2005 TRANSMISSION FAILING.. MODLE # A5S 390R YZ

[Lost puppy]

2 Years ago I bought a 2005 X5 with 122,000 miles on it. Now It has 166,000 miles on it. For the past few months my service engine light has been on giving me fault codes about misfires and running to Rich or to lean bank 1 bank 2 etc and other engine related codes. yet the engine ran fine. The alternator completely died about 3 weeks ago and after I replace it I cleared the fault codes and everything was good. Two days after that I got a fault code of p0735 stating "Gear 5 incorrect ratio". The transmission started to slip and not go into 5th gear and it would go into fail safe mode. I shut off the engine for a few minutes and then start it again the fail safe mode light will be off and I can drive it like normal however it will not go into 5th and then it goes back inyo the failsafe mode and now I have lost reverse. My question is did the low amperage or voltage output from the alternator wipe out any of the electronics in the transmission. What would be the best way to go on fixing this problem?. Do I replace the transmission with one from the dealer at $5,000. Which would include the torque converter but not the 10 quarts of lifetime fluid at $500.00
Have my transmission rebuilt at $4,500.00
Get a rebuilt one from a parts house that I don't know a thing about it for under $2, 000.00 or so and hope it will work and for how long because I don't want to go through this again down the road. Has anyone experienced similar problems with their transmission please let me know because I'm thinking of replaceing or rebuilding it. Or am I thinking the wrong way and not seeing something. Any input on this would be greatly appreciated.

[Caryalon]

Has anyone done an initial diagnosis on the transmission?

A couple of points:
1. There is no such thing as "lifetime" fluid.
2. Even BMW fluid is not $50 a liter.
3. There are options besides a dealer or parts house. Have you considered an ATRA member transmission shop with good reviews on Google/Yelp?
4. Gear ratio error codes could be signify low fluid, but could also (and probably are, at 166 k miles) a sign of internal wear.
5. While these cars are very sensitive to low voltages, if the charging system is good, I'd doubt that you fried anything from that alone.

[EODguy]

Check your transfer case motor gear as it probably needs to be flipped, when you're checking the fluids (transmission/transfer).

Sent from my SM-A730F using Tapatalk

[andrewwynn]

We had a Mercury sable that had a defective solenoid for torque converter lockup. The symptoms sound identical.

We would get a code related to the transmission slipping in high gear on long drives.

You can tell if the transmission is not locking up by getting up to highway speed and then slightly accelerate from say 55 to 58 mph. The tach should barely move. If the tach rises and settles back down, transmission is not locked. This could be the actuator or the torque converter.

[c-bass]

Originally Posted by andrewwynn

We had a Mercury sable that had a defective solenoid for torque converter lockup. The symptoms sound identical.

We would get a code related to the transmission slipping in high gear on long drives.

You can tell if the transmission is not locking up by getting up to highway speed and then slightly accelerate from say 55 to 58 mph. The tach should barely move. If the tach rises and settles back down, transmission is not locked. This could be the actuator or the torque converter.

The ZF tranny in my e46 330 has the solenoid issue

In the case of the ZF tranny the issue is generally not with the solenoid going bad as much as there is a seal in the torque converter that won't allow the tranny to hold the necessary pressure to engage overdrive.

Unfortunately there is no way to service this part as it's inside the torque converter.

If I was in your shoes I would first start off by scanning the codes with an ODB reader. A cheap amazon bluetooth device will give you a better idea what is going on.

Next up I would check the fluid level, which is a pain in the ass because there is no dipstick. you would have to get the trans up to temp and then check the fill hole. There should be a slight dribble of fluid coming out if it's at the proper level.

A transmission fluid flush and filter change can definitely help as there is NO SUCH THING AS LIFETIME FLUID.

Failing that, you would have to decide how long you want to keep the car for and "invest" accordingly.

A good friend of mine who is a mechanic went the used transmission route...twice, before he bought a brand new one from the dealer and called it a day.

If you want to keep the vehicle around for a while then I would seriously consider a new or fully rebuilt (with warranty) unit.

If you're uuhhh....let's call it adventurous, then swapping transmissions can be a fun way to spend many hours

For transmission fluid many many people use the Valvoline Maxlife with great results. No need to buy magic BMW fluid because these are GM and ZF transmissions found in many non magical cars.

Good luck

[andrewwynn]

If there is a rubber seal involved, ATP AT-205 is specifically designed to deal with that problem. I used in the crankcase of my m54 to basically stop the oil leak that was "getting out of control". (I can wait until the weather is nice to find and fix the leak now).

Before rebuilding a transmission, I would definitely try at-205 first.

[Lost puppy]

Originally Posted by Caryalon

Has anyone done an initial diagnosis on the transmission?

A couple of points:
1. There is no such thing as "lifetime" fluid.
2. Even BMW fluid is not $50 a liter.
3. There are options besides a dealer or parts house. Have you considered an ATRA member transmission shop with good reviews on Google/Yelp?
4. Gear ratio error codes could be a significant low fluid, but could also (and probably are, at 166 k miles) a sign of internal wear.
5. While these cars are very sensitive to low voltages, if the charging system is good, I'd doubt that you fried anything from that alone.

No I didn't have any professional mechanic look at it. Reason being is I did not want to drive to their shop not knowing what the problem is I did not want to make matters worse. This is my second X5 but it's the first time I've experienced this type of problem.

The more I think about it and the way the transmission is acting it is very likely that the fluid is low.

So here's the question if it is low what synthetic transmission fluid do I add to it?. If adding fluid will correct the problem then yes I will go ahead with the service. Especially with that many miles on it.

I do appreciate your input and I thank you very much. I will try the things you've suggested and go from there.

[upallnight]

You have the "GM" transmission 5L40E so Dexron III was the original transmission fluid for the trans. Dexron is no longer available but Dexron VI is the new fluid being used. Unless you do the fluid change yourself, you will have to leave the X overnight with the mechanic/shop. The temp of the fluid can't exceed a certain temp if you want to get the correct fill level. Blame this stupid fill method on the engineers or bean counters at BMW for not including a dipstick for the trans, but coming up with this stupid procedure instead. You would probably like to have the filter replace at this time. Just remember a lot of old trans fluid is retained in the torque converter.

[c-bass]

Originally Posted by Lost puppy

No I didn't have any professional mechanic look at it. Reason being is I did not want to drive to their shop not knowing what the problem is I did not want to make matters worse. This is my second X5 but it's the first time I've experienced this type of problem.

The more I think about it and the way the transmission is acting it is very likely that the fluid is low.

So here's the question if it is low what synthetic transmission fluid do I add to it?. If adding fluid will correct the problem then yes I will go ahead with the service. Especially with that many miles on it.

I do appreciate your input and I thank you very much. I will try the things you've suggested and go from there.

Many people use the Valvoline Maxlife ATF

https://www.valvoline.com/our-produc...ti-vehicle-atf

The transmission fill procedure is not complicated at all.

You need to have the transmission at normal operating temperature and when you unscrew the fill plug there should be a slight trickle of fluid coming out.

If you are worried about driving the vehicle then let the engine run until it comes up to temp (needle in the middle) and shift into each gear for a few seconds. R N D etc. Then check the fluid level.

Basically the trans fluid will expand when heated (like most fluid) so if you fill the transmission to the proper level while it's cold once you're driving around the fluid level will be too high.

The transmission shop that I deal with specializes in European cars and while I had my car there for a flush I was asking the guys all about the pain in the ass fill procedure. They said it's not that sensitive and proceeded to walk me through it on my car.

If you read how to do the fill procedure from the manual it sounds a LOT more complicated than what it really is.

[FellowsheepTech]

Following...
My son's 2003 3.0i (230k) started throwing the same code (4th & 5th) and constantly going into limp mode not too long after I changed the driveshaft (after 2nd center bearing failure). I haven't had a lot of motivation to dig into it, but now thinking another fluid/filter service with the ATP AT-205. I've done the trans service twice before on it, but has been 50-60k since the last one. The first time I replaced center bearing I very carefully topped off the trans, so doubt it's just low.

BTW, we also had bank 1/2 codes a while back & it was due to gunked up CCV. I went the delete route following a post in another forum for E39. The "delete" was replacing the valve assembly with a PCV filter & various plugs/hose routing. Engine loved it!