To all,

I had this going on another thread, but I had it suggested to me by a sage forum member to start a new thread. Bottom line is that, last week I was driving to Costco and everything was fine. Coming back, the transmission refused to shift into 3rd or 4th gear. I was driving along I-270 at 40mph at 4000 RPM. Not good. Pulled over and checked the fluid. It was a little low and I topped it off, but no joy.
I spent a fair amount of time chasing down vacuum leaks and adjusting the bowden cable, to no avail. Based on advice in the other thread, I capped off the offending vacuum lines (to the EGR and air recirc valve), disconnected the kickdown switch to see if that was causing the problem, and finally put some Trans-X in it since it seemed I was heading to rebuild time. Minimal effect.
My questions -

1) Vacuum - When I hook the Mity-Vac up in the lines, the vacuum will go up to 15, but it goes up pretty slowly. Quite a bit slower than if I stick the 'T' right at the vacuum pump. Should the vacuum increase go fast up to 15 and the slowness indicate something else going on?
2) Do I need to unplug the kickback solenoid on the transmission to completely disengage the kickback circuit? I unplugged the switch under the foot pedal, but don't know if that's sufficient.

Any other ideas welcome since I haven't found the detailed tuning information on this transmission like we have for the 82 model. Thanks for any help!

- Ted

__________________
1987 300SDL 265,000 mi.
1982 300SD 325,000 mi. (and holding)
1956 Packard Clipper 150,000 mi.

I thought I'd give an update here on the transmission. I put the Trans-X in the transmission and thought that things were marginally better. I ended up letting the car sit for 5-6 days, and the car seemed to shift much better for the first few miles, then back to what it was before.

I decided to pull the pan off and replace fluid/filter before doing anything else. The PO had told me he had kept things up to snuff, so I hadn't changed this as soon as I bought. The cold winter temps helped me to decide that, too.

Anyway, the fluid was ugly and there was a lot of dust in there. I'm not sure if it was something the Trans-X helped with or not, but it was there on the bottom of the pan. Cleaned the pan, put new fluid in and the car shifted fine. I couldn't get the torque converter done since I was by myself and got tired of trying to turn the engine over to get the bolt in place.

I'm going to do another fluid/filter change, along with the torque converter, this weekend. I hope this will keep me from putting in a rebuild. (He says, with fingers and toes crossed...)

- Ted

__________________
1987 300SDL 265,000 mi.
1982 300SD 325,000 mi. (and holding)
1956 Packard Clipper 150,000 mi.

Dear tstarr:

Your PO must be a good liar. He told you he had kept things up to snuff so that you bought his car, and that serves his purpose well I believe.

Well try to drain the torque converter and the AT pan again and put in new Dexron III in it.

Good Luck,

Eric

Eric,

The good news on the car is that if this is the worst that happens, I still got a great deal. The car was actually priced assuming a transmission rebuild, since it was shifting really hard (a problem fixed with a few inches of vacuum hose). The ironic thing is that I would normally just do this right away, along with changing hoses, etc., but I bought the car in January, it was about 20 degrees outside, and I did not have access to the garage for the work.

The torque converter drain and new filter/fluid is on this weekend's agenda. So far, so good...

- Ted

__________________
1987 300SDL 265,000 mi.
1982 300SD 325,000 mi. (and holding)
1956 Packard Clipper 150,000 mi.

You may want to consider using a synthetic ATF this time around. It did wonders for my 1982 300D that was experiencing a 3-4 shifting problem when cold. Since changing to synthetic the problem cleared immediately. I think the synth has better cleaning properties and is probably a little slicker and flows better, especially at cold temperatures.

The only thing I could find locally was Quaker State 4x4 Synthetic, which seems to be good. I understand Mobile has a synthetic ATF but I have not found it around here yet.

To me, not shifting properly could easily be a dirt / varnish / crud buildup in the valve body that a good fluid can help clean out.

Transmission fluid change maintenance seems to be very critical for the vintage MBs.

Also, what I do for the torque convertor drain is turn the engine (clockwise only viewed from the front) enough to get close, and then use a large screwdriver to gently coax the drain into position. Almost impossible to get it into position by just turning over the engine.

Ken300D

__________________
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1982 300D at 351K miles
1984 300SD at 217K miles
1987 300D at 370K miles

I'm actually using Amsoil ATF right now, although I should have thought it through more, since it's pretty expensive for running in the transmission for just a few weeks. Mobil-1 ATF is available here lots of places, so I'll probably switch to that in all my cars. I'm a bit surprised, but in a good way, that the problem could be resolved with a simple fluid/filter change. But that's OK by me!

And I have a new appreciation for all of my cars with maintaining more regular transmission service. The last time my wife took the minivan in, they did a transmission "flush". I'm going to be dropping the pan on that one and replacing the filter/fluid as well.

- Ted

__________________
1987 300SDL 265,000 mi.
1982 300SD 325,000 mi. (and holding)
1956 Packard Clipper 150,000 mi.