Automatic slipping/flaring

[Cowichan]

It drives fine for a while and then will start to slip or flare.
If I stop the car it generally settles down for a while.
A shop I talked to said that SL transmissions were different
than SE ones. Is that right? I'm going to get the model
number off it on the weekend. It has had the fluid and
filter changed with no effect. There aren't any leaks.
It is a 250SL with a 280SE engine and unknown transmission
model.
Thanks for all comments!

[ja17]

Hello,

Some of the earliest 280SE, 250SE sedan transmissions and some of the finback transmissions were the same. First of all look for the sixteen bolt transmission oil pan for the correct one. (The wrong trans will have four bolt oil pans) Next check the ID plate on the side/bottom of the trans. Sometimes the ID tags on a sedan transmission will actually be labled "230SL" from the factory or the ID label on a 280SL trans may be labeled 280SE from the factory!  No four cylinder or eight cylinder Mercedes  sedan auto transmissions are correct for the W113 SLs. Your best bet is a 1962 to 1967 Mercedes six cylinder sedan, coupe or convertible for the correct transmission. These include some of the W111 (220Sb, SE, 230Sb) , W108 (250S, SE,280S, SE) , W110 (230), chassis models.

Sometimes the bolts holding the valve body in the trans become loose over the years and cause an internal hydraulic leak at its gasket, especially after the fluid is warmed. I always re-torque the valve body bolts during a fluid and filter change. Occassionally it fixes this type of problem.  A long shot, but may be worth a try.

Joe Alexander
Blacklick, Ohio

[paulr]

there is a three position mechanical solenoid on top of the gearbox that can intermittantly sieze. It makes it feel like the clutch is slipping and leads you in all sorts of other directions looking for the cause. Check this as mine ended up seizing completely leaving me with no forward gears and the fear that I had ruined the clutch. An hours job and all is well.

paulr
lovely 1970 280 SL

[ja17]

Good advice from paulr!

Joe Alexander
Blacklick, Ohio

[gary ensor]

The switch at the throttle body which operates the solenoid on the transmission to reduce pressure for gear engagement at idle position can cause the trans to slip or flare if it is sticking. I had a car come to the shop that had the trans replaced at another shop for a slipping condition, but still had the same problem after installing the replacement trans. After inspecting all trans controls we found the switch at the throttle housing defective, replaced it, trans solenoid worked properly

gary ensor

[vanblitter]

69 sl, trans rebuilt in 03 7000k on rebuilt trans. I have slippage when car is cold. I would like a part number # for the switch at the throttle body which operates the solenoid so I can order. please help john

[ja17]

Hello vanblitter,

try checking the switch with a meter or test light first!  Often times it just needs adjusted or the linkage set up.

Joe Alexander
Blacklick, Ohio