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

jfikentscher · #1 09-21-2004, 04:31 PM

Thought I should start a new thread. Well the '87 won't shift right. At startup it will go in 1'st gear only,. If I rev it up to about 25, shift to neutral and shift again into drive, second gear will engage. but no higher. reverse works, Occasionally it will slip out of first.

Drained some fluid and put Trans-X in. Idled and shifted through the gears from P to D2 but this has not helped yet. Just took the car out for about 5 miles and still the same.

I'm hoping that an overnight soak with the Trans-X will work but i'm not getting a warm feeling about it.

Should I keep driving locally no higher than 25mph? Should I take it to a trans shop? The trans was serviced before I bought it by a shop about a mile from here, and has worked flawlessly until now, however i'm sure that any shop will want to sell me more work than it needs.

Any suggestions will be greatly appreciated.

Thanks

Joe.

sixto · #2 09-21-2004, 05:36 PM

Check the kickdown switch under the accelerator pedal. Probably stuck. Disconnect and test.

Sixto
95 S420
87 300SDL

jfikentscher · #3 09-22-2004, 08:24 AM

The kickdown switch has been disconnected for a couple of years. I checked it anyway to see if the plug somehow re-connected itself. No that's not the problem.

Thanks,

Joe

jfikentscher · #4 09-22-2004, 08:36 AM

Took a ride to get the morning papers (less than 1 mile), shifted fine. left it running bought the papers same problems on the way home. shifts into second but no more.

Thought I had it licked.

Joe

jfikentscher · #5 09-22-2004, 01:44 PM

Took it to the trans shop that worked on it 4 years ago. test drove it. Started by saying internal problems. Ended with possibly the vacuum modulator. Advice here??? Please???

Thanks,

Joe

leathermang · #6 09-22-2004, 02:30 PM

Doesn't the vacuum modulator simply screw into the side of the transmission ?If so might be worth a shot at putting it on yourself...
but I would keep doing the driveway shifting through the gears with it running a little each day.... if an orifice has some flow through it the varnish can dissolve pretty fast.. but if it was completely clogged then it will take longer..
There is a moderator on this site ... Steve Brotherton... that has a transmission info site that is great.... you will need that info if you put the new modulator on ....

Pete Burton · #7 09-22-2004, 03:16 PM

You might want to pull the oil pan and see if you are getting metal flakes from inside. If you don't feel like that, try draining and replacing the fluid. If you drag a good strong magnet along the bottom of the pan first, removing it over the drain plug, you should be able to get metal particles as they come out. Use the magnet as it drains to coax it out. If you don't find anything, that should make you feel hopeful

. If you do, it might help you feel brave

leathermang · #8 09-22-2004, 03:48 PM

Pete, Your transmission has a drain plug ?

Pete Burton · #9 09-22-2004, 03:52 PM

yes, it's a 722.303 and the drain plug is removed with a 5mm allen, just like the one on the torque converter

jfikentscher · #10 09-24-2004, 07:35 AM

Thanks for the replies, business kept me from working on the car for the past two days. I'll get back into it later today.

Joe

jfikentscher · #11 10-08-2004, 09:14 AM

Part replaced. Got car back. Drove about 5 miles. Same problems.

Is there anything that might overheat and cause the car to not shift? Any electrical problems to look for? I think the trans guy is stumped at this point.

Thanks for any advice given.

Joe

Ken300D · #12 10-08-2004, 06:11 PM

You're a little bit beyond where I was, but at the first hint of a shifting problem, I switched my 87 300D over to Mobile 1 synthetic ATF. That cleaned it out and its shifting fine. I expect this was due to varnish and sludge buildup in the valve body, where tight toleranced pistons have to move back and forth inside bores.

Your problem MIGHT be the same, but more advanced. Did this come on suddenly, or has it been developing for awhile?

Compared to a transmission overhaul bill, I'm convinced running synth ATF is the way to go even though double the cost of regular ATF.

Ken300D

jfikentscher · #13 11-02-2004, 12:43 PM

Well, I have had the car back for two weeks. First day out the ball joibnt on the driver's side blew. Had to be towed to the shop. $500.00 later and new ball joints on both sides. Wish I had time to work on it myself. I thought that was expensive.

Back to the trans. Took a few short rides 1-2-miles and all seemed ok. Took a longer ride and had the same problems again. It seems that when everything heats up the trans won't shift right. won't come out of second when hot.

michael cole · #14 11-04-2004, 03:42 PM

i found changing over to mobil1 syn atf has benefited my 87 300tdt.the tranny had similar quirky behaviour.it may take a little time for positive effects

BrierS · #15 11-04-2004, 03:55 PM

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. This is on my '87 300TD.