SL65 transmission
 

From what I read the 7speed transmission cannot handle the torque of the twin turbo V12. Is the 5speed automatic used in the SL65 the 722.6? I read on here that the 722.6 had a design problem and has some kind of bearing problem which leads to the destruction of the planetary gear. Is this true because it seems this transmission can handle a lot of torque if it is the same one used in the SL65.


On the side note can a 722.6 be built into a performance transmission? Thanks

The SL65 uses the 722.6 transmission, along with all the other Bi-Turbo V-12's, including the Maybach. The AMG V-8 Kompressor line-up, including the SLR, use a variant of the 722.6 as well.

So this transmission physically can handle an enormous amount of torque? I am sure those varients of the 722.6 they use have high performance clutch packs etc. I wonder if that is the only difference between them. I emailed Raybestos blue clutches to see if they make a clutch pack for this transmission. I hope the factory gears, inputshaft etc. themselves can handle 900lbs of torque.

Do all 722.6 share the same bell housing pattern? Meaning can the S500 transmission bolt onto the V12 engine?

I'm pretty damn sure I've read a few times how the SL65's torque is computer limited so that the transmission can handle it. I think it's limited to 1000Nm. Or it would've produced 1000Nm if unlimited (can't remember which statement is correct).

Pentoman, you're right, torque is limited to protect the transmission, I can't remember the figures; I think it is further limited in 1st and 2nd gear.

I understand the 722.6 is basically sound. Early models suffered two problems. First, ATF leaked out of a dodgy 'O' ring into the transmission's ECU which thereupon failed; cured by a revised 'O' ring. Second, tiny metallic fragments generated in the first years of the transmission's life damaged other components; this has been cured by the installation of a magnet in the pan and the inclusion of an ATF change at 40,000miles in the service schedule.

The transmissions have a 2 designations. Thei first is the transmission designation that is easy to find in my case its the 722.621 for the 96 SL600. There is anther designation which I belive can be fould on the side of the transmission, and its something like W5AXXX

W beans it has a torque converter
5 means 5 forward gears
A is a version code
XXX in Max input torque in Nm

John Roncallo

And how much can the sl600/sl500 tranny handle?

Since I have my transmission out I will try to take a look. It is a 96 SL600 which may be different from the SL500.

John Roncallo

OK I looked at my transmission and the only numbers are 722.621. The sales designation I was refering to is described on page 1 of the Mercedes Benz publication "Model Year 1996 Automatic Transmission 722.6 Introduction to Service". Of course in true Mercedes Benz tradition they dont tell you anywher the number can be found. Also the exanmple they give you in the book is W5A580 which means 580 Nm torque rating. My SL600 has 570Nm/3800 RPM = 421 ft-lb. So my guess is that my SL600 trans is W5A580 good for 580 Nm.

Also one place I have seen the W transmission designation used was in Mitchel Automotive Manuals. Where my 560SL transmission was refered to as a W4XXXX.

John Roncallo

OK I found the information in another MB Transmission manual that I forgot I had. Here it is.

722.6 (W5A580) Passenger Cars with 8 and 12 cylinder engines
722.6 (W5A400) AAV vehicles with 8 cylinder engines
722.6 (W5A330) Passenger Cars with 4, 5 and 6 cylinder engines
722.6 (W5A300) AAV vehicles with 6 cylinder engines
722.6 (W5A280) MB Vans

So it appears the king of the hill of the 722.6's was the W5A580 with a capability of 580Nm of torque.

I dont know what trensmissions were available after 1996 and what there capabilites are or do they bolt up to my 96 M120 or M119's

John Roncallo

Thank you this is great information. I am looking for the correct 722.6 to mate to my M120 V12 engine. Are these numbers stamped or casted on the side of the transmission?

What is a AAV vehicle?

722.621 came with my M120, 1996 SL600. There is a machined flat on the side of the transmission with this number on it.

John Roncallo

Nice to be here again.


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Hilda
TA Performance - Buick Performance Parts Catalog by TA Performance

Thank you John,

This info will help prevent me from getting ripped off as I look for a used tranny. I am twin turbo charging my M120 V12 and building a carbon fiber intake manifold (in the process of drawing this up on CAD and using the fluid dynamics simulator) The stock one weighs too much. My plan is to purchase the clutch pack and bands from the Sl65 assuming Mercedes is selling the replacement/rebuild parts for that transmission. This will help it handle the torque increase

SL65 722.649
Same on the Maybachs and S 600's (220, 221), S65