1990 190E 2.6 Transmission Problem

[Zookman]

I recently aquired a 190E 2.6L equipped with an automatic transmission. The car was only driven about 500 miles over the last three years. As it turns out, there was a blown fuse on the OVP relay behind the firewall, which created a very hard starting condition. I think the hard starting problem is the reason the previous owners stopped driving it. Right now, the car is pushing out some white smoke (does not look like a blown head gasket, as the oil is not sludgy and the coolant is not oily) and is not shifting out of low gear. The trans shifts smoothly from park to reverse to neutral and drive, but it just won't shift out of the low drive gear.

As the car has been sitting so long, any initial suggestions. I was planning on replacing the trans filter and fluid and see if the fluid change helps anything, but have a feeling it is probably something else. The trans fluid looks clean, is full and does not smell burnt in any way. I'm leaning towards a bad kickdown solenoid or modulator valve. I don't have a repair manual for the car yet, so am at a bit of a loss for troubleshooting any further. I would like to know what the kickdown solenoid and modulator valve actually do. I have a four post lift in my garage, so I can easily access the transmission to do any inspections or repairs. Any assistance is greatly appreciated. Thanks!!!

 

[Zookman]

Follow-Up

I may have been a bit unclear in my explanation about how the transmission is operating. The gearshift lever moves smoothly from Park - Reverese - Neutral - Drive - 3 - 2. When I place the shifter into Drive, the transmission engages smoothly and the car goes forward, but as I increase my speed, the transmission will not upshift into the higher drive gears. As speed increases, the engine RPMs begin to wind out. I have run it to about 5,000 or 6,000 RPMs and it will not upshift. I have also tried upshifting the transmission from 2 to 3 to Drive and the gearshift itself moves slowly, but have no impact on the shifting of the transmission from a running standpoint.

I was thinking that maybe the kickdown solenoid failed, causing the transmission to remain stuck in the lowest gear when in drive. Any idea of how to check to see if the kickdown solenoid is operational?

The other issue is that the car sat for about 3 years and was only driven about 500 miles during that time. I was thinking about changing the transmission fluid and filter and see if that creates any improvement, but the fluid appears to be very clean, so that might just be a waste of good money.

Any suggestions you might have for testing would be greatly appreciated.

 

[tom7035]

Auto trans - no upshifts.

Hello John. I gleaned the following information from a 'friend of a friend' in the specialist auto transmission business which may be of some assistance to you.

'Failure to upshift can be caused by;
(1) Incorrect governor pressure or a defective governor assembly.
(2) Sticking kickdown solenoid valve OR a constant voltage to the solenoid, caused by a faulty fuel pump relay OR simply a sticking kickdown switch.
(3)Dirt or sticking valves in the valve body.'

You appear possibly to be on the right track at (2) above, hopefully, as the others sound much more complicated/expensive.

Cheers, Tom.

 

[Zookman]

Got another update. I took the car out again for a brief ride and it looks like I was somewhat incorrect about the shifting issue. When I put the car in drive, the RPM's ramp up as I accelerate and the automatic transmission does not upshift. If I drop the shifter from Drive to 3, there is no response by the transmission. However, when I shift from 3 to 2, the car does downshift (I'm assuming to low 1). If I upshift from 2 to 3 or from 2 to D, I can't detect if the transmission is upshifting at all and the RPMs continue to ramp up.

I also disconnected the kickdown solenoid and there was no change in the operation of the transmission. I also inspected the underside of the transmission to see if any hoses/cables/connecters were loose or disconnected, but found nothing. I did disconnect the main plug on the transmission, which just caused a no start condition, so I reconnected it.

Any suggestions about anything else I should inspect. I'm not quite sure of how to adjust (or even access) the governor assembly.

Thanks for any assistance!!!

 

[tom7035]

Hi John.
Looks like it's up to you. I think the governor (vacuum?) can be adjusted externally, left hand side of 'box, but this is specialised stuff and wouldn't recommend trial & error.
Please keep in touch with us with eventual cure, and good luck, Tom.