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2010 GLK350, 2021 Taco, 2019 Lexus GX460, 2009 BMW 335d, BMW 328xi
2010 GLK transmission
Just picked up a 2010 GLK350 4-matic as a project for my daughter and I. Mileage is around 150k, PO says a European specialty shop said it needed a new transmission. Body and interior are in very good condition. I don’t like bodywork or upholstery, but thrive on the mechanical stuff, so this was ideal for me. No signs of major leaks under the hood. Engine oil looks and smells OK.
I haven’t had any experience with transmissions other than changing mounts and fluids, but I’m excited to dig in.
It’s been a while since I’ve owned a MB, my last was a 2001 E320. Loved the car, but needed something better for midwest winters (went with BMW x-drive)
Super excited to dig in and tap into the throbbing brain that is this group.
2010 GLK350, 2021 Taco, 2019 Lexus GX460, 2009 BMW 335d, BMW 328xi
Not sure. PO said it slipped in 1st gear a few times, then would not move. I suspect the shop that diagnosed the problem felt the fastest and easiest fix was a new transmission, so that’s what they recommended.
The morbid curiosity part has me too. Could be as simple as a torque converter or solenoid, could be catastrophic failure.
Main transmission issues on the 722.9 are the speed sensors on the conductor plate, typically they throw a transmission code (which you need a scan tool to see) and cause the car to go into limp mode where they won't shift out of second gear. There are a couple people that repair the sensors for $200-$300, pulling it out, shipping it off, and reinstalling a straightforward DIY.
2010 GLK350, 2021 Taco, 2019 Lexus GX460, 2009 BMW 335d, BMW 328xi
First course of action is to get it on the lift and dtrain/ drop the pan. It would be killer if new fluid solved the problem. I’ll share some pics and observations.
Scanning equipment is inbound.
Last edited by Sgt Pepper; Mar 20, 2025 at 07:05 PM.
First course of action is to get it on the lift and dtrain/ drop the pan. It would be killer if new fluid solved the problem. I’ll share some pics and observations.
Scanning equipment is inbound.
I would scan it before doing anything else. Can I assume you’re getting a dedicated MB scanning tool or a programmable one with MB software installed? That’ll be needed to read transmission codes.
There is a lot of information on 722.9 transmissions available. It’s an evolutionary upgrade from the 722.6 in your ‘01 E320. Function philosophy is identical - different parts, an extra sensor or two.
Last edited by Odd Piggy; Mar 21, 2025 at 04:14 AM.
2010 GLK350, 2021 Taco, 2019 Lexus GX460, 2009 BMW 335d, BMW 328xi
I ordered a Launch X431 Creader Elite 2.0 BBA scanner. That’s a really long name for a scanner….
I was looking for a reason to upgrade my Foxwell BMW scanner, so this kills 2 birds with 1 stone.
I’ll share the scan results sometime next week. I’m on vacay in Mexico for a few more days.
While you're under the car, also inspect the front driveshaft that goes out from the transfer case to the front axle. It'll be on the passenger side. The U-joint where it bolts to the front axle is a known failure point and can damage a bunch of stuff in the surrounding area if it fails while underway. A replacement, if needed, is about $130 and a PITA.
I ordered a Launch X431 Creader Elite 2.0 BBA scanner. That’s a really long name for a scanner….
I was looking for a reason to upgrade my Foxwell BMW scanner, so this kills 2 birds with 1 stone.
I’ll share the scan results sometime next week. I’m on vacay in Mexico for a few more days.
2010 GLK350, 2021 Taco, 2019 Lexus GX460, 2009 BMW 335d, BMW 328xi
Originally Posted by andreigbs
While you're under the car, also inspect the front driveshaft that goes out from the transfer case to the front axle. It'll be on the passenger side. The U-joint where it bolts to the front axle is a known failure point and can damage a bunch of stuff in the surrounding area if it fails while underway. A replacement, if needed, is about $130 and a PITA.
I appreciate the driveshaft callout. I’ll definitely check the driveshaft, linkages, and all the moving bits.
While you're under the car, also inspect the front driveshaft that goes out from the transfer case to the front axle. It'll be on the passenger side. The U-joint where it bolts to the front axle is a known failure point and can damage a bunch of stuff in the surrounding area if it fails while underway. A replacement, if needed, is about $130 and a PITA.
My drive shaft failed at 130k miles. Damaged all the sensors and dented my catalytic convertor. Then the transfer case went. All fixed but the cat. Engine light is on but drives fine.
My drive shaft failed at 130k miles. Damaged all the sensors and dented my catalytic convertor. Then the transfer case went. All fixed but the cat. Engine light is on but drives fine.
