W126 Won't use first gear!

Sep 21, 2005 7 Replies

Hi all, Im wondering if anybody out there knows a little about the transmissions in these cars... I have an '85 500sel, and basically I cannot get it to use first gear... I know that either from a standing start you should be able to floor it past the kickdown switch to engage first or shift to B to engage first, but neither work. I have doubts as to whether my kickdown switch works as there was alot of water in the footwells of the car when I got it, but surely B would still engage it. The fluid level and condition is good, I have also tried adjusting the sliding throttle linkage to the gearbox to no avail. The transmission works fine other than this, ie it shifts smooth, no slipping etc.



Any help will be greatly appreciated!



Ben.



You should know if first gear works at all, even manually; here's the test:

At a FULL STOP shift to L and start off. The box should then be in 1st gear. Upshift to S and immediately back to L for 2nd gear, then up to S for 3rd and D for 4th gear.

If this sequence is confirmed the next step is to find why the transmission doesn't engage first gear as you want. I'd first suspect that the kick down switch under the accelerator is defective and ought to be replaced. The next possibility is the 1st gear servo in the box.

I dont actually have S or L settings on the selector, it goes D, 3, 2 then shift to the right for B. In my manual it states that if you shift to B (Braking) first gear should select at speeds below 25 mph when slowing down, and up to 40mph in acceleration. Do you think that the kickdown switch forms part of the 'B' electrical circuit?

If you have a W/S switch, set it to 'S'

Jan

Hi,

I have tried the starting off in 2 (L) and that only starts in second... I also dont have a W/S switch. I'll have to change over the kickdown switch this weekend to see if that has any effect.

Thanks, Ben.

It's just a switch, so you could test it with a multitester and not blindly throw parts at your problem...

Marty

Hi, I Have a whole 'spare' w126 500sel, so changing out the kickdown switch wasnt a big deal.... The problem is still there though. I got under the car to check the electrical connection to the transmission, gave it a good clean and the problem still remained. Does anybody know what the pinout on the connector are?

Thanks, Ben.

Ok, I may have just answered my own question.... after a bit of google I found that I have a kickdown relay which is a common fault on these cars... so tomorrow i'll pay another visit to my parts car and change out the relay to see if things work then! Heres hoping.

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