500e transmission will not upshift
 

Hi - I headed out the driveway to work the other day (cold start) and headed down the road to find that the transmission would not upshift out of 2nd. Drove back home and parked it. Hoping the problem would magically disappear, I drove it again two days later, still stuck. This upshift problem happened suddenly without any other previous transmission noise, problem, or anything.

I read the codes today. Code 17 came up indicating O2 sensor short - could this possibly be related? I believe the car is starting in 2nd, I tried to force 1st gear start and seemed to start in same gear (now I'm not sure if its starting in 1st or 2nd). Not upshifting at all. Vacuum lines appear intact but I need to check vacuum. Bowden cable seems a little slack at idle although the marks line up at the throttle linkage.... Is there a kickdown solenoid that coule be stuck? I removed the wire from what I believe is the upshift delay solenoid on the back passenger side of the transmission and no change. Any thoughts?
I will drain and remove pan/filter next to see if theres any debris....

BTW - this is a '92 500e. Transmission was rebuilt (by Laurent de Give & Co - Atlanta) by previous owner at 110k mi, car now has 145k mi.

That's surprising that one of Laurent's cars would have trouble!

That aside, it Sounds like you have something stuck in the valve body not allowing the car to up shift (had the Same problem in a 300CD, basically the same transmission).

You could try pulling the electrical connections to the transmission itself..just in case something up stream is malfunctioning. There should be one on the pass rear and another on the drivers side..just don't pull the one just aft of the mod valve (neutral safety switch).

How much time has gone by since the trans was installed?

You might try calling Laurent this week..I'd be surprised were he not willing to help.

Jonathan

do you know how to adjust the cable link to the throttle, that is the first spot to chack then the vacume regulator located on the left side of the transmission, you'll need a pressure guage, if that don't work then you will need to check the valve body do these steps in order to save any unnecessary expense

The transmission was rebuilt/installed exactly 5 years ago. Has worked fine, sometimes upshift delay seemed to hold excessively (upwards of 5k rpm), but always did upshift eventually. I'll pull electrical connections (as I said, I did pull the one on the back of the trans (pass. side) with no change). Thanks for the reply, I'll try calling Laurent this week. I'm in NY so I can't bring it in...

cool - thanks for the guidance. I'll check these things today.

I checked cable and tested vacuum, both seemed fine so I pulled the pan. I found two small pieces of friction material in pan (larger of two was about 1 cm long, triangular). Looks like band (not disc) material based on curvature. Fluid was clear and clean otherwise. Could this be schrapnel from rebuild? Is there any way to inspect bands/discs without transmission removal?

Search this forum for no upshift and govenor. Sounds like your govenor drive gear is broken.

either the valve body has died[rebuilt exchange available thru dealer] or the little screen in the small valve body that filters oil to the govenor is blocked.

I pulled off the valve body today. I haven't disassembled it. Is there anything specific I should look for and check? Things seem very clean and the pistons that can be pushed are unobstructed and move freely. I have a transmission manual arriving tomorrow and hopefully that will guide further disassembly.

Can you tell me how to check the screen on the smaller valve body - the one that filters the govenor? If its okay with you (david s poole) I will call you.
Thanks,
Keith McManus

I pulled off the lower valve body and definitly found some gunk in the cavity below one of the screens. Is a little bit of dirt enough to cause no upshift? The govenor drive gear is visible and looks fine - the gear is metal on this car, not plastic.

BTW - this is an AMG 1st gear start valve body, hence the confusion as to whether I was starting in 1st or 2nd (I didn't know it had the modified valve body until I took it apart).

I will check the 1-2 command valve in the valve body to make sure its not worn and hanging. Apart from that I'm tempted to put it back together and see if it shifts.

Can governor action be checked without dropping transmission and removing access cover?

Thanks for the help and suggestions.

P.S. can someone explain to me what the sliding mechanism is for in a Meyle transmission filter?

Try this, ignition on passenger door open press the gas pedal to the floor, you should hear a click in the rear of the car, if not the kick down switch under the gas pedal is stuck, push the switch down with you hand if it doesn’t click its stuck, then disconnect the wire plug from the switch and drive the car.

Plastic gears are only used on 722.4 transmissions, governor pressure can only be checked with the engine running and the valve body installed. you should have check this frist.

Check the Kickdown Switch!
 

In scanning this thread, I was hoping someone would suggest that kickdown switch before he tore things too far apart! Much more common than tranny problems!

Spook

FYI: I did check the kickdown switch before I started taking things apart on the transmission. With kickdown solenoid disconnected, same symptom.

erase the fault code and reread, then if the same code comes out no choice, you've got to change it and make sure your throttle cable slacks are right and the vacuum pressure is measured according to specs. the shifting is done thru the vacuum and the cable working towards the throttle actuator line.