560SEL trans slips when hot
 

Hello all, just recently obtained a 1989 560SEL with 120K miles on it. Has a few problems but this one has me concerned. When cold, the transmission works fine. When hot, it slips while in drive like it's freewheeling. You give it a few seconds and shift into 3rd and it goes again. Also when you put it into reverse (hot) the car lurches and doesn't back up smoothly. The transmission oil looks to be a little high on the stick when hot but the car wasn't completely level so that might have been a false reading. The previous owner was a typical B/S artist so anything he said has to be taken with a grain of salt. The other issue is the A/C doesn't work. The previous owner claims it has a small leak and just charging the system is good for the summer. Which probably means the compressor is seized solid :mad:
Takes about 4 miles before the trans acts up. Thanks for any help on this issue.

Sorry for your problems,

The lurching of reverse is the inside lip seal. It is hard as nails because of the heat, and eventually it will tear, and you will loose reverse completely. I have been there once, and I'm there with my SL320 with the same problem right now..It is a Under ten dollar seal right behind front oil pump..Photo 7-the inside one.

722.5 transmission oil pump rebuid DIY - Mercedes-Benz Forum

It is the same thing with the forward gear too. A hard o-ring too. The B2 piston inside seal is rock hard. This one you can get to it from the outside, but you may have to remove the transmission mount and use a jack to lower the rear of the transmission down a bit to push in B2 cover with your thumbs to pull out the locking ring..Look at the 15th picture in the bore-the black seal-replace the steel guide with the updated plastic one. I would change B2 piston too as the shaft is probably all wavy..

How to Replace Your Oil Cooler Lines

Basically, with these hard seals. I would bet you need other seals too, and your transmission is very overheated because of the large car.. These transmissions do need a separate cooler for these big cars.

Not what you want to hear, but I like repairing transmissions, and can be done by anyone who DIY's here..

Martin

I wish you were closer, I would drive it to your house :P
In my old age laying under a car seems to mess up my inner ear which affects my balance. I'm ok as long as I'm under the car but when I get up I can't walk straight for a couple of hours. If I had a car lift so I could stand up under it, that would work but not in the cards. I may have somebody that will do it cheaper than usual (special buddy discount). He's supposed to look at it tomorrow. Anything I should tell him regarding parts replacement? Meaning while it's apart be sure to replace this, this and that.:D Thanks for the help, that was very specific. One other odd thing I noticed when I drove it today. When it's hot, in reverse, something in the rear of the car is making noise, tinny sounding. Any ideas on that one?

One other weird thing I noticed: The SRS light in the dash comes on intermittently while driving, stays lit for a second or two, then goes out. Something I should be concerned with?

Doc,

Everyone else PM's me about coming by. It happens all day. A few shops call me. Transmissions are not hard, but you need to have checks and balances. Though I am guessing you have 722.3, but you can confirm your model by going to the dealer, and getting a data card print-out, or sign-up for EPC, and get the data your self, and part numbers.

EPC-net Online

Or go under the car, and check the rim on the transmission where the oil pan butt's-up is the model number, Part number, and serial number.

Here is a thread of a person I'm helping in Australia, and look at all the links and literature.

1996 S280 Australia transmission no reverse diagnose & rebuild. - Mercedes-Benz Forum

Too bad you cannot play under the car. I'm still a young-buck, so I can crawl around...

I like the aftermarket rebuild kits as one gets parts to the valve body. Aftermarket kit goes for about $200 and a rebuilt torque converter from CVC is under $200. I would replace the B2 piston.Get the plastic insert to the B2, and the other plastic parts. Always Replace the copper bearing sleeves. I have been using the rebuild kits from ********. They are made in the USA. If you decide to throw in the towel, Sun Valley transmission is very good, they are about $2k-2year unlimited mileage.

rebuilt remanufactured mercedes benz automatic transmissions

The tinny sound has a similar sound as one is going up hill on a roller coaster.. The reverse seal is no longer sealing The the clutch pack responsible for locking reverse is hitting the drum, and the drum is getting scratched.See the second picture on post 15. The shiny marks on the spline is the result of the clutch pack hitting-that is where the sound is coming from.

no reverse / jerks in reverse when cold - Mercedes-Benz Forum

Hope it helps,

Martin

Could not tell you what is going on with SRS. Maybe a seatbelt switch, clock-spring, airbag, airbag sensor. Maybe you need to read the codes. I do not know these older cars.

Martin

The transmission fairy dropped this off in my driveway last night. It came from a local junkyard. I hope it's the right one for a '89 560SEL. He said he paid $500 for it and it had a one year guarantee. Since he's paying for the whole deal I figure I can't go wrong. He also found some guy to come put it in, working on my driveway. I hope that's not a bad idea, he says he's going to put down tarps to keep the oil off.
Is it worth keeping the old trans? I figure I can do a rebuild on it over the winter when the motorcycle biz is dead around here. Any weird special tools required to take one apart? Never worked on an automatic trans since motorcycles don't have them (except for a few oddballs).

I would at lease replace the B2 bore seal-The round plate with the two orange dots on the plate...the black seal, and swap out the metal sleeve for the plastic one...

How to Replace Your Oil Cooler Lines

Martin

The only problem is I can't get one in time, the guy is coming over tomorrow to do the swap :(
How much do you think it would cost in parts to rebuild my old trans?

Rebuild kit is under $200 with all seals and clutches.

I recommend a new torque converter, that's under $200 .

I would replace the B2 piston that is $140 or so..

Misc Mercedes parts and fluid under $150

Blood / sweat / tears, free as always...maybe pay your self a penny a hour?

Martin