Okay about 8 months ago my 78 300SD lost reverse. I now pull through everywhere I go.
Drive, S,L all work fine with no indication whatsoever that they are thinking of taking vacation. I checked fluid with the engine at running temp and it checked out fine. Pinky red, not dark. I do have a slightly more definite shift into second, not as smooth as it once was. Second to third is smooth.
Thoughts? Advice?
I took it to a transmission place (mom-pop, not big name) and they gave me numbers from $2600 to $4500 depending on replacement, rebuild etc.
I'm in the Denver area if anyone here knows of a TRUSTWORTHY place to take my girl.

Ginny in Littleton
78 300SD (mine)
79 300SD (beater boy, his)

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Ginny in Denver-ish
78 300SD, 265K (mine)

Ginny-

DON'T DO ANYTHING RASH.

read this thread (and the embedded one in it)

Bad news: '79 300d tranny slip reverse.

Yours has a reverse band adjustment that might be your problem. It happened to a 77 240D that I picked up cheaply because it had "No reverse".

I fixed it in 10 minutes. For free.

Rick

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80 300SD (129k mi) 82 240D stick (193k mi)77 240D auto - stick to be (153k mi) 85 380SL (145k mi) 89 BMW 535i 82 Diesel Rabbit Pickup (374k mi) 91 Jetta IDI Diesel (155k mi) 81 VW Rabbit Convertible Diesel 70 Triumph Spitfire Mk III (63kmi)66 Triumph TR4a IRS (90k mi)67 Ford F-100 (??)

I swear, mechanics are all in kahoots in Denver.

So, since the shop my car is in couldn't find or didn't look at didn't know what they were looking for, I called the tranny place next door (shop recommends them) and asked the guy to go look at my tranny and see if it has the RBA screw. He calls me back about 30 minutes later and tells me he talked to his builder and builder says it's got an adjustment internal pin and no outside adjustment. No one bothered to GO LOOK like I asked and he said he'd do.

Is that adjustment screw something that isn't supposed to be touched?
Is it like overclocking your computer? Only a few know about it and know how to do it?
I wish the car was here and I'd get down on the cold ground and look myself!
Why send a guy in when a chick can do it better?????

Thanks for listening!

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Ginny in Denver-ish
78 300SD, 265K (mine)

It pretty well has to have the reverse band adjustment. If it will repair it one way or another is a different issue.
Mercedes did not build that many variations on their common automatic. I am almost afraid in todays repair market if one can deal with issues themselves it is a far better choice.
I suspect it also applies even to newer cars when possible. My own recent example in Canada. Took wifes toyota in for a yearly safety check. Inner lower control arm bushings starting to separate from their bond on steel sleeves. Garage would change them for about 700.00 for new lower control arms from toyota. Plus labour to change them out plus we should not forget the tax. So for about a thousand dollars problem is gone. A fairly common problem on these cars here as well.
Yet the actual bushings say a fifteen dollar part are not available here. You have to buy the complete control arm.
Solution? Came home and on the web they are 82.00 each including shipping and ball joints. So 164.00 to round it off and about an hour a side to change perhaps less.
The main difference is they are not original toyota parts for starters. It is also bad the difference between farming out and doing it myself approaches 850.00. That alone though is not the true difference. In general to spend the 850.00 you have to earn it one way or another. Most people pay taxes and costs of earning money in my opinion.
This probably balloons it to say 1100 diference in cost . If you extrapolate this to a few more jobs over a given year we are talking real pocket change. The question is will you work for five hundred dollars an hour? In theory if you make say 675.00 an hour it is not bad to farm out work like this. I tend to fall a little short unfortunatly myself. Again even a person is not competent to change a lower control arm on a simple strut car he should at least source out the parts and find someone to change them. Just my opinions by the way.

i had mine rebuilt in denver by a good. i dunno if he will do another one. he said it was a PITA... but if you want i can try to see if he will do another.

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-Trevor

OBK #12
1980 300SD 333,XXX miles - Totaled
1986 Mazda RX-7 212,XXX miles - impounded and auctioned off
2005 Jeep Liberty CRD Limited 33,000- SEGR, Provent, Fumoto

Where is the reverse adjustment band located?

Ginny (and anyone else with a slipping 722.1xx four bolt tranny)

Here are some success threads:

Bad news: '79 300d tranny slip reverse.

and

722.120 Trans Losing Reverse

the second has some pictures of the animal.

Don't be thinking about rebuilds on these trannies just because of reverse-
this can be a real easy thing to fix- honest.

Not in my opinion, if it needs adjusting. Besides, what do you have to lose? It's already not working...just give it a turn at a time and see what happens.


Rick

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80 300SD (129k mi) 82 240D stick (193k mi)77 240D auto - stick to be (153k mi) 85 380SL (145k mi) 89 BMW 535i 82 Diesel Rabbit Pickup (374k mi) 91 Jetta IDI Diesel (155k mi) 81 VW Rabbit Convertible Diesel 70 Triumph Spitfire Mk III (63kmi)66 Triumph TR4a IRS (90k mi)67 Ford F-100 (??)

So, I go to pick up the baby girl today, full of heat, fresh oil change, found the block heater. I ask if the car can be put up on the rack so I can just check, for my own curiosity, and they did so for me.
I get under the car and look around the tranny, think i see something that might be it and stick my hand in the greasy mess. I twist the bolt (nothing had to be removed to get to it) and it's REALLY lose! Might have been 5 full turns until it stopped turning. I show the mechanic who is standing by with the light watching..
We bring her down, I wash my hands and we all cross our fingers.
Someone opens the bay door and HE BACKS HER OUT OF THE BAY!!!
And drives her right to the tranny shop NEXT DOOR to tell the tranny guy that a girl fixed the tranny and YES, HER CAR DOES HAVE THE REVERSE