2003 V70 Transmission Swap Questions

unggthat · Post by **unggthat** » 13 Nov 2020, 19:07

Hey all,

I haven't done much Volvo foruming(can I make that a verb?) since being a significant poster on Brickboard back 15 or 20 years ago...but here we are with newer Volvos!

Anyways, my 2003 V70 with 278k miles has started making noises that I thought was a wheel bearing. Replaced the bearing. Noises still there. Driveshafts are replaced, too. The sound is similar to a wheel bearing and gets worse when warm. Rumbling and a faint, intermittent whirring when slowing down. A rather constant grinding-ish noise.

So I'm pretty sure with all these miles (I replaced the trans fluid when I got it at 210k), there's a bearing going out inside the differential part of the transaxle. If anyone has any other brilliant ideas of what to check, let me know. I can't think of anything else at this point.

But that isn't my real question. I'm starting to plan out putting a used trans in the car. Beyond the obvious replacing of fluids and such, are the any other items I should definitely replace while I am in there? My biggest question right now is this: with a swapped transmission, do I need to have it specially programmed at a dealer? Indie Volvo shop? Or can I just hook up the electrical connections and go?! I have a decent reader but not VADIS.

Thanks for any help or advice! This will be my first FWD transmission swap, so I'm making sure I'm ready!

Post by **darrylrobert** » 13 Nov 2020, 19:20

I assume its an Automatic? If so there is a post/section somewhere on here thats dedicated to the numerous problems with these units. I have a stick volvo and a parts car auto, i would say you need to keep most if not all the electronics and just swap the mechanical parts. Having said that from what i have heard the electronics can also be your problem most electronics need programming to work.

Post by **firstv70volvo** » 14 Nov 2020, 09:26

Here's what I found out when trying to find a used transmission to swap in my 2001 Volvo V70 T5. I bought a used transmission from LKQ on Ebay and planned on rebuilding it before install but it wasn't compatible even though the compatibility information said it was. My car has an AW55-50SN and the transmission I purchased (from a 2004 S60 T5) was an AW55-51SN. During disassembly of the 51SN transmission I found differences in number of teeth on ring and sun gears and the final drive ratio was also different. The 51SN has slight differences in gear ratios and I didn't know for certain if this would cause gear ratio errors so I contacted Level 10 transmission in NJ. I talked to Pat there and he was very helpful and answered the questions I had, great guy. He confirmed the gear ratio differences and he didn't recommend using the 51SN in my car.

Bottom line, don't trust the compatibility information provided, in my case I think a 2001-04 V70 T5 transmission would have worked but not the 2001-04 S60 T5. The cost is higher and availability lower for the V70 transmission though. After 2004 all the electrical connectors changed design. I ended up rebuilding the transmission in the car to be certain of compatibility even though it took some new tools and an extra couple of days to get my car back on the road.

My advice would be to stick with the V70 (50SN?) transmission and same engine, turbo, non-turbo, T5 because the the final drive gear ratio may be different. Also, you're going to find these older transmissions are going to have a lot of miles on them so finding a good used one may be difficult. You might consider a rebuilt/rebuilding the one in your car if there's not a lot of hard part damage. Cost and time involved in doing this but it's a lot of work to remove and install the transmission and you don't want to have to do this twice. It took me 4 1/2 days, 2 days for removal and install and 2 1/2 days to rebuild the transmission. I also had the torque converter rebuilt and the adapt mode reset.

unggthat · Post by **unggthat** » 15 Nov 2020, 10:00

Thanks for the replies! First, I should've mentioned: it is a NA automatic. I can find a few used transmissions close to me from V70s. As this car has 278k, I am hoping to keep the costs lower, so I'd rather not pay to get a rebuild. My current trans worries me with the grinding noises...if I need a regular rebuild plus a bunch of parts for the differential, the costs are going to be high.

To get the adapt mode reset, is VADIS required?

Thanks again!

Nate

Post by **SuperHerman** » 15 Nov 2020, 12:40

VADIS has the feature - other scanners also have it. Theoretically you can just not do it and let the transmission computer sort it out over time. I have done this on a few vehicles.

RE rebuilding - a grinding noise is never a good sign as it hints at a hard part mechanical failure. It could be a simple as a bearing that is normally part of a replacement failing or another more expensive hard part. Is it the transmission or differential?

