AW55 50 SN Box compatibility

[jgjones095]

Hi all, UK owner here of a v70xc 2.4t auto 2001.

Are all aw55 50 sn boxes the same across all models of V70?
Or does the awd require a specific box version?
In the uk we also have the D5 engines so are the boxes the same in them as the v70xc's?

I've got a leaking rear crank shaft so the box will be coming off and it doesn't shift the best even after 5 years of nursing her for 30k miles.

Thanks all.

[Astro14]

My understanding is that the AW-55-50 SN is the FWD version and the AW-55-51 SN is the AWD version. While the valve body, clutches, etc, are the same between the two versions, the -51 has the extra gears in the differential section to drive the angle gear and the casting is changed to allow for the angle gear mount.

I really don't think that you can swap a -50 into an AWD setup, unless you want to simply delete the angle gear, and all the AWD stuff. You would need to get the FWD right hand driveshaft as well, as those are different parts between FWD and AWD. Not certain about the Left hand driveshaft...

I would bet that the gearboxes are the same between Petrol and Diesel. That is, a FWD (-50) box from a petrol would swap into a FWD diesel. And an AWD box (-51) would swap between petrol and diesel AWD cars.

In your case, the most certain course of action would be a rebuild of the box while it's off the car. This is a relatively common transmission, used in GM, Saab, Nissan, and Volvo models. Get the soft parts renewed and have the valve body overhauled. It won't be cheap, but "doesn't shift the best" combined with your year of manufacture suggests that it's time.

2000-2002 models of this transmission had a problem with valve body wear, particularly in the SLT solenoid bore. That solenoid controls line (hydraulic operating) pressure in the whole unit. Low pressure = poor shifting. The fix, generally, is valve body work, sometimes including a re-sleeving of that SLT bore.

As the owner of two cars with the same vintage of transmission, I've experienced this issue twice. In my case, addressed early, when the first symptoms began to appear, the transmissions were fixed by rebuilt valve bodies alone. The soft parts hadn't worn out yet. Both of those transmissions are still functioning well. My wife's XC has 229,000 miles on it. Still with the original transmission and its rebuilt valve body.

However, if the poor shifting has been present for a while, and since we are talking about a 17 year old transmission, I am going to suggest that a rebuild is your best option. You know, with absolute certainty, that it's the proper part for your car, and you'll know that it is completely renewed. A used transmission is just that: used. It might be great.

It might also be the reason that particular car was delivered to the recycler...

Before you give up on this transmission, it might be worth trying the two cheapest fixes: new B4 servo cover and complete fluid change. The cover was updated in about 2005. Your year pre-dates the updated cover, and a failed older design cover will cause shifting problems. You can find the updated B4 servo cover as a kit from your dealer (here in the US, it's readily available from the aftermarket). Search "Gibbons flush" on this forum for details on how to do a complete fluid change.

You'll need about 14 liters of compatible fluid for a complete fluid change. Please note: the dealer will sell you compatible fluid at an astronomical price. Any fluid meeting JWS-3309 is fine, including Toyota's own T-IV fluid, which is usually about 1/4 the price of Volvo's, and likely made in the same refinery. Idemitsu has come out with JWS-3309 fluid that might be relatively inexpensive in your market.

Were it my car, I would try cheap first, just to see if that fixes things...and if not, then it's off to find a good rebuilder...

[jgjones095]

Astro great advice didn't realise there was a aw5550 and aw5551!
Will go and check the box code now I have the car back fro the garage.

I've had the car for 5 years. There are signs the box has been opened before my ownership.

Ive done the cheep fixes over the years... fluid fluch and inline filter, changes b4 and solenoids.... all improved it 110% but she still flares now and again.
The next step is a valvebody changes but mine is the early design and I can only get a b version. .... which involves a slightly different wiring routine for the solenoids

[JRL]

Cheap fixes usually don't work on a 01 and an 02 because of what was written by Astro above.
It depends on EXACTLY what your issue it, if you have the latest software, and your mileage

[dejanaleksov]

Strange,I have aw55-50 sn witch is AWD with an angle gear its in a v70xc AWD cross country 2001.?