'87 300d Trans not shifting right - Page 2 - PeachParts Mercedes-Benz Forum

Pete Burton · #16 11-04-2004, 04:06 PM

Quote:

Not that it has anything to do with your problem . . . I also used Trans-X for a couple hundred miles then changed filter and fluid. I switched to Mobil 1 syn as some of the others above wrote. It has now been hundreds of miles since and it never shifted as smoothly as it does now. I also had chased some vacuum gremlins and fixed those.

same experience here. I replaced the B2 into a trans that barely shifted into 4th to start with. It's been gradually getting better for 2 months now.

pmari · #17 11-04-2004, 04:20 PM

I haven't used this product http://www.auto-rx.com/ yet, but it has gotten some good reviews over on http://www.bobistheoilguy.com/
Supposed to be much better than Trans-x and it can be used in the motor also.

Some Trannie stuff.....

http://www.continentalimports.com/ser_ic20242.html

http://www.babcox.com/editorial/ic/ic20242.htm

http://transmission.articles.mbz.org/adjust/

jfikentscher · #18 11-08-2004, 11:53 AM

BrierS,

Please go into the vacuum gremlins you fixed. I have a suspiscion that my problem is vacuum related.

Any help appreciated.

Thanks,

Joe

BrierS · #19 11-08-2004, 07:04 PM

Quote:

Originally Posted by jfikentscher

BrierS,

Please go into the vacuum gremlins you fixed. I have a suspiscion that my problem is vacuum related.

Any help appreciated.

Thanks,

Joe

Joe,
To start with, I had the old style vacuum pump so I ordered the new type from FastLane. Once installed, I followed the forum's advice on what the vacuum should be as you move progressively away from the pump. I also removed the EGR valve, the vacuum lines going under the air cleaner and eliminated the two devices they went to (also under the air cleaner). Those are the vacuum valve transducers. That rendered the five-way (I think) which is located just to the left of the front portion of the valve cover overkill. At first I plugged the unused ports but later replace it with a two-way connector. Those steps took care of some of my vacuum leaks. By the way, contact Brian Carlton and see if he has an EGR replacement (test purposes ONLY) kit left. Many of us bought his kits for test purposes. I test mine every day.

Next were leaks at the Switchover Valve. That is attached to the left fender (actually there are two of them). If you go to the FastLane site and select the year and model of your car you will be able to see a picture of each of these devices if you are not already familiar with them. On some parts I printed the photos and went searching under the hood. Next, I had a major leak where a vacuum line plugs into a rubber receiver low and to the left of the IP. The vacuum line plugs in from the front toward the rear. Ultimately, I used both my vacuum gauge and my Miti-Vac to test each line and connection. There is at least one line that has what I believe they call designed bleed-down. I will look under the hood tomorrow, write down each line color and email you a better description. Before I do, I'll find the postings from the forum members that helped me locate these. If you don't already have a Miti-Vac, get one. They are extremely inexpensive and if taken care of last for years.

psfred · #20 11-08-2004, 07:10 PM

Make sure the kickdown cable is attached and working -- should be all the way out of the housing with just enough spring tension to keep it from rattling with the throttle closed, and run all the way in at full throttle (backwards from usual).

If it won't run back in when you open the throttle, the cable is broken in the housing or loose in the tranny and stuck at the wide open position, won't upshift until you get to redline.

I'd also have the kickdown solenoid checked, it may be stuck or otherwise blocking the internal passage, causing it to act as if you have the accelerator floored all the time.

Peter

BrierS · #21 11-08-2004, 07:13 PM

Read and follow what Peter says. He is one of the ones I have used advice from regularly. In fact, follow this thread and it will give you most everything I started to outline. Don't get discouraged either. Too many people here that can help any of us through any problem we'll encounter.

Vacuum Line Size OD & ID - Please

jfikentscher · #22 11-22-2004, 09:24 AM

Update:
Replaced Vacuum Switch
Replaced Vavvum Modulator
ReplacedVacuum regulator on IP
replaced Kickdown Switch.

After opening the trans, the tech said the valve body accumulator was broken. He repaired w/new spring and reconditioned it?

Charges:
$80.00 - Trans service
$150.00 - Parts
$235.00 - Labor

$440.00 total.

Still shifts a little hard but will take it back for tuning. (included).

Lyons Transmission, Brick, NJ. Dan, was very nice to deal with and seemed to know the vacuum system.

Thanks for all the help from forum members.

Joe

psfred · #23 11-22-2004, 11:13 PM

There are several simple fixes for things that cause a no upshift condition, including that accumulator.

The governor (speed sensor, really) circuit works by increasing pressure in a control circuit proportional to road speed, either by a small pump (or the secondary pump in older trannies) or by a controlled leak operated by set of fly weights. Anything that prevents this speed signal from correctly operating the shift valve(s) will prevent the tranny upshifting.

Some later versions have a plastic drive gear sleeve for the governor, and when it shatters, the tranny refuses to upshift. There is also a check valve that can fail, causing a spring to get in the governor pump gear (which shatters the plastic drive gear). A broken spring or leaking accumulator in the governor circuit or shift valve will cause the same condition.

Niether problem requires a tranny replacement, at worst a valve body, much cheaper than a rebuild.

Peter