w124 300d transmission issues

[ou2mame]

I have an 87 300d with just under 200k on it. The transmission has always shifted great, nice firm shifts. Never any hint of slippage. I was pulling out of a parking lot and accelerated up to speed, maybe hitting 4k RPM. I'm assuming that under normal operation, my car starts in 2nd gear to explain this now. I stopped at a light soon after pulling out of the lot. When the light turned green I hit the gas and started driving, but when it changed into third gear the engine just revs freely, but it doesn't decelerate as if it's stuck in 2nd gear. The car just coasts, and the engine revs freely when I push the gas pedal down. And when I slow down and it shifts back to 2nd, I can accelerate again. If I put the shifter in 2nd, it decelerates when I let off the gas, but in 3 or D the car will coast after moving into 3rd gear (it feels like anyways). While limping it home in 2nd gear, it did actually shift through all the gears and drove fine once in a while. So does anyone have any idea where I should look first? Fluid level looks fine, and vacuum system appears fine also. All the hoses are there, and the shut off worked when I parked it.

[Sugar Bear]

When was it serviced last? Is it driven regularly or does it sit for extended periods?

[ou2mame]

Originally Posted by Sugar Bear

When was it serviced last? Is it driven regularly or does it sit for extended periods?

I've owned the car for several years and the fluid was bright when when I bought it. The owners had died so I couldn't confirm the service intervals. Judging from the condition of the car I'd assume it had some type of service in its life. I don't drive the car much, but I take it out every month or two.

[Diesel911]

Originally Posted by ou2mame

I've owned the car for several years and the fluid was bright when when I bought it. The owners had died so I couldn't confirm the service intervals. Judging from the condition of the car I'd assume it had some type of service in its life. I don't drive the car much, but I take it out every month or two.

Look at the vacuum line and connectins and see if the transmission modulator cap is still there or if the cap is cracked.

After that the basic place to start is to change the ATF and the filter. As the bands and clutches wear the filter catches some of the particles.

[Sugar Bear]

Agree with change the ATF and filter. Drain both the converter and the pan. Check the condition of the rubber cooler hoses at the radiator and replace as needed. Do not flush the transmission, just do a gravity drain of the pan and converter.

I've had good results with Valvoline MaxLife ATF.

Add a tube of Lubegard additive to the fluid refill.

Drive it more often and push it through all the gears, sitting that much will create problems in many systems of the car.

[ou2mame]

Alright thanks for the advice guys. I'll check the modular cap (I'll have to look up what that is!) and drain the transmission and change the filter. I actually have a filter and planned on doing this, just never got around to doing it.

[ou2mame]

So, I did the transmission fluid and filter.. no change. I drove it around my neighborhood for about 45 minutes. I checked the vacuum hoses and didn't see anything out of place. Anything else I should look at?

[87tdwagen]

Check the state of the bowden cables and linkage. make sure that the slop in the "throttle" linkage between the IP and cable connection does not have any undue slop. The goal would be to adjust the throttle bowden cable adjustment nut, so as soon as the cable moves, the linkage moves, and then adjust the bowden cable on the trans (lower) to match

[ou2mame]

I checked the bowden cable and it appears to be functioning fine. It doesn't have any noticeable slack. Would that even cause the issues I'm experiencing? I put it in drive and move, and it changes gear and coasts, and the engine revs freely. if I put the shifter in 2nd gear, the car decels. It's like I'm just missing the rest of the gears for some reason.

[87tdwagen]

It might be your k2 spring. I believe this controls 3 to 4 and back to 3 shifts. It's been so long since I upgraded mine that I can't recall all of the details.

Read up on the K1 valve/spring and K2 spring upgrades, they are wear items and fairly inexpensive. The are in the valve body, but are accessible from the side of the vb, no need to drop the vb assembly.