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-   -   92 300E transmission help! (http://www.peachparts.com/shopforum/tech-help/81913-92-300e-transmission-help.html)

blackmercedes 12-14-2003 12:39 AM

92 300E transmission help!
 
A friend of mine has a 1992 300E and has some tranny problems. The car runs, drives, and shifts perfectly. When in gear (any gear) it makes a squeak-squeak-squeak noise that varies directly with rpm.

It went to the dealer, and they spent some time with the car, and found the noise is indeed coming from inside the transmission. They have NO idea of what might be causing it, and won't even guess without opening the tranny.

He didn't have time to leave the car, so it's still a mystery.

The car has 275,000km's (about 170K-miles) and the tranny is original. I did notice the fluid to be dark and dirty, so I suggested changing it, but not sure if that'll make any difference at all.

The car is in great condition otherwise, and I think it's worth looking into a new tranny if need be, but I am stumped by this problem. The tech even said he'd never heard a similar noise.

Anyone?

joe p 12-14-2003 10:31 AM

Well, it sounds like it broke. :D


Seriously, your going to have to do a tear down and inspection. Look closely at the park pawl return spring and the rear output shaft support bearing.


If it did it only in reverse I'd say replace the foward clutches, the apply piston is hitting the front drum. However, foward only is a bearing gone or a bushing gone allowing a drum to wander into the next part inline.



Joe

gstigler 12-14-2003 11:14 AM

Start by replacing the trans fluid. Dark and dirty fluid can cause a myriad of problems. Or, it could be a sign of more serious issues. But it is definately possible that the issues could be resolved (at least temporarily) by changing the fluid.

blackmercedes 12-14-2003 03:39 PM

I read on another forum that a fellow had a very similar problem, and it turned out to be the filter was glogged, and somehow that was causing this funny sounds-like-a-slipping-belt noise.

In all my searching, it's the only similar set of symptoms I found.

He's going to change the fluid/filter (cheap) and see what the results are. We're doing it at my place tomorrow, I'll see what that does and see what it looks like when we drop the pan.

He's a little disappointed at the short tranny life, but 170K-miles isn't that bad.

haasman 12-14-2003 04:43 PM

blackmercedes

If the trans has been neglected for quite some time (fluid dark brown etc) you may want to change again in 1k miles or so.

I assume you will be draining the torque converter as well.

Haasman

glenmore 12-15-2003 11:16 AM

If the evaporator repair is considered the top $$$ repair on the W124 hit parade, then I just got past the #2 repair, the headgasket @127k.

While talking with my indie, he suggested that my engine was now good for another 100k (knock on wood).

We touched on what else could happen in this mileage range and he said the the tranny generally lasts between 150k-200k but not to fret because this was a routine repair, parts readily available and this guy up the street does them all the time for around $1500. (the head gasket cost me $1675).

So my impression was that a rebuilt tranny was down the list on the W124 worry list.

glenmore
1991 300CE

blackmercedes 12-15-2003 12:46 PM

It's apart right now, and man is it rough in there. The fluid is shot and the filter is completely clogged. He hasn't done a service on the tranny since 1997 and lots of miles later it's UGLY in there.

However, there is no debris (amazing if you ask me...) and it seems fine otherwise. Can't believe this tranny was still shifting and driving so nicely. Tough unit!

We've got the wrong pan gasket, so we're going to break and get some parts. Probably won't button it up until later today.

(And we got the torque converter drain too, of course it was at the top to start...)

And a Mercedes rebuilt unit is about $2500CDN parts and labour, at the dealer.

gstigler 12-15-2003 01:56 PM

Didn't change the fluid since 97???? Ouch! A lot of people change their oil every 3000 miles and figure thats enough in terms of maintenance. It would be much better to change oil every 6000 and trans every 25000. Would cost about the same with the same results.

It sounds like the trans might be saved by changing the fluid and the filter. That a testament to the durability of the MB trans.

blackmercedes 12-15-2003 02:15 PM

Quote:

Originally posted by gstigler
It sounds like the trans might be saved by changing the fluid and the filter. That a testament to the durability of the MB trans.
Here's hoping. Doug's back with our parts now, and we're going to do some other stuff too. Got some plugs, plug wires, air filter, fuel filter and a new Poly-V-belt.

Finish lunch, then back to work! Operation 300E revival!

(Hopr this works, Doug has done about 1000 favours for me over the years...least I can do to help)

blackmercedes 12-15-2003 05:03 PM

Engine work done! Got the new plugs in, new wires (the old ones were looking pretty sad) and an oil/filter change. Swapped the new Poly-V-belt in. New engine air filter and new fuel filter. Everything is looking pretty good now.

Taking a little break before finishing the tranny work. We have the right pan gasket now, which will make the final work much easier!

Worst case is that the noise is still there. The plan is then to drive the car until the trans fails or at least shows some signs that something is not right (still baffles me that it was working so well...)

Probably a couple more hours to get the tranny finished and everything double checked. I left the pan off to make sure every last drop of whatever might feel like coming out has. Black fluid, gummed up filter, but no visible clutch material or other bits.

In January we'll tackle the front flex disc and final drive oil change, plus the rear brakes are looking like they're going to need attention soon. Getting this gal back into fighting shape is a bit of a task!

The car was a very good price with the lack of TLC reflected in the purchase price Doug paid, so he's not feeling too bad about siking some money into her. He had just lucked out getting out of a lease on a rotten Explorer and loves the 300E so far. Even if it needs a new tranny, his total investment is a fraction of the price of a new car.

I'll post the tranny results later...

blackmercedes 12-15-2003 08:37 PM

Didn't Work
 
Well, the car runs like a top and the tranny seems perfect. However, we have not solved the tranny noise. Talked to a tech and he thinks it might be either the front pump or the torque converter. I have no opinion on that, but I do know it's not fixed.

Oh well. The rest of the car is now in decent shape, and he's going to drive it for a while and get some more miles out of the tranny.

ericnguyen 12-16-2003 12:18 AM

Dear blackmercedes:

Don't get frustrated yet! Try to put about a quart of Trans-X in the transmission and drive for at least 500 Miles before jumping to the conclusion that the something is seriously wrong in the transmission. If the ATF was dark and dirty, it may be possible that varnish might clog the intricate innards of the transmission and hamper the ATF flow, causing all kinds of unknown problems.

Good luck!

Best regards,

Eric

Merc380SE 12-16-2003 05:06 PM

This might be a cracked flexplate ( engine to torque converter )
Difficult to inspect without removing tranny

plink49 12-16-2003 08:50 PM

I don't know if this means anything at all in regards to your particular problem, but 2 years ago this month I took my '86 300E (194,000 miles at the time) to the local MB dealer (one of the better ones I am told!) because the tranny was leaking fluid. After doing a thorough inspection by their senior mechanic I was told that I should not spend the $2000 to fully rebuild it, but rather to check weekly on the fluid level, top off when necessary and put a piece of cardboard on the garage floor! In essence he told me the tranny in that car is mechanically a bullet-proof workhorse that should go at least 300k miles if not 400k miles if not more as long as the fluid is kept new and at proper levels. 2 years later it is still one of the smoothest-shifting transmissions ever built....and well after 202 thousand miles! Moral of the story is: If, as you say, it is running/shifting flawlessly then the squeak shouldn't be anything to be concerned with. Moral #2: Can you believe a MB dealer would actually tell you the genuine truth and not try and pillage your bank account!:rolleyes:


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