Sourcing a good transmission 1982 300TD

[ubertino]

It looks like I have the luxury of some time to source a new transmission for my 1982 300TD, 184,000 documented miles. It works fine, but there is a bearing howl coming from the transmission, verified by my shop.

So it works, but for an indeterminate length of time.

I need to find a replacement transmission.

Anybody with experience have some wisdom to share? Used, rebuilt? From Bob's repair shop or a big national outfit?

Also, I have an indy shop that has specialized in old german cars for 30 years, with guys who have worked on the brand since the 70's still wrenching (they have no turnover). They're not the $tealership, but are pricey, and do a great job. I also have an excellent shade tree guy with good history, a garage with lift, and good mechanical instincts, but not as much experience with a w123. What are your thoughts?

Thank you!

[shertex]

Speaking of instincts....sounds like you have a great indie. My gut says let them source the tranny and do it for you. I'm sure you'd pay a bit more, but I bet you'd have a lot of peace of mind.

[vstech]

184K... and a bearing noise? which bearing? when is the noise present? I'd think any competent shop could fix a bearing in these...

[ubertino]

Originally Posted by vstech

184K... and a bearing noise? which bearing? when is the noise present? I'd think any competent shop could fix a bearing in these...

The noise is related to engine speed, and it's unmistakably bearing howl. Starts of low and quiet, gets higher in pitch and louder as the rpm's go up. Because its rpm dependent it is likely one of the bearings at the front of the transmission.

The worst is that the transmission works just fine, a little hard on the shift to first, and a tiny bit of flare at wot going from 3-4, but good working.

The shop I'm using is the most reputable shop on this side of Michigan, and one of the better ones in the Midwest, Arie Nol (Dutch name). Jeff, the service advisor said that with the age of the car and the miles, a rebuild or low/ish mileage transmission would be better then replacing the bearing. That said, they're not a specialty transmission shop, but they are also the only ones that I've found who know what a vacuum diagram is, and understand the shifting mechanisms and tuning of these old MB transmissions. All of the speciality shops are confused by the question.

Vstech, if you have an idea of how I might do this without replacing what is, functionally, a good transmission, I'm all ears. The car drives great, but the noise and vibration are unpleasant, and I'm worried about the consequences to the engine if the bearing seizes.

[Mölyapina]

I suppose that if the howl varies with engine speed it's got to be something related to the input shaft, right?

[ubertino]

I don't know about the shaft bearing, but it makes a lot of sense.

[sixto]

How about taking it to that '70s shop for a second opinion? Otherwise I'd be tempted to gamble on a new front pump.

To extend shertex's point, your best bet for a meaningful warranty is to have the shop that installs the transmission source the transmission. Otherwise there'll be finger pointing if there's a problem. FYI, it's typcial for shops and rebuilders to insist on replacing the torque converter when replacing the transmission to qualify for warranty coverage.

Sixto
87 300D

[ubertino]

I have some time next week, I'll physically visit several shops to see what they say.

Any other thoughts? eBay has a manual conversion kit, tranny, pedal box, etc. I've thought about it, my shop says its probably not worth the cost. I don't have the time to do it myself, which is a problem. I can spend a few hours here and there, but not an entire weekend.

[Mölyapina]

A manual tranny would be awesome . I would think that a professional shop could do that within two days, given how well documented it is on the internet.

[ubertino]

I've dreamed if it for years. I've only talked to two shops about it, and neither would touch it because of all if the unknown problems- issues sizing drug shaft or shift linkage, bell housing or pilot bearing alignments, reverse light wiring, etc.

I do have a brilliant shade tree artist, he put a h6 3.0 Subaru engine in an 84 vw vanagon, and it's reliable and bat**** fast. He's not afraid, but is also unwilling to promise a drivable car.

I'd do it, but I'm without the amount of availie time required. Especially if any of the project is not plug-and-play ala the write up (which I have book marked).

[Mölyapina]

I would think that if your shadetree can do that, he can do the manual tranny conversion.

[ubertino]

A quick update: I decided to check the transmission fluid myself, and lo, the fluid is low, just a bit below the bottom notch. Car nicely warm, parked on level ground.

The pump in the front of the transmission might be protesting the lack of fluid. I'm picking some up tomorrow, and I'll be topping it up.

I might just get lucky. Otherwise, I'll be consulting my shade tree mechanic. Who has an air conditioned/heated shop. And a lift. And airtools.

[cho]

Originally Posted by ubertino

Any other thoughts? eBay has a manual conversion kit, tranny, pedal box, etc. I've thought about it, my shop says its probably not worth the cost.

plug and play option HERE

but sourcing a good auto over there is much cheaper solution



.

[ubertino]

So the plot thickens.

After a short drive, I decided to check the transmission oil, mostly to see what it smelled like, since a bad bearing will probably burn some oil, and the more burned the oil is, the worse the bearing (tell me if my logic is wrong). I discovered that the oil was low, below the minimum mark, so I topped it up.

Now the noise is very different, reminds me of a loud power steering pump without enough fluid. For the first mile, at low speeds, the noise was intermittent, which was nice, now it's presenting at the same times as before, but with the different sound than before.

I'm thinking pump? Which is replaceable, rather than the whole transmission? Or would going from low fluid to normal fluid change the noise of an input shaft bearing?

[ubertino]

A short video so you can hear (badly) the sound the transmission is making.

Transmission Sounds - YouTube