What is the Lifespan of a well maintained W123 300D transmission?
 

What is the Lifespan of a well maintained W123 300D transmission? Its winter project time, and I was thinking of rebuilding my old failed unit. I got about 320,000 on my previous unit which came on the car when I bought it, but it had a trailer hitch on it...the one I replaced it with had 212K on it, but I don't think the maintenance was that good because the fluid was practically brown.........

I don't know how well the PO maintained my 300D tranny, but it was starting to flare around 200K and I replaced it with a reman. at about 250K. Hopefully, the new tranny will do better. I'll let you know in about 200K miles.

I got 168Kmi out of the first transmission, but that one died due to a leaky cooler hose and an inattentitive teenage driver. Probably would have been good for quite a bit more otherwise. I've got a neighbor with 365Kmi on the original in his 1985 300SD.

Is the cooler hose, that "hiss" sound I hear, while accelerating from a stop? Sounds like it's coming from below the driver's dash. Is that good?

220k with mine, it slipped from 2-3 a tad and made worse by the harsh 1-2 shift. I ended up replacing it when the B2 broke for $1200 for comfort reasons but I estimate I could have babyed another 50-70k out of it.

My SD had its trans done by the po at about 150k but I don't know the exact mileage.

The SDL is still on the orignal at 254k and it shifts pretty well. I would be surprised if it doesn't need a rebuild before it rolls over 300k.

A lot depends on the driver and how the car was driven. Highway travel wears a trans much less then around town driving.

It seems like most last around 250k, but some get a little more.

Mine was starting to misbehave a bit around 240k, and was rebuilt. Works wonderfully now at 260k.

peace,
sam

Does 'flaring' mean the xmission is done?

I was hoping that when I get the oddball vacuum issues sorted out that
my 318K 83 300td xmission would calm down.

Mine 'flares' betwixt 2-3 and 3-4 sometimes. If I manually shift it, it doesn't do it.

It also 'chunks' into reverse. I was thinking that once i sort out the vacuum, and
fiddle the modulater some, , , well, maybe that's wishful thinking.

What's a reasonable price to pay for a rebuild? I have no sense of these things.

I wonder what influence good maintenance/oil type has on the trransmissions? Both my cars, the 84 300TD and the 85 300 SD Turbodiesel have just under 300K miles. both have the original transmissions. I change oil about every 30 K miles. Never used synthetic oil.

Would it be recommended to continue as before or change to synthetic oil now? Are the seals, hoses etc. compatible for synthetic oil?

If you recommend a change to synthetic, what type would tyou recommend?

What are the high milage/no problem transmissions on the forum?

Lots of questions in hope to get more miles out of my trannies.

408k on Strider.

Are these Miles or Kilometers? Synthetic oil or standard Transmission fluid?

231k on mine so far, changed over to synthetic fluid 2 months ago, also had the seals all redone by the dealer at 212k, and they said it looked great inside and should last a long while yet. With my vac probs fixed it no longer flares, ever. Seems to work great. I am shooting for 300k+!! The way it is running currently I see no reason why it shouldn't last at least another 70k.....

Miles for mine. Only conventional has ever been used BUT, it was always MB brand. Maybe that's the trick.

Aren't they suppose to last a "MILLION MILES?" lol

Thanks TENKNOTES, very re-assuring! I'll try and follow, will stay with standard transmission fluid and hope to make it a million miles! Half a million may be all right too!