Help! Transmission conked out

[azitizz]

What may be the possible causes of my automatic transmission ceasing to operate on my 1985 300TD.

It happened al of a sudden, reversing for a little stretch then putting it in park there was some funny noises idling, then it stopped. Now nothing shifts. Engine revs up in all gears but nothing happens.

I replaced the B2 piston about two years ago, so I doubt its that but could it be?

Any other Ideas and what the remedies would be?

[oldsinner111]

leaks?Fluid?Modulator sucking fluid?Front pump gasket failure?Trans cooler in radiator rotten,letting coolant in trans?I have 358,000mi on mine,but I watch for trouble.

[barry12345]

Front pump in the transmission might have sheared the connections. I know little of automatics but opening one of the transmission lines to the transmission cooler should tell you if the pump is still pumping.

[BillGrissom]

When you actuate the shifter, do you feel it click into each gear? Could be your shift linkage simply came loose and the tranny is staying in P or N. Has happened to me on several vehicles. My 96 minivan is particularly prone because they secure the shift cable at the tranny end with a plastic push-in grommet. Your car has a solid rod, but the nylon bushings fall out, leaving play, and the rod can drop out of the hole if the metal clip on the end corrodes off.

You did check the oil level? That is actually harder to verify than it sounds. When refilling a tranny, I often see oil on the stick when I know it is still 4 qt low. That can come from splashing when the oil is really low. Not enough oil, no torque converter drive.

[azitizz]

There is no sound of engagement of the gears when I shift from P to D or R or any other speed.

There is a clunk that has been there for a long time, and is still there. if i rev up the engine, I can hear the clunk more when I release the pedal. its a little delayed, When it revs up it clinks a split second after and clunks again when I release.

Also there has been some play in the mechanism that is supposed to keep the car from moving when its put in park. Doesn't seem related but perhaps.

I do need to monitor the oil regularly as there is a leak. When Its become too low I can tell by the gears not shifing, and then Ill immediately add some if that ever happens, and shes back to normal.

[97 SL320]

Will the car hold in park? The trans output flange tends to wear the splines out resulting in no drive or park holding.

[azitizz]

The Car still holds in Park, but I never checked to see if it held in drive or if it was just like being in Neutral. I was able to tow it in Neutral, so there is shifting going on between P and N, but nothing for R or D.

[pwogaman]

Perhaps the B2 piston pin worked its way loose.

[97 SL320]

Elevate the rear wheels and see if the trans will drive and reverse. It will likely drag along forward even in neutral due to internal friction so disregard that.

[Diesel911]

People say if the B2 Piston or B2 Band is the issue reverse should still work.

You did not mention the Trans Fluid level or if the Fluid smells burnt or is discolored.

[azitizz]

Right, I remeber hearing that about the B2 Piston. I just checked again and the car rolls like its in Neutral, weather its in D or R. Fluid level is back to normal, It was a little low, but Ive had it lower and it still worked before.

Doesnt smell or look burned.

There is a small amount of friction it seems when putting it in drive like it wants to edge forward but doesnt move more than and inch or so...

[Zacharias]

The way it happened sounds very much like when the front pump self-destructed on my 722.120. Sorry to have to tell you that.

[azitizz]

Is there any way to confirm or rule out the front pump is the culprit?

Is it something within the transmission housing? Replacable?

Im planning on picking up an 83 Wagon this month, assuming it has the same transmission, I may be able to get parts off it or swap it out completely.

[97 SL320]

Disconnect both transmission cooler lines from the rad, place them in a bucket and have someone start the car, if fluid comes out in a strong stream the pump is likely good.

You can also put a pressure gauge on the trans and look at line pressure. ( there should be pressure taps on the outside. )