The death knell for the trans is ringing..... - PeachParts Mercedes-Benz Forum

pawoSD · #1 07-07-2009, 03:25 PM

Sunday I went for a trip to the lake....and when I got back, I exited the freeway and was sitting at a light when I noticed a "swishing" sound under the car....but all gauges were fine and it was driving normally.....so I continued home. Noise got louder.......I go under the car (noise is loudest in park/neutral).....and find that the sound is coming from the front of the trans area.....put into drive and it goes away, until you are driving along, then it increases with the speed of the car.

This is my 1982 300SD with a 722.303 trans.

Then the next day (yesterday) I go somewhere, and when I put it in reverse it jolted back a few times and was acting up.....forward gears are ok....though a bit softer than usual, and it is randomly holding 1st gear too long. (completely random on that one)

Today I drove it to the park with my dog, when I went to leave, it took forever to engage reverse (5 seconds or so) and it was a very weak engagement.....and even touching the throttle makes it feel like its slipping and shuddering. Forward gears still work ok.

I'm guessing my reverse band is broken or dying.....and is likely the reason for the swishing noise too.....am I right on that? Trans has 281k on it....and has been flawless up till now.

I have begun the search for a used one, as I don't want to spend the $$ on a rebuild right now.

At least my 300E is driving perfectly.

tbomachines · #2 07-07-2009, 03:28 PM

Aw man that sucks

I saw your post in the other thread and was thinking the B3 band, but your other symptoms didn't seem to match up with it. Take a look at the atf and see if there is any debris in it.

pawoSD · #3 07-07-2009, 04:33 PM

Quote:

Originally Posted by tbomachines

Aw man that sucks

I saw your post in the other thread and was thinking the B3 band, but your other symptoms didn't seem to match up with it. Take a look at the atf and see if there is any debris in it.

I pulled the stick/checked it yesterday.....fluid smelled normal and no debris that could tell (wiped it on a rag a few times....looked normal. I added some more fluid (was a little low, but not a lot...it doesn't leak a drop as far as I can tell).

Last time it was serviced was at 212k it was re-sealed, and they said it looked good inside then.....though it has been 70k/5+ years since then. Maybe its time has simply come.

At least it drives forwards ok.....I'll just avoid situations needing reverse for now while I seek a replacement.

pawoSD · #4 07-08-2009, 06:31 PM

I think after much consideration I am going to have my local shop rebuild it....I'll try to pull it between now and this weekend and get it in their hands. They said anywhere between $900 and $1400 depending what needs work in there...they'd know better once they take it apart and see. They give a 1 year unlimited miles warranty, and I can go there in person, so no dealing with shipping stuff....its only 6 miles away. In the meantime, it still drags the car along, shifts are a bit softer than before, and reverse still moves the car, but it shudders if you give any throttle at all....so its a very weak engagement. (does this mean its not completely "broken"?) I figure I'd rather go for a warranted rebuild than a question mark trans that may leak or die in 20k and then I'm in the same spot and out $500......plus, I plan on keeping my car till it rusts away....and then I'll find a nice body in need of a transplant and move over at least the trans....which would still be good to go, or I could sell it as a low miles rebuild for some $$. So in the end....its worth it....at least to me. If I keep battling the rust there's no reason I shouldn't be able to get another 5-6 years or more out of my car....and at that point the chassis will probably have in excess of 350k on it.....the motor is strong and has a timing chain that's only been installed for 70k with half a degree of stretch....so it should last a long while yet....it still starts easily at 0F with no heater. Oh, and I've replaced just about everything else on the car....you name it, its been replaced.

So after this there's not much to go wrong!

rs899 · #5 07-09-2009, 07:19 AM

A one-year warranty is worthless if you are planning to keep the car "till it rusts away". That means your shop can take it apart and reuse whatever looks "good enough" to make it last a year. That means they don't have to pull apart the clutch drums and replace leaking o-rings.

If you are going this route, I would advise you to at least buy and give them new clutches to use (and get your old ones back) and insist they rebuild your clutch drums.

Rick

pawoSD · #6 07-20-2009, 01:49 PM

I have decided to go the route of a used trans....which I have obtained from a forum member....its a 1985 trans with 163k and is in good shape. If it lasts as long as the one that died in my car then I'll get another 120k out of it....putting my car over 400k. As for pulling/installing it, heck with going under the car. I bought a nifty 2-ton engine hoist today!

I'm pulling the whole unit and doing it that way, much easier IMHO rather than trying to get the car high enough off the ground to even be able to work on it underneath. I did it once already last October, I can do it again!

And now I have my own hoist....so I can take my time instead of spending $35 a day on a rental.

I'll also be able to do some other stuff like replacing the motor mounts and such....

Maybe this time I will even take a bunch of pictures. I say it every time.....one of these times it will happen!

tbomachines · #7 07-20-2009, 02:08 PM

Nice! Are you planning on gutting the old one to figure out the problem?

pawoSD · #8 07-20-2009, 02:22 PM

Quote:

Originally Posted by tbomachines

Nice! Are you planning on gutting the old one to figure out the problem?

Yeah I am going to try and find a transmission book (that might take a while) for the 722.303....and then maybe rebuild it or at least take it apart

on my own....to have as a spare.....

tbomachines · #9 07-20-2009, 02:27 PM

That would be great, I'd love to see pictures of the internals after use, could be a great resource for others on the forum.

pawoSD · #10 07-30-2009, 11:55 PM

Ok, I got the motor and trans pulled out today and commenced surgery on the old transmission. I got the tail housings swapped between them, but the bowden cable transplant went south real fast, two tabs broke off the clip/end, so it looks like a new cable will be ordered tonight.

The plastic is so old and brittle they are impossible to remove without breaking.

I also found a clumps of gray clutch material all over the inside of the pan, as well as a fairly large curved shard (smooth but obviously broke off something at one end) of metal!

Just laying in the pan...no clue where it came from. I'll get a pic up of it soon. The fluid was still red but with a gray twinge to it. Obviously some real bad stuff happened in there. When you spin the shafts by hand it still makes the "swish/scrape" noise on each revolution....so something broke and is rubbing on the case inside. Eventually I'll tear it apart to find what broke.....but I have no plans to rebuild it. Way too time consuming/too much trouble.

So once I get my new bowden cable, I'll be back in business and will proceed to re-install everything and get it back on the road! I'm getting tired of only a boring gasser to drive (they really are boring)

Its not bad...its just not the same.

I took some pics today....here they are:

Hoisting out....

Hovering....

Yoke/flange removal. You can see the special 4-notch socket in the background, used to remove early series flange nuts. It was replaced with a double hex.

Donor trans....awaiting surgery.

Random pic....gasser hit one of those cool mileages a day ago....

Hit Man X · #11 07-31-2009, 12:37 AM

Reseal it while it's out. NO easier time than now.

pawoSD · #12 07-31-2009, 12:47 AM

Quote:

Originally Posted by Hit Man X

Reseal it while it's out. NO easier time than now.

The trans was leak free when I got it, the whole case was bone dry, so no major worries there. All the same, I swapped rear covers, and the seal on the cover I swapped on was replaced only about 4 years ago, and was leak free...so I won't bother with that one. I will be changing the front torque converter seal, I have a new one on hand. That one seems to be the most common leak source. Even though the current one is not leaking I will replace it anyways since I have one.