'07 E320 Bluetec- NO FORWARD GEARS - PeachParts Mercedes-Benz Forum

ROLLGUY · #1 04-06-2019, 10:33 PM

My sister-in-law had her '07 E320 Bluetec (formerly owned by myself) towed to my place, with no forward gears. Reverse works fine. It has the 722.9 transmission. I hooked up my scanner, and found 5 transmission related stored codes. They were all CAN communication codes. However, I looked in the live data menu, and it seems that the TCM is receiving the proper signals from the shifter and engine. I suspect it has a hydraulic problem, or a bad solenoid (really just guessing here). The TCM is inside the trans, and is VIN coded, so no backyard swaps for it, dealer only. Anyone know if there is something I can fix, or is a trip to the dealer my only option?

dieselworks · #2 04-07-2019, 03:19 AM

Sounds like a mechanical failure.
My first informed guess is you could have a broken band. Wouldn't show up as a computer fault.
Second guess is a clutch seal is compromised. Not allowing the clutches to have pressure. That too wouldn't show up as a computer fault.
There's a reverse band and if it's ok then you'd have reverse.
Either way the transmission needs to come out. The transmission needs to disassembled.
Could you describe the conditions that led up to not forward. If it happened all the sudden then it's a forward apply band.
If the lack of going forward was gradual process then it's a clutch pack seal. Another clue would be when the car was cold you'd have forward movement but once it warmed up...your not going anywhere.
I haven't rebuild a Mercedes automatic transmission but they all have similar components and related failures.
Roddy

Sent from my SM-G900I using Tapatalk

ROLLGUY · #3 04-07-2019, 09:35 PM

Quote:

Originally Posted by dieselworks

Sounds like a mechanical failure.
My first informed guess is you could have a broken band. Wouldn't show up as a computer fault.
Second guess is a clutch seal is compromised. Not allowing the clutches to have pressure. That too wouldn't show up as a computer fault.
There's a reverse band and if it's ok then you'd have reverse.
Either way the transmission needs to come out. The transmission needs to disassembled.
Could you describe the conditions that led up to not forward. If it happened all the sudden then it's a forward apply band.
If the lack of going forward was gradual process then it's a clutch pack seal. Another clue would be when the car was cold you'd have forward movement but once it warmed up...your not going anywhere.
I haven't rebuild a Mercedes automatic transmission but they all have similar components and related failures.
Roddy

Sent from my SM-G900I using Tapatalk

I was afraid of that. That totally makes sense. I will call Marc at Sun Valley Mercedes Transmissions on Monday, and see what he says.....Rich

pawoSD · #4 04-07-2019, 11:03 PM

How many miles were on that 722.9?

ROLLGUY · #5 04-08-2019, 08:37 AM

Quote:

Originally Posted by pawoSD

How many miles were on that 722.9?

Around 90K

ROLLGUY · #6 06-07-2019, 10:51 PM

I picked up the rebuilt trans from Marc at Sun Valley Mercedes Transmissions the other day. Today I installed it in the car. I made a transmission lift stand from an HF transmission jack and some lumber. It worked great.

Let's back up a bit, to a couple months ago. After talking to Marc, he agreed that it was a mechanical failure, and that I should pull the trans and bring it to him. The problem was mostly a torn Oring on one of the valves, but the clutches were worn out from low pressure. Marc did a complete rebuild, including an upgraded torque converter.

There were no issues installing the trans today, and it only took me about 2 hours to get it in and all bolted up. The time consuming part is pumping in the 10 quarts of fluid, and running the engine till the trans temp is up to 80C. This process took another hour. While I was waiting, I worked on the carpet shampooing on my SL: New to me '85 SL Diesel-repair and renew thread
Marc told me it would shift a little weird for the first few drives, and he was correct. The TCM has to learn the operating habits of the car (adaptation). With Xentry, the adaptation values can be programed in (I think that is how I understand it). Since I don't have that system, and I don't want to drive the car the 100 miles to Marc's shop, just driving it around and then parking with the engine idling for 20 minutes or so helps it learn. A couple times doing this so far has gotten it almost there.

This job seemed a little intimidating for me at first, but it was actually a little easier than I thought. I am now a 722.9 expert!

pawoSD · #7 06-08-2019, 01:10 AM

Nice! Doesn't really look any worse (potentially easier) than the old 722.3's....

engatwork · #8 06-08-2019, 07:16 AM

Interesting that it died at 90k.

oldsinner111 · #9 06-08-2019, 07:42 AM

what did the do wrong with original t. convertor. You said upgraded?

ROLLGUY · #10 06-08-2019, 09:19 AM

Quote:

Originally Posted by pawoSD

Nice! Doesn't really look any worse (potentially easier) than the old 722.3's....

Actually, a later TD with the insulation around the trans tunnel is WAY harder than this W211.

ROLLGUY · #11 06-08-2019, 09:25 AM

Quote:

Originally Posted by oldsinner111

what did the do wrong with original t. convertor. You said upgraded?

Evidently the shaft bushing inside the stock converter wears out prematurely, so Sun Valley has developed a fix that involves cutting of the hub, and welding on a new one that accepts a bronze bushing (or something to that effect). There are other things they do inside the trans that improve it's longevity. Sun Valley Mercedes Transmissions

oldsinner111 · #12 06-08-2019, 09:34 AM

cool,been looking at cdi here,just wondered

tjts1 · #13 06-08-2019, 11:26 AM

Did they reuse your existing conducturplate in the rebuilt transmission?

ROLLGUY · #14 06-08-2019, 11:37 AM

Quote:

Originally Posted by oldsinner111

cool,been looking at cdi here,just wondered

The CDI has the 722.6 5 speed trans, and is even more DIY than the 722.9
The TCM is inside the trans in the 722.9, and is part of the valve body. If either goes bad, the entire unit has to be replaced (with VGS-1). If it is the later VGS -2 or 3, the units can be replaced separately. Replacement of the TCM requires SCN coding. The 722.6 has an easily replaceable conductor plate and associated parts. Short of a mechanical failure or worn out clutches, most everything else is DIY. Marc at Sun Valley suggests changing the fluid and filter at 24,000 mile intervals, and I wholeheartedly concur. Whenever I acquire a W211, a complete trans service is done, and every 24,000 miles thereafter. One of these transmissions will outlast the rest of the car if maintained properly.........Rich

ROLLGUY · #15 06-08-2019, 11:48 AM

Quote:

Originally Posted by tjts1

Did they reuse your existing conducturplate in the rebuilt transmission?

As noted above, the TCM was re-used (VGS-2), so no SCN coding was needed. The Orings on all the solenoids were replaced. MB only sells the valve bodies as a unit, and does not sell the Orings separately. Marc has a source for the Orings, and replaces them without the need to replace the entire valve body. Each time I drove the car yesterday and today, the shift quality and timing improved. After driving the car for a few miles, I let it idle for 20 minutes or so. This gives the TCM time to "download" the information from the main computer in order to "adapt". My drive this morning was very smooth, with the exception of a slight harsh 1-2 shift. I imagine in just a couple more short trips, the trans will smooth out the 1-2 shift, and it will be back to normal.