XC70 No Drive

[Marke21287]

Hi Guys,

I recently bought a 2005 XC70 2.5T with an AW55-51SN gearbox.

The vehicle had no drive when I bought it and the previous owner gave me a toasted gearbox with the car. Story goes, that the original box failed so he bought a second hand box and installed it but 7000km later it failed again.
He sent the vehicle to a Gearbox specialist and they reconditioned the box. But it failed 1000km later with no drive.

I have stripped the original box and found ALL the clutch plates toasted.
I then took the box out the car and found one set of plates toasted and the box oil very dirty.

I have put new plates in the box throughout, completed all the settings as per the manual. I also stripped the valve body that was full of dirt, put new gaskets and rebuilt it with the aid of manuals so I am 99.9% sure it is all correct.

I installed the box I rebuilt plus a recon torque converter but I get zero drive from the box.
On inspecting the oil flow to the oil cooler, there is not a drop of flow. I have no codes logged with the ECM or TCM.

I pulled the box again and double checked the oil pump and everything is right but still no oil flow in the box.

I am at a complete loss. Any ideas or thoughts would be appreciated.

Thank you

[jonesg]

thats some serious work you've done,
is the trans pump running ?

[firstv70volvo]

Couple of initial questions; did reverse work? Is the transmission now out of the car or installed?

[firstv70volvo]

Hi Guys,

I recently bought a 2005 XC70 2.5T with an AW55-51SN gearbox.

The vehicle had no drive when I bought it and the previous owner gave me a toasted gearbox with the car. Story goes, that the original box failed so he bought a second hand box and installed it but 7000km later it failed again.
He sent the vehicle to a Gearbox specialist and they reconditioned the box. But it failed 1000km later with no drive.

I have stripped the original box and found ALL the clutch plates toasted.
I then took the box out the car and found one set of plates toasted and the box oil very dirty.

I have put new plates in the box throughout, completed all the settings as per the manual. I also stripped the valve body that was full of dirt, put new gaskets and rebuilt it with the aid of manuals so I am 99.9% sure it is all correct.

I installed the box I rebuilt plus a recon torque converter but I get zero drive from the box.
On inspecting the oil flow to the oil cooler, there is not a drop of flow. I have no codes logged with the ECM or TCM.

I pulled the box again and double checked the oil pump and everything is right but still no oil flow in the box.

I am at a complete loss. Any ideas or thoughts would be appreciated.

Thank you

I've attached a couple of pages from the manual VTL has, which shows the primary pressure feed circuits in the valve body. The pump is pretty straight forward, if there's nothing wrong with the fluid inlet suction through the filter (not clogged, both seals in place) the pump should suck fluid though the filter inlet path and if the inner pump gear keys are not sheared off the pump should output fluid to the valve body. Inside the valve body there's the main pressure and secondary regulators that feeds all the circuits.
Because you've inspected the pump and found nothing obviously wrong and the fact that the valve body was "full of dirt" I'm leaning towards a problem with the valve body. The valve body should have absolutely no amount of debris in it and I'm not sure what the dirt is in you've mentioned. No doubt you cleaned the valve body but the fact that it was full of dirt to begin with is not a good starting point and you'll need a known good valve body to get the transmission working again.
It's not clear to me, did you rebuild the original transmission in the car that originally had a no drive condition and all plates toasted?

From VTL's manual, pump and primary, secondary regulators

033.jpg (351.91 KiB) Viewed 146 times

076.jpg (271.38 KiB) Viewed 146 times

Pump, any problems with the pump or inlet suction path should be obvious.

51sn oil pump with gears installed.jpg (398.46 KiB) Viewed 146 times

[vtl]

I had a low pressure problem with my newly rebuilt transmission. Cured with a factory new valve body (GM). Comparing old and new valve bodies side by side, I found that I rotated just one plunger 120 degrees while rebuilding the old valve body.

Valve body is basically a wear item, it makes sense just to replace it every decade or so. It is not very expensive, $500+.