1995 E420 transmission slipping in 1st
 

hi,

my 1995 E420 has 166,000 miles on it. I just had the transmission serviced (routine), and today the tranny would slip when trying to start in first gear. This happend at a stop sign. I pulled up to the intersection, stop, then accelerated gently. The tranny then slipped out of gear and would not reengage until I stopped the car and manually pulled the shift lever to low. Once under way, the car seemed okay. At the next stop sign, the same thing would happen again, and the same technique (rowing the gearshift) would allow me to limp home.

Once home, I checked the tranny fluid level and it appeared normal.

What could be wrong? Is it time for a rebuild (or swapping out a rebuilt unit)?

How much would this cost? I'm in San Francisco, if that makes a difference

Thanks,

Warren

There isn't any compensation for worn B2 band & sounds like yours is worn.

Either have some trans shop remove the B2 piston & measure the clearance on the B2 band & adjust by installing a longer compensation "pin".

Hi MB Doc,

Thanks very much for the information.

Would it be advisable to just fix the worn component, or would shops recommend a "rebuild" (whatever that means)? I just want to know what to expect from the transmission shop.

--Warren

That repair (adjustment) can be done in 2.5-4 hrs. $300-$400

Replacement is $$$

along these lines...
 

Reverse in my 93 400E takes 3-4 seconds to engage, and usually grinds, sounds like marbles, when the car moves. Also, low-speed 3-2 downshifts (when slowing to make a turn, then accelerating enough to cause a downshift) are very clunky, a mild "bang." WOT 3-2 downshift is smooth, and normal to full-throttle upshifts and downshifts are smooth. The car has 165k. Should I wait for an eventual rebuild, or should I address the 2 issues I have now? It would seem the rest of the trans operation is flawless. What components need to be addressed, and how much?

I'd recommend a rebuild. If they're going to fix the well known/documented reverse problem you're experiencing & have the tranny out, best have a rebuild of all the normal wear parts. Just my opinion & experience.

ditto,that trans needs rebuilding from your description.

Kinda what I thought. I think I'll wait until it grenades.

So I should just have this repair/adjustment done and not do a rebuild. That's fine, but I'm sure you won't be surprised at the next question.

Does anyone out there know of a good Mercedes transmission shop in San Francisco?

Thanks again,

Warren

I wouldn't do that if this car has a transmission intercooler in its Radiator. Metal shavings have been known to lodge in that radiator for some time and then break lose later to re-enter the Tranny and cut up seals and things like that.

If you do chose to go that far I would insist (or better yet provide) an inline filter to the return line from the (intercooler) radiator to the transmission to catch that. Magnafine makes a nice little inline filter for this, has a bypass for if it gets clogged and has a nice Magnet in it.

Huhmmm

Interesting. Well. I was probably exaggerating a bit about grenading. It certainly performs fine in most situations, I just have to be careful about how I throttle it when I am in these known-issue shifting situations. I generally avoid the low speed kickdowns by throttle management. I would hope I'd get slippage before it was about to die, and currently, I have none even at full-load.

Well... I had it happen on a completely different vehicle so I felt I should mention it. In my case it was a F350 Dually trans. Ford rebuilt it under warranty after it grenaded but they left the original cooler in there... (later on to find they were rebuilding them again from this and issued a TSB on it) and, in my case, 30K later the pump seal was leaking and metal was found in the pan. Since it was now out of warranty by years not miles, I rebuilt it all again on my dime with the (now recommended even by Ford) magnafine in there. I did some other upgrades to it as well since it was on my dime. Still running strong to this day.

I don't know if this is applicable here but it is something to think about. Their later TSB called for replacing the Tranny cooler completely when doing a rebuild. This one had both. An intercooler and another aux cooler as well. They would backflush the intercooler and replace the Aux and then install the magnifine filter as well in the return line. .

Hey.... how about slipping only in reverse? Anyone got a diagnosis on that. Looking at a car that does that and trying to figure out what to offer. Full rebuild or simple fix?