(I've posted this in the general Tech forum, as well as, the obvious SL Forum just in case someone happens to know something).

My 93 300SL R129 (109k) skips 4th gear as it downshifts up a hill from 5th and just barely shifts into 4th and then into 5th as it accelerates on the freeway.

I did a search in the SL Forum for "4th gear" and found an old post from 2002 about a faulty switch under the center console and a service bulletin about poor contact affecting a control value solenoid (we think it's referring to the switch).


We've bypassed the switch just under the center console, as mentioned as the solution, and the problem persists. The trans has no other issues and is otherwise smooth as silk. It was rebuilt (all the soft parts and one band replaced, no solenoids replaced) by reputable Benz indie a couple of years ago.


Is bypassing the switch a valid test?
Any other feedback as to other tests or possible fix's?



Thanks,


Al

__________________
03 CLK430 Cabrio 211K Pweter Silver/ Oyster Leather
90 300SEL 214k Pearl Black/ Alto Grey/Black Leather

Prior: 85 190E, 88 300TE, 89 300TE, 90 300E 2.6, 90 300TE, 92 300E 2.6, 91 and 93 300SL, 87 Ferrari Mondial Cabrio

If your vehicle has the M104.980 engine with 722.5 gearbox, you need to read and clear faults on the MAS box - you do this with a cheap-to-build led tester with a push-button. There are posts explaining how to build this and it should cost less than 20 Euro.

Search also for 4th 5th issues on 722.5 gearbox - you might find some stuff from me about how to do all this.

I did this and my 4th 5th issues went for good - all is now well after around 2 years.

If it's the later engine the rules may be different.

Bon courage.

RayH