94 S500 Transmission problem
 

My 94 S500 has 180000 miles on it, eversince when it had 110000 miles,everytime I shift to Reverse gear it always had couple seconds delay, but now it's getting BAD, when I shift to Reverse gear now, it's getting slippery and strange noise comes from the bottom of car (should be transmission). what should I do to this problem??

Unfortunately you need to have it overhauled. It undoubtably must be the clutch pack for reverse which is a common failure.

This is also a problem that is best fixed promptly, if one wants the cheaper road of having that unit rebuilt. If the answer becomes a rebuilt MB unit w/torque convertor it doesn't matter.

The failure is such that as rev starts slipping the clutch material is mostly in the pan and filter. As the thing starts singing and catching the frictions are metal to metal and the resulting mess goes everywhere. The damage is easily fixable but the mess can get into the valve body, governor passages, etc. and come back as eternal shift irregularities.

so what exactly parts do I have to fix/change?? and do you know how much will it cost??

Thanks!!

I think a rebuilt unit is $2200.00 installed at an MB with a 24 month warranty



Warren
1992 300SD
Columbus Ohio

180K-miles on the auto-box? That's respectable mileage. Most I've seen begin to age after 150,000 miles. Three of my old-sold cars have very high miles, and needed auto-boxes sometime before 250K-miles.

Could be a Chrysler. Would have been through a half dozen by now...

blackmercedes,

Now that MB and Chrysler are in bed together, should we expect MB trannies to conk out more, or Chrysler trannies to get better?

-just wondrin"

Well since many MB's are actually cheaper than they were 10 years ago..I think you can probably do the math on that one....you usually get what you pay for



Warren
1992 300SD
Columbus Ohio

reverse on MBZ tranny fix
 

The reverse clutch pack is right behing the front pump--the first part removed on disassembly of the tranny. Replacement of just the reverse clutch pack at a good tranny rebuild place should cost only $150 or so, plus the labor to remove/reinstall (6-8 hrs)

can you tell me what is the part number for reverse clutch pack? and beside dealer, where can i buy it??

Appreciated !!

Regards,
Stephen

If that trans had 75k on it and you caught the problem early it might be worth the risk to only do the reverse clutches.

The reverse clutches are such a problem that we have often considered doing them with front pump seals. The whole question is made mute when one considers the age. We now very seldom do just front pump seals on cars over 125k. The seals fail at about the same time and doing half the work to replace one seal (or even in this case clutches) is poor economics.

In the case of rear clutch failure, you are going to have a muddy mess for sure in the trans. All that clutch material is in the oil and spread everywhere. It often plugs the filter and is the final straw. If you wait till they are metal to metal the mix is near terminal. Anyone putting just clutches into that mesh is doing you no favor.

We do the 722.3 trannies about 25 a year. A front pump seal/rear main oil seal (you are there why not reseal the motor) would cost about 700 with filter and fluid. Doing rear clutches would add about 200. We disassemble, clean, replace ALL seals (including servo pistons, clutch lip seals, etc), all clutches, thrust bearings, and make all adjustments internally and externally for about 1500.

We hardly ever do less than the 1500 for an old tranny (that needs any of the above) and 180k is an OLD tranny. They call it rebuilding. I call it a 150k tranny service.

The clutches for reverse are MB# 126 272 09 25 and list for $9.25 each and there are 4. They are stacked together with the metal clutches which are likely also bad. They come in various thickness to achieve proper endplay of the stack. The thicknesses are 2.3, 2.8, 3.3, and 3.8mm the smallest cost 36 and the largest costs 19 (figure that).

Could you not get a rebuilt complete MB tranny with a 2 year warranty for just a few hundred more?...seems to me a rebuilt is the way to go


Warren
1992 300SD
Columbus Ohio