Beefing up a stock 722.6 tranny. - PeachParts Mercedes-Benz Forum

Turbo E320 · #1 09-02-2009, 11:55 PM

Besides a PCS controller are there any mechanical things I can do to increase the shift firmness and speed? Kleemann told me I would need to increase the line pressure. I have no idea what that means

. I'm a turbo guy not a transmission guy but I feel I soon will be! I have no problem tearing the thing apart, just need to know what the hell to do!

I got a good 722.6 my buddy and local Mercedes tech swears he took out of a V6 E320 wagon but it has the m104 I6 bolt pattern. I think it came out of a S320 but we may never know

. Long story short it bolts up to a m104 and I'm using it.

Back to the topic though! Shifting needs to be hard as hell and as fast as triple greased baby ****.

The E320 is running 11-15psi right now with no water injection and making the already broken transmission start to slip right after gear changes. It used to only slip when actually changing gears at WOT.

whipplem104 · #2 09-03-2009, 12:08 AM

There are a couple things that can beef up torque capabilities. The easiest is to install the solenoid valves from the slr into the valve body. They are larger and will increase pressure to the clutches. There are also upgraded valve bodies from southern hotrod or IPT. I would go with southern hotrod as they are more customer friendly. Also you can add clutches to the clutch packs to increase load capabilities. The transmission can handle more power but you need more clutches and more pressure.

Turbo E320 · #3 09-03-2009, 12:46 AM

How many extra clutches can one add to the 722.6?

suginami · #4 09-03-2009, 01:11 AM

I don't get the need to beef up the 722.6 transmission.

It is used on the W210 and W211 AMG cars, as well as the Mercedes McLaren SLR.

I think it can handle as much hp and torque as you can throw at it.

Turbo E320 · #5 09-03-2009, 01:13 AM

Well considering mine couldn't handle it, I think it needs a little beefing up lol. They aren't all built the same. Different number of clutches, different solenoids, different TCU programs, there's a lot of differences from model to model.

whipplem104 · #6 09-03-2009, 09:29 AM

IT depends on several things. There are different thickness snap rings to adjust
free play that can give more room but mainly the groove for the snap ring is machined differently for different amounts of clutches. You can either buy new clutch carriers or have a machine shop change the groove. I would locate a cheap used transmission from a v8 car or v12 and use the clutch and piston assemblies with your gear sets to build a fairly decent transmission. Install the other solenoids also. Or you could have a trans built by one of the companies I listed before.

Turbo E320 · #7 09-03-2009, 10:04 AM

I was always under the impression that the v8 and v12 722.6's had different ratios. So could I just swap the V8 or V12 gear set and valve body with the solenoids and call it a day?

whipplem104 · #8 09-03-2009, 10:43 PM

No, what you can do is use the piston and clutch assemblies from the larger transmission and use your gear sets and shafts. The ratios are different but the pieces that the clutch packs go into are not all that different other than the groove were the snap ring goes. I mix and match parts all the time.

Turbo E320 · #9 09-04-2009, 10:26 AM

Ok I'm getting an SL600 transmission from the local salvage yard. I knew the owner of the SL600 so I know it's still good. So can I do what you said with the pistons and clutches and swap the valve body over?

whipplem104 · #10 09-05-2009, 10:22 AM

What you will have to do is split the case in half. The main case has a piston and clutch pack assembly bolted in the rear of the case. You can use the entire case from the v12 transmission. Then you can remove the gear sets from the both transmissions and remove the piston assemblies from the front covers and swap them. I think that the clutch packs on the gear sets have the same number of clutches. So what I would do is install your gear set back in and put the v12 case on the m104 bellhousing with the new clutch packs on it. As far as valve bodies go I would use your original one. Any parts that have gears on them will have to stay with your gear set as all gears will be cut differently. But mostly the number of clutches that are added are in the rear two clutch packs and a couple in the front.
Good luck.

jhodg5ck · #11 09-05-2009, 08:30 PM

If you want tougher clutches and/or kevlar bands let me know

Jonathan

Roncallo · #12 09-05-2009, 11:34 PM

I think I really like the 722.6, but it sure seems to call a meeting and have a board of directors vote before it decides to down shift. I did see a modified valve body somewhere for about $700. It appears that since these transmissions made it into the Chrysler muscle car lineup there are a few people doing stuff with them which is very cool.