500E Transmission at WOT downshifting to 2nd, then 3rd, then 2nd

[smilecenterlab]

Moderator's Edit - this post was cleaved off of this thread - HOW-TO: Transmission Overload Protection Switch Removal | "HOW-TO" Tutorial Articles

@dionphaneuf and I helped @smilecenterlab replace his transmission overload switch as a guess ..... in an attempt to solve the issue that he describes below. However, replacement of this switch does not seem to have improved the result.

Note that before replacing the switch, we observed no relevant codes with the SDS tool (there was the typical GM undervoltage code which we cleared.). Anyways, @smilecenterlab seeks additional input, by way of this thread, on the potential source of this issue.




Car has issues with transmission shifting.if i do a quick accelaration from take off it shifts from 2nd to 3rd then immediately back to 2nd then back to 3rd again.transmission was rebuilt about 5 years ago at shmidt.

 

[Beater400E]

I had something similar with a 92 500SEL I had. In that case it was just low fluid level. I'm sure you've already checked it, but just in case, make sure your fluid level is bang on correct.

 

[gsxr]

Car has issues with transmission shifting.if i do a quick accelaration from take off it shifts from 2nd to 3rd then immediately back to 2nd then back to 3rd again. transmission was rebuilt about 5 years ago at shmidt.

Is the problem only at part throttle?

What happens if you pin the throttle from a dead stop, though the 1-2 and 2-3 upshifts? Are those WOT upshifts normal?

 

[smilecenterlab]

usually it happens when accelarating from dead stop

 

[gsxr]

usually it happens when accelarating from dead stop

Right - but is the acceleration at 1/2 throttle, 3/4 throttle, or full throttle (WOT) where the kickdown switch beneath the accelerator pedal is engaged?

Normal WOT upshifts will look like this:

 

[smilecenterlab]

mostly at 3/4 or full throttle

 

[jftu105]

Check the linkage bushings. There are two of them on the side of the transmission. These two bushings ensure that the shifting linkages have no play. One of my cars had the problems not being able to shift out of 2nd gear. It was due to that I only replaced one bushing, not knowing there is a second bushing. As a result, the shifting linkage caused incorrect positioning in the valve body control. A local MB specialty shop added the second bushing, all problems solved.

Therefore, at least, check the condition of those two linkage bushings to rule this possibility out.

jftu105

 

[smilecenterlab]

thanks,will check on that.