BIG problems in my 300SD (transmission)

[85drtysthbenz]

well, ive done it now...pretty sure im in deep ***** ....i went to pull away from a red light yesterday and had a huge jolt when 1st gear totally gave out...had to drive all the way back home in 3rd...2nd gear started slipping badly on the way back...it held 1st gear for about 2 seconds and then, BAM, it just went out...just like that...no warning, no slippage...

now, hows the cheapest way to go about getting my baby back on the road? i guess i could sell a kidney or something...i know theres a lot of you guys out there that have run into transmission trouble, i just need to know what to expect to spend....with diesel prices like they have been, i may just take out a loan and go buy a bike if i cant find a tranny within a reasonable range....just need some sympathy and advice....lots of advice

[dieseldiehard]

If the 1985 300SD is like the 300D, it uses a year-specific transmission. That makes them hard to find, but I saw one last month in a wrecking yard in San Jose CA. There was a thread on a different vehicle that covered various prices for reair in the Phoenix area:
722 Tranny Fixed!

[8threesd]

Does The transmission engage in reverse?

If It won't engage in any forward gears, but reverse is fine it might be your B2 piston. Although I don't think a B2 failure would have been that sudden.

It's worth checking though.

Sam

[dieseldiehard]

Doesn't sound like the B2 piston but hey, I haven't had that experience yet so maybe it is, if so that would be a blessing!
oh yes, Lots of sympathy, 85drtysthbenz
I lost a trans in my '79 (with '85 engine transplant) and it turned out the valve body cracked. I jumped on it and it stuck in 2nd gear. fortunately I was less than a mile from a shop. If that had happened in West Texas places like I was at last week, I'd really have been up the creek and no paddle.
It cost me $2500 for a rebuilt trans with some begging, a bad core you know!

[85drtysthbenz]

yes, it engages in reverse fine....theres much slippage when pulling from a dead stop...but when you get up into 3rd gear, youd never know anything was wrong with it...and yes, it was sudden as hell, although my shifts from 1st to 2nd had always been a little harsh...i think that was more a vacuum problem....but like i say, it hadnt slipped a lick before yesterday....something just popped, and murdered 1st gear....maybe this is a blessing...ive always wanted to have another mode of transportation so i can be able to do some serious work on this car...but whats funny is, im thinking about getting out of one of the safest, most dependable cars to have ever driven on the road, and getting on a metal, two wheeled death trap... go figure

[Bill.Brune]

I had this same type of experience on a 87SDL a few months ago..In fact it was the next day after I had looked the car over and advised my friend to buy it, as it seemed pretty solid. He had it out the next day, and bingo 1st & 2nd slipped and complained like mad 3rd was ok, and reverse was fine. I replaced the B2 piston & put a spring kit in (a K1, but I might be mistaken,would have to look it up). At any rate, transmission operated much better than before, and has not given any trouble since. Was about 6k miles ago. Makes me wonder how many transmissions have been replaced, when it was just a bum B2 piston..

Bill

[85drtysthbenz]

what kind of trouble is it to replace the B2 piston? what might i be looking at costwise?

Check out the DIY pages sticky at the top of the Diesel forum.
Somewhere in there, there is instructions on how to replace the B2 Piston.

I would look it up but you need to look over all of those pages anyway

BTW this sounds very much like a B2 piston failure...and at the cost of a new transmission, I would atleast give it a look-see before you rule it out.

[85drtysthbenz]

oh yeah, im definitely going to check my options before ruling anything out at all...and thanks for the quick replies, guys....id be so lost without this place...if i couldnt come here and get totally unbiased info, id be forced to go to an independent mechanic and, well...id might as well bend on over and get the lube ready ....thanks again, and i hope everyones new year has started out better than mine

[vwkess]

Definately sounds like the B2. Mine failed suddenly like that as well. It's a bit of a PITA (to do it right) if you don't pull the tranny. I did it not long ago and these were the parts I needed:

107 270 04 32 B2 Piston
005 997 70 48 B2 seal ring
126 277 08 50 plastic bushing for updated B2 piston
006 997 73 47 seal that holds in the bushing
126 270 44 77 K1 Spring Kit (not necessary, but was an updated part so I replaced it)

Was about $200 in parts. This will give you an idea of whats involved: B2 piston replacment The only reason I recommend removing the transmission is because you need to remove/replace the piston seal to replace the metal bushing with the new plastic one. It's difficult to do with the tranny in the car without damaging the bore. Unless you were/are a mechanic or are mechanically inclined and have alot of patience, you could very well damage the bore. That being said, I did replace it without removing the tranny and damaging the bore, but I'm an ex-mechanic

Just a couple of tips:
Make sure all the aluminum shards/chips are cleaned from the bore and the drain at the bottom of the bore. If those shards travel further into the valve body, it can hang things up (another reason to pull the tranny, easier to make sure it is all cleaned out)
Trans-gel is your friend. You can buy it at a NAPA store. Makes the assembly process a breeze.
Contrary to what is said in the B2 replacement link, replace the piston bore cover O-ring as well. It is easy enough to put the new one in, especially with Trans-gel. Not worth having a leaking tranny after all that work.

[dieseldiehard]

Hey, you need to find an INDY that you can trust, I'd search the Forum for shops anything near your location that is mentioned as a good place might be here, in the files at this place we call the ShopForum

[MTUpower]

If you're in Broward, Palm Beach or south of Vero Beach you need to see Dezi at EuroTech off Military Trail in West Palm Beach. Best indie in 50 miles.

[8threesd]

Its easy, i just did it not to long ago. Plan on spending about $150 on parts. The seal For the bushing is a real pain, but it only took me a couple hours to do the repair, and i'm not by any means a mechanic.

If you do it yourself watch out how you take it out, or you will loose the little push rod.


let me know if you have more spacific questions.

sam

[85drtysthbenz]

thanks guys....i just took a look at the how-to on replacing the B2 piston...doesnt sound too scary....should be a snap if i can locate a spot to lift the car high enough....


on an unrelated topic...how much of a pain might it be to replace my motor mounts while im repair happy? ive been trying to smooth out the shakes at idle, but havent gotten anywhere...ive adjusted the valves, changed fuel filters, sacraficed a virgin...oops, that was for something else ...anyhow, i figure the only other option is to go ahead and replace those mounts...has anyone done this themselves? i hear that its kind of a bear to do, but im a confident little bastard...with a little direction, i think i could handle it