That is not good, did it have anything to do with the subframe?
Subframe isn't at all involved in a front propshaft failure. My propshaft* took out both O2 sensors on the right cat, and dented the cat's body, but with new sensors it has no issues at all.
*this happened while it was owned by the person I bought it from, and is the reason I was able to buy my GLK for about 30% of what it would have sold for if the front propshaft / transfer case weren't messed up.
Subframe isn't at all involved in a front propshaft failure. My propshaft* took out both O2 sensors on the right cat, and dented the cat's body, but with new sensors it has no issues at all.
*this happened while it was owned by the person I bought it from, and is the reason I was able to buy my GLK for about 30% of what it would have sold for if the front propshaft / transfer case weren't messed up.
Actually, the failure was to my benefit, since I was able to buy really, really nice one-owner, otherwise well-maintained vehicle for chump change, and fix it for under $1,000. In the process, I created what appears to be the definitive videos on repairing the GLK 4Matic transfer case failures. Learned more than I ever wanted to know about that subject, but it seems to have helped a lot of other wrench-twisters avoid dropping $10K or more to replace the entire transmission (the defacto quote at nearly any dealership or indy shop).
Actually, the failure was to my benefit, since I was able to buy really, really nice one-owner, otherwise well-maintained vehicle for chump change, and fix it for under $1,000. In the process, I created what appears to be the definitive videos on repairing the GLK 4Matic transfer case failures. Learned more than I ever wanted to know about that subject, but it seems to have helped a lot of other wrench-twisters avoid dropping $10K or more to replace the entire transmission (the defacto quote at nearly any dealership or indy shop).
I see that is a happy ending then. Thanks again for the heads up.
2010 GLK350, 2021 Taco, 2019 Lexus GX460, 2009 BMW 335d, BMW 328xi
Amazon delivered the scanner this afternoon, and I did some scanning. Not getting any transmission-related faults, but not getting any movement.
In the transmission testing I was able to do, I was not able to get the torque converter to lock. The scanner indicated it was open. I went through the torque converter lock testing instructions, which involved putting into gear and increasing rpm.
No funny or odd sounds or vibrations coming from the transmission area.
When I put it into drive or reverse, the engine rpm drops slightly, like I would expect when putting a car into gear.
I did not get it onto the lift to verify fluid level.
Can’t say with absolute certainty the torque converter is the problem, since I did not confirm fluid level or health, but so far testing is pointing this way.
The torque converter lock sounds like a rabbit trail. The "lock" is just a clutch that takes the fluid drive out of the system for fuel economy. If the TC doesn't lock, the car should still drive 100% fine other than not finding that extra few MPG at highway speed...
2010 GLK350, 2021 Taco, 2019 Lexus GX460, 2009 BMW 335d, BMW 328xi
Originally Posted by habbyguy
The torque converter lock sounds like a rabbit trail. The "lock" is just a clutch that takes the fluid drive out of the system for fuel economy. If the TC doesn't lock, the car should still drive 100% fine other than not finding that extra few MPG at highway speed...
Agreed, and I’m sure things will become a bit more clear when the transmission pan is dropped. The likelihood of the torque converter being the sole reason is slim. I planned on replacing it anyways.
2010 GLK350, 2021 Taco, 2019 Lexus GX460, 2009 BMW 335d, BMW 328xi
Originally Posted by John CC
Can your scanner monitor torque converter slippage, or input and output shaft speeds?
If you were able to lock the converter clutch while standing still the engine would stall.
scanner measures engine torque. I don’t believe it does shaft speeds. Idling in park it measure around 15. A quick blast on the throttle goes up to around 250. In gear, throttle is limited in that scanner feature (torque lock settings/testing) Torque goes from 15 to around 50 at just under 2000rpm, then it idles back down. Throttle response is also limited in this testing.
2010 GLK350, 2021 Taco, 2019 Lexus GX460, 2009 BMW 335d, BMW 328xi
Dropped the pan…the plot thickens
I finally got my son’s BMW off the lift and got the GLK in the air and drained the transmission fluid. Surprisingly not bad looking or smelling. Definitely a brownish tint, but does not smell burnt or otherwise bad. No visible metallic shavings, or glimmer. Next step was dropping the pan. Messy job to say the least. I wasn’t sure what to expect, but it was definitely not this. 3 aluminum bolts with torx heads. 1 is sheared off, the other 2 appear complete. Bolts are around 1” long.
Lots of absorbent on the floor. As I sit with a beer and wait for the mess to clean itself up, I wonder what other surprises await.
Any ideas on the bolts? I would completely understand one or two 10mm sockets in there, but not bolts.
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