As to what transmission works - two items. A transmission is two pieces - the actual gears, clutch packs and related and then the valve body. The electronics (solenoids) are in the valve body (which is separate from the transmission computer). In your instance you may only need the transmission and not the valve body (which if in perfect working order could just be moved over).

Second part - look up part numbers. That will tell you what will and will not work. Three main ones to focus on -- Transmission Computer, Valve body, and transmission (you may find only valve body and transmission listed as a unit so you have to dig deeper).

unggthat · Post by **unggthat** » 04 Jan 2021, 20:47

An update for all of you helpful people: I'm in the midst of round two. As money is an issue and I had some extra time, I got a used tranny with 118k on it and put it in. Took about 16 hours total, I'd say, to get the old one out and new one in. It didn't work--flaring really bad going into gear, etc. I had put a new B4 servo cover on, changed the front seal, and got some rebuilt solenoids that I put in. Don't know if somehow something I did messed it up or if it had a plugged up internal filter...

Anyways, the wrecker honored their warranty and gave me another one. I'm about to put it in the car. I didn't change the solenoids this time or the B4 servo cover, in fear those somehow messed it up. I did change the front seal. We'll hope round two is a charm! Any bits of advice on how to make sure this one works?! Ha.

And FYI, for a NA 2003 V70, the correct transmission is an AW55-51SN.

Post by **SuperHerman** » 04 Jan 2021, 22:02

You could try swapping out the entire valve body if you have not yanked the transmission again.

Use your original valve body in the new transmission and see what happens.

There are four or five variations of the valve body denoted with "no letter", A, B, C (not sure if there is a D). I am no expert, but as I understand it if one switches the letter to a different one a software reprogram of the transmission computer is needed. Maintaining letter of valve body should not be an issue, but an adaptation reset is best practices.

Post by **firstv70volvo** » 05 Jan 2021, 09:40

unggthat wrote: ↑04 Jan 2021, 20:47 An update for all of you helpful people: I'm in the midst of round two. As money is an issue and I had some extra time, I got a used tranny with 118k on it and put it in. Took about 16 hours total, I'd say, to get the old one out and new one in. It didn't work--flaring really bad going into gear, etc. I had put a new B4 servo cover on, changed the front seal, and got some rebuilt solenoids that I put in. Don't know if somehow something I did messed it up or if it had a plugged up internal filter...

Anyways, the wrecker honored their warranty and gave me another one. I'm about to put it in the car. I didn't change the solenoids this time or the B4 servo cover, in fear those somehow messed it up. I did change the front seal. We'll hope round two is a charm! Any bits of advice on how to make sure this one works?! Ha.

And FYI, for a NA 2003 V70, the correct transmission is an AW55-51SN.

There are some things you can do to check out the second transmission. What's the history from the salvage yard, the history of the car it came out of, was it driveable and the transmission was working before being pulled. Was the car badly wrecked and this is why it ended up in the yard, which I would consider a better scenario, an undamaged car may have been there because the engine or transmission were bad. Mileage, fluid condition?

You might also consider pulling off the bellhousing side case, which is more work but gives you the opportunity to replace the filter and inspect the condition for part of the transmission. It involves removing ~15 bolts for the case, 8 bolts for the pump, tapping the case to separate, cleaning, resealing and reassembly. If you do decide to do this let me know as there are some things to make assembly easier and things to watch out for, such as not removing the pump or if removed align and engage the two clutch packs hubs prior to reinstalling pump/clutches assembly with the transmission upright.

I hope the second time it works out for you, that's a lot of work to pull and install the transmission.

unggthat · Post by **unggthat** » 03 Mar 2021, 19:05

Just to conclude here--the second used transmission is in the car and working perfectly. I spent a long time making sure the fluid was fully flushed and at exactly the correct level while the fluid was at 40 degrees C. Though I didn't take the plunge and remove the bellhousing side case, I'm confident everything is working right now. The second time went much faster than the first, for what it's worth...

Post by **SuperHerman** » 03 Mar 2021, 20:33

Could you summarize what worked and what didn't work transmission wise? Was the first replacement the wrong part or a bad transmission? What year was the working donor?