifting. I drove that car from 70K to 198K (as many here know) and the finicky buyer experienced no shifting woe.

Be aware that they make several products hence the "red bottle" specification.

Here's a link to an Amazon listing for the product:http://www.amazon.com/Lubegard-60902...omotive&sr=1-1

This is a USA listing for the photo only as I cannot upload pictures to this site.

[VOLVOBOY]

Hi.
Apologies...
`02 models are in the range for having issues with the Band D Servo.
This should read "Band B3 Servo."
This is not really related to your issue. It is more a 2nd to 3rd hard upshift problem but can affect the SLU Solenoid .

Just to try and give a bit of an idea as to how the gearbox works....
There are 3 duty or pressure solenoids
1. SLU Solenoid = this operates the engagement and release of the torque converter clutch ,the 2nd clutch (B2) and Reverse clutch (B3).
2.SLT Solenoid = this operates the line pressures.
3. SLS Solenoid = this operates the clutch pressures.
There are 5 Shift Control Solenoids
S1 = operates N to 1st and Reverse.
S2 = operates 2nd to 3rd and 3rd to 4th.
S3 = operates 1st to 2nd , 2nd to 3rd and Reverse.
S4 = operates 3rd to 4th and 4th to 5th.
S5 = operates Reverse.

So you can see that a hard engagement from neutral to drive could be to do with Shift Solenoid S1 , and any or all of the pressure solenoids.

These pressure solenoids take up the slack in the gearbox as it wears but they have a limited range. Once the wear is too great they can`t compensate and you start to notice slipping clutches and bad shifting.
Their operating range can be limited by being clogged with crud.

So now you have to make a decision ..
Do I clean or exchange the solenoids in the hope its all that`s wrong or is the wear already so much that new solenoids wont make any difference.

I think that your auto-box is in fairly good shape from your description. These boxes start slipping badly when they are in their death throes. The fact that you had it flushed and it didn`t start to slip afterwards is a good sign , i think.