SL500 (R230) gearshift playing up.

[russell_i_brown]

My 70K mile 2003 SL500 (R230) is having severe problems with gear
selection and I'd be grateful for any pointers or suggestions.

I first noticed this a couple of weeks back. I was in stop/start
traffic in a city centre when pulling away from a set of traffic lights
the car didn't shift into second gear as I expected (the lever and
display was in 'D' and I was only gently pressing the loud pedal) until
the revs got to about 5,500 RPM.

I stopped, left the car for a while and when I restarted everything was
back to normal.

Today, driving south from Glasgow along the entire length of the M6 the
gear selection again started playing up. It didn't change up in the
first three gears until it was revving over 5,500 RPM and even then
tended to stay in third gear (the display was showing 'D').

Prodding of the gear lever to the right, sometimes persuaded the gearbox
to select fourth but it would often jump back to third and refuse to
shift up for a while. I couldn't get it into fifth at all which meant I
ran most of the way at 3,000 RPM (80mph).

Using the 'manual' gear selection from a standing start it goes as far
as fourth (although 3rd to 4th doesn't always work and the display ends
up showing 'D' with the car still in 3rd gear) but I still can't get
5th.

There's no sign of ATF leakage on the garage floor and no warning lights
or malfunctions being shown on the display.

Any ideas what could cause this?

I'm sure if I take it to a Main Dealer they'll just tell me I need a new
gearbox, which would probably be more that the car is worth, and I don't
have a local Indy who's up to much (Cambs, Northants, Lincs border if
anyone's got any suggestions).

TIA.

 

[BlackC55]

Firstly you need to get the codes read in the box as well as a level check of the atf.

My guess is going to be a speed sensor inside the box. It's about a 2hr job to do.