G/box: AW50151AWD: Gear Box codes and compatability

[Ollybee]

Hi
Having issues with my gear box not pumping oil.
I've found another gear box from scrapyard.
BUT I've been made aware i need to make sure i get the right serial numbers to do a swap..

My XC90 is 2004 D5 semi Auto and Gear box code is 55-51SN 30681190. (October 2004 first registered)

What other gear boxes would be compatible if i can't source exact box?

Thanks for your help in advance

[Tannaton]

Any AW55-51SN that was fitted to a XC90 D5/diesel should be compatible - however you may need to swap the wiring loom (including speed and temperature sensors) and actuator position sensor over from your own gearbox as the wiring and connectors were changed around 2004. This is a relatively easy job but you do need to remove the valve body cover and then reseal it, takes around an hour.

The same gearbox from a XC70 or V70 AWD will physically fit but I'm not sure if the final drive will be the correct ratio - it might leave you with a (even more) sluggish XC90.

When swapping the box, take great care to load the torque converter correctly when re-installing, this process is documented in VIDA and the Haynes manual, failure to do this will instantly damage the box on startup.

Also a good idea to get as much of the old oil as possible out of the new gearbox and torque converter by draining at different angles.

When installed - do the TCM adaptations process after about 20 miles, but as a minimum clear the adaptations memory. Don't make any judgement about the new box until you have done that.

Whilst doing the swap - it would be wise to replace the crankcase core plug, crankshaft oil seal, gearbox input seal and driveshaft seals at the same time. Also a good time to assess the vacuum mounts and front wishbones.

[Ollybee]

Thanks Tannaton
You seem very knowledgeable.

My original box, had an oil leak between box and engine so took it in for repair.
The mechanic changed seal and put gear box back in but oil still leaked.
So he tried again and this time fixed the leak... however on a 3rd test drive the car lost all drive...

checked box and seemed no oil was being pumped so was put down to oil pump in gbox...

I've been looking for a gearbox ever since... I found one yesterday and took it to Mechanic this morning but unfortunately the drive splines where worn away. So back on the hunt.

[Tannaton]

Originally Posted by Ollybee

Thanks Tannaton
You seem very knowledgeable.

My original box, had an oil leak between box and engine so took it in for repair.
The mechanic changed seal and put gear box back in but oil still leaked.
So he tried again and this time fixed the leak... however on a 3rd test drive the car lost all drive...

checked box and seemed no oil was being pumped so was put down to oil pump in gbox...

I've been looking for a gearbox ever since... I found one yesterday and took it to Mechanic this morning but unfortunately the drive splines where worn away. So back on the hunt.

No oil being pumped is one of the problems that you get if the torque converter is not installed correctly. There are a number of splined drives to engage, hence you have to spin the torque converter whilst pushing it into the gearbox - you will feel two clunks and see it drop in over 5-10 revolutions. When correctly installed the gap between the faces of the TC mounting flange and the bell housing flange should be 13mm. The last splines to engage are the oil pump drive...

You cannot remove and refit the box without removing the torque converter from the drive plate as it's impossible to re-install it correctly otherwise.

Hence - based on the limited information and in the absence of a full explanation - I suspect your bigger problem may be your mechanic...