560SEL Transmission Slip - PeachParts Mercedes-Benz Forum

patterson · #1 05-23-2006, 11:21 PM

I am having a problem with the transmission in my '91 560SEL.

- I bought the car with what was advertised as a bad transmission. It wouldn't go forward or backward. The transmission made no noise when put in gear.

- I replaced the valve body with on I had from another 560 tranny of unknown condition.

- After replacing the valve body the car had all four gears but it would slip in higher RPM's in 2nd gear.

I replaced the valve body again with another from a known good transmission, and I pulled out the B2 piston to check for some problem there. No improvement.

The car takes off in second gear, as it should. When first taking off the transmission feels firm, will even chirp the tires. As the car climbs to the higher RPM range in second gear it holds it too long and starts to slip. After it shifts into third gear the tranny is perfect in third and fourth.

I have another transmission I will probably swap into it. I was just hoping for an easy solution.

mbdoc · #2 05-24-2006, 09:35 AM

Second gear on that & all 722.3_series transmissions uses BOTH bands..

Third gear uses the main B2 band & K-1 clutch pack.

What happens if you start in 1st by locking the "B" switch on the shifter??

jhodg5ck · #3 05-24-2006, 08:44 PM

just for fun have you tried turning up the modulator pressure?

Jonathan

patterson · #4 05-24-2006, 09:22 PM

I have tried cranking up the modulator pressure and it only makes the other shifts harsher.

I tried putting it in B and it acted exactly the same. I misdiagnosed the problem it seems. When I held it to it I found out that is not actually a slip it is just taking off in first.

I think this would indicate that the B1 band isn't grabbing? Has anyone ever heard of a B1 servo problem? I have had those apart before but I the only thing I remember is that the spring is alot stiffer than the B2.

Thanks for the help.

Matt

C32AMG · #5 05-24-2006, 10:23 PM

The no movement with the original valve body is a stuck B2 valve, if the pan was clean, no Burt smell or excessive metal, just clean the valve body,free the B2 valve and try it.

mbdoc · #6 05-25-2006, 09:02 AM

The original B-1 piston was adjustable..different shims behind the band side guide pin...replacements are "self-adjusting"..suggest you invest in a new self-adjusting B-1 piston & guide to see if that is the problem before the trans comes apart!

patterson · #7 05-25-2006, 10:05 PM

I pulled the B1 piston for a look. The band seems pretty toasted. I will try the adjustable B1 piston before I pull it out, but I am pretty sure that this tranny is going to have to come out eventually.

Thanks for the help