m4ff3w SuperDork
Aug. 1, 2011 9:19 a.m.

We test drove and bought an '87 300TE this weekend. The car drove fine on the test drive and about 10 miles after that. Then it started downshifting on it's own into 3rd or 2nd and seemed to get stuck in the lower gear once it did it.

After driving the 25 miles home at 45mph we made it home.

I then took it for a drive and if I was easy on the throttle it would shift ok for awhile - maybe 10 minutes before it started acting up again. Occasionally putting it in Neutral and then back down into D would get it to go into 3rd or 4th, but not always and not for long.

This car has a MBz 722.3 transmission.

I checked and disconnected the kickdown switch, thinking it was stuck but that didn't help.

It seems like it could be a governor issue, as I've read they are prone to having a plastic gear break - but I'm uncertain if that would cause intermittent issues like this.

Any ideas? The trans fluid doesn't smell burnt at all.

Tom Heath Web Manager
Aug. 1, 2011 9:36 a.m.

I'd hit benzworld.org for an expert's opinion. It doesn't sound like the governor problems I'd read about there, but it's been a while.

m4ff3w SuperDork
Aug. 1, 2011 10:17 a.m.

I did just that Tom, thanks.

pigeon Dork
Aug. 1, 2011 10:37 a.m.

Nothing useful to add other than I hate it when everything works great on the test drive and then on the way home the car takes a dump!

Chas_H
Chas_H New Reader
Aug. 1, 2011 10:51 a.m.

Does the shifter move left and right to hold the trans in gear? I'm not familiar with your exact model, newer cars will hold in gear by pushing the shifter left or right. There could be an issue with the shifter or its electrical connections.

m4ff3w SuperDork
Aug. 1, 2011 11:05 a.m.
Chas_H wrote: Does the shifter move left and right to hold the trans in gear? I'm not familiar with your exact model, newer cars will hold in gear by pushing the shifter left or right. There could be an issue with the shifter or its electrical connections.

Oops, that was supposed to be '87, I've corrected the initial post.

No, the only electrical component of the transmission is the kickdown solenoid.

m4ff3w SuperDork
Aug. 4, 2011 11:56 a.m.

Draining all fluid (including the torque converter), transmission filter, and renewing all fluid seems to have resolved the issue.

Though, it's hard to say since it drove fine on the initial test drive.

My working theory is that the car was sitting for a number of months and the during the test drive it sucked up what trash had settled in the pan up into the filter, causing low pressure to the governor.

The hydraulic self leveling suspension worked correctly on test drive, but now behaves as the actuator diaphragms have ruptured.

yay me.

m4ff3w SuperDork
Aug. 4, 2011 11:57 a.m.
Tom Heath wrote: I'd hit benzworld.org for an expert's opinion. It doesn't sound like the governor problems I'd read about there, but it's been a while.

Sadly I never got a response at benzworld or peach parts.

chandlerGTi Reader
Aug. 4, 2011 12:33 p.m.

Peach parts is usually much better for technical questions.

Tom Heath Web Manager
Aug. 4, 2011 1:40 p.m.
m4ff3w wrote:
Tom Heath wrote: I'd hit benzworld.org for an expert's opinion. It doesn't sound like the governor problems I'd read about there, but it's been a while.

Sadly I never got a response at benzworld or peach parts.

That's a shame. Benzworld was jumping with activity not too long ago.

I enjoyed my Benz 300TE quite a bit, and sang its praises to anyone who would listen...until it broke. After pricing replacement parts and looking at the err...labor intensive...process of replacing simple underhood components, my enthusiasm cooled.

If I'd had more time/money/space, I would have loved trying a V-8 swap.

carzan HalfDork
Aug. 4, 2011 3:31 p.m.
m4ff3w wrote:
Tom Heath wrote: I'd hit benzworld.org for an expert's opinion. It doesn't sound like the governor problems I'd read about there, but it's been a while.

Sadly I never got a response at benzworld or peach parts.

m4ff3w, you posted in the tech section of Peachparts. That would seem to make sense, but the diesel section gets more traffic and the regulars are knowledgeable. If you explain (and I've seen this done before) that you got no response on the general tech section and just wanted to get as much exposure as possible before giving up, I'll bet somebody will help. Those are good transmissions and it's probably that plastic gear or a sticking valve. Mine's been good so far, so I just don't have a lot of experience...yet.

m4ff3w SuperDork
Aug. 4, 2011 4:00 p.m.
carzan wrote:
m4ff3w wrote:
Tom Heath wrote: I'd hit benzworld.org for an expert's opinion. It doesn't sound like the governor problems I'd read about there, but it's been a while.

Sadly I never got a response at benzworld or peach parts.

m4ff3w, you posted in the tech section of Peachparts. That would seem to make sense, but the diesel section gets more traffic and the regulars are knowledgeable. If you explain (and I've seen this done before) that you got no response on the general tech section and just wanted to get as much exposure as possible before giving up, I'll bet somebody will help. Those are good transmissions and it's probably that plastic gear or a sticking valve. Mine's been good so far, so I just don't have a lot of experience...yet.

Thanks for the tip.

The intermittent nature of it makes me doubt it is the plastic gear, we'll see how it goes with fresh filter and fluid.

Our 190E 2.6 is very similar mechnically and has been a good car in the year we've had it with over 200k on it.

benzbaron Dork
Aug. 8, 2011 1:51 a.m.

I had an issue with the vacuum modulator on my car where it would give me a clunky downshift. I'd would just go for a fluid filter change then drive the crap out of it, run it through the selector to push the oil through the passages then after a 1000 miles or so change the fluid again. Worse comes to worse you are 300$ from a junkyard transmission. I would check the bushings/kickdown/vacuum modulator/tranny mounts and all the BS before replacing the thing.

Good luck and keep us posted!

You'll need to log in to post.

Also on Grassroots Motorsports

You Need This: E39-Chassis BMW M5 for $6000?

5 hours ago in News

Buy one of our favorite Q-ships.

Grassroots Motorsports LIVE! on Wednesday, August 23: Building a Homemade Sim Rig

9 hours ago in News

We’re taking our sim-racing game to another level.

That's What i Like: What Attracts Us to Specific Cars?

10 hours ago in Articles

I just spent 10 days in one of my new favorite cars: the 2017 VW GTE.

Your Projects: Wide-Body, V8-Powered Porsche 944

1 day ago in News

Wing, flares, V8 swap and more!

You Need This: Eclipse!

1 day ago in News

Today's special.

Your Projects: Boosted and Flared E30 BMW

1 day ago in News

Another forum member put it best: “This build is absolutely mental. And I mean that in the best possible way.”

You Need This: 1990 Suzuki Carry 4WD Mini-Truck

1 day ago in News

It looks cool, matches our cargo shorts, and makes little sense.

Concours d’Lemons: Showcasing the Best of the Worst and the Worst of the Best

1 day ago in Articles

This year’s Concours d’Lemons celebrated two cars rarely associated with the glitz and glamor of Monterey.

You Need This: Gullwing Doors and Exotic Styling for Just $1500

1 day ago in News

Meet some brown ’70s awesomeness.

Acura Unveils New Prototype Race Car in Monterey

3 days ago in News

Acura yesterday unveiled the new Acura ARX-05 prototype race car.

OUR SPONSORS

Grassroots Motorsports Magazine

Subscribe Today

Also get your instant access to the digital edition of Grassroots Motorsports Magazine!

Learn More
pHjvnTzEkPJBMKycnx01ufxvtGSVTZLS