Transmission Issues -- GM Tranny in 3.0

[zonefive]

Car has 191,000 miles. Noticed that going up steep hills, whole car would shake and I had to put it in manual and shift to higher gear to keep it going.

Tried "Shudder Fix" but it had no effect.

Took car to transmission shop with thought it was the torque converter, but they say that is fine, their eval shows transmission is "losing pressure" under load because of a bad piston somewhere in the tranny itself. Does this make sense?

I authorized a trans removal so the problem can be precisely diagnosed. The shop has a really good reputation and they say they can repair the unit good as new, if the worn parts are limited. Otherwise looking at a used tranny.

Any advice would be appreciated. I know there's lots of threads but they seem to be almost exclusively about the ZF transmissions.

[Clavurion]

Perhaps he is talking about these pressure accumulator pistons.



If the box is taken apart I assume the torque converter is renewed or refurbished anyway as it's still the weakest link on this gearbox.

[andrewwynn]

With the symptoms that you are describing people usually do a moderate rebuild with replacing all the seals for the solenoid or do a whole valve body replacement or refurbish.

Yes and when one of my 2 X5 start acting like that I would be looking for a valve body refurbish.

[zonefive]

Well, the shop that told me it was definitely not the torque converter tore apart my tranny and found lots of gouging inside from metal shards, which was from a disintegrating torque converter, and quoted $3,000 to repair the transmission and replace the converter.

Mainly because I lost confidence in their ability to diagnose problems, I decided to go with a completely rebuilt transmission and torque converter from this place https://streetsmarttransmission.com/ for $2600 plus installation. So I'll pay about $500 more but they have a three year unlimited miles warranty, and every finite wear item in the new tranny will have been replaced.

I'll report back when the new transmission is in.

[zonefive]

Update:
Went with the Street Smart Rebuild. Their transmission failed on the way home (15 miles). Had to have the car towed back to the shop. Had the transmission replaced by Street Smart under warranty. Replacement tranny shifted fine but started to leak fluid from the bell housing within 100 miles.

Contacted Street Smart and they agreed to take the transmission back and provide a refund, and stop trying to deliver a non-defective transmission. The conclusion was that they could not do an adequate rebuild on the X5 3.0 transmission because BMW contracted with GM to make these units in a specific manner with parts that are not available to rebuilders. Street Smart was using Chinese crap parts to rebuild the transmission and simply could not deliver an OEM quality product.

Quoted $6,000 by an independent shop for a new transmission directly from BMW. Just couldn't do it.

Decided to source a used transmission, and found one with supposedly less than 50,000 miles about 100 miles away, for $500. Paid a shop $1,000 to remove the defective 2nd Street Smart one and install it. It was bad, slipped right away. That company agreed to take it back and shipped another one (I have no idea of the mileage). It worked and now I have about 3,000 miles on it.

Just took a road trip with the car and the car is now shuddering a little bit, especially at low RPMs, up hills. Just like the original one did before. Shifts fine. On a flat road, no issues whatever.

I want to have a car that I can confident in driving anywhere, anytime. So I want to address this issue. I am almost certain that the torque converter is failing. They probably all fail, because they are weak links in the tranny. Don't want to wait until the problem intensifies.

Options are a new $6,000 tranny from BMW or a rebuilt torque converter like this one https://www.partsgeek.com/gbproducts...xoCPW8QAvD_BwE

Are these rebuilt torque converters somewhat reliable? How do I know for sure that is the problem? Any suggestions? TIA

[Caryalon]

1. There's nothing "BMW specific" in the GM 5L40 which would prevent a quality transmission rebuild shop from rebuilding the transmission. These are GM transmissions, and quality parts are available from many sources.

2. I'm not sure why you lost faith in the original shop. Are they an ATRA or ATSG member shop?

Used transmissions are a crapshoot. There is really no way to know what you're getting.

So you paid a shop to remove, dismantle and inspect, but lost faith in them. I assume you paid them for their work? Then you bought a reman from a place online, and paid someone to install. That didn't work. Did you pay for the second R&R? Then you bought a used unit, wasn't good, Paid again for R&R. Then there was another R&R for second used transmission - not sure who paid for that.

In all of this, you never replaced the converter? Or you replaced it with the remain, but returned the remain and used a used converter with the used transmission? Didn't the reman come with a remain converter?

Now you're going to R&R again to do a converter or a BMW remain?

Do you have the original transmission?

Are all the mounts good? Has anyone checked the mounts/transfer case/diffs? Are there any codes in DME/EGS/4WD/ABS modules? Any dash warnings?

You need to go to a qualified shop that can diagnose what the problem is, not just buy more parts.

[c-bass]

@zonefive

Looking at your signature it seems like you're maybe taking your issues to the wrong people.

Like Caryalon said, there is nothing magical or special about these transmissions. The exact same transmission is used by other manufacturers like Porsche and Audi so this isn't even a BMW thing.

If you ask me replacing the torque converter is a MUST if you want a fully rebuilt transmission. There's a shop I've heard good things about that specializes in rebuilt and upgraded torque converters for these transmissions...but of course I can't seem to find the link for it anywhere. (I'll try to find it and update this)

If you plan to keep the car and want reliability then forget about the junkyard route. You're guaranteed to be playing a guessing game even if you pull a trans that works fine, you never know how long it will last.

Pay the extra and get a fully rebuilt unit with a warranty.

There's a shop in Toronto that I'm familiar with that does work for all the German dealers in the city and they charge about $3500 for a fully rebuilt transmission out the door with a warranty just to give you an idea of what it "should" cost give or take.

[zonefive]

1. There's nothing "BMW specific" in the GM 5L40 which would prevent a quality transmission rebuild shop from rebuilding the transmission. These are GM transmissions, and quality parts are available from many sources.

2. I'm not sure why you lost faith in the original shop. Are they an ATRA or ATSG member shop?

I lost faith because they told me initially before taking the transmission out that there was nothing wrong with the torque converter. Then when they got the thing out and inspected it, they told me the torque converter has grenaded itself and ruined the transmission. This is the shop: MIRAMAR TRANSMISSION - Miramar Transmission & Auto Repair

Used transmissions are a crapshoot. There is really no way to know what you're getting.

So you paid a shop to remove, dismantle and inspect, but lost faith in them. I assume you paid them for their work?

Yes, I paid everyone for their work. I'm not sure why it matters who paid for what, but I don't mind answering

Then you bought a reman from a place online, and paid someone to install. That didn't work. Did you pay for the second R&R?

Street Smart paid for the installation of the second reman transmission

Then you bought a used unit, wasn't good, Paid again for R&R. Then there was another R&R for second used transmission - not sure who paid for that.

In all of this, you never replaced the converter? Or you replaced it with the remain, but returned the remain and used a used converter with the used transmission? Didn't the reman come with a remain converter?

The reman transmissions both came with a remanufactured converter. I never thought, nor was I advised, to combine a reman converter with the used transmissions. Probably would have been a good idea.

Now you're going to R&R again to do a converter or a BMW reman?

Correct

Do you have the original transmission?

No, the original transmission was shipped back to Street Smart as part of the core exchange.

Are all the mounts good? Has anyone checked the mounts/transfer case/diffs? Are there any codes in DME/EGS/4WD/ABS modules? Any dash warnings?

There are no codes at all. The transmission mount was changed with the transmission. The transfer case was changed 45,000 miles ago. Can the diff cause these symptoms?

You need to go to a qualified shop that can diagnose what the problem is, not just buy more parts.

Problem is finding a qualified shop. One I went to had stellar reviews and either lied to me about the torque converter being good or didn't know what they were talking about

[upallnight]

Since your old trans grenaded and left a lot of shrapnel in the trans, you will need to flush out the trans cooler in the radiator or replace the radiator. Could be the leftover shrapnel in the trans cooler is causing the problem.

[zonefive]

Originally Posted by upallnight

Since your old trans grenaded and left a lot of shrapnel in the trans, you will need to flush out the trans cooler in the radiator or replace the radiator. Could be the leftover shrapnel in the trans cooler is causing the problem.

No, they did a thorough flush so that isn't the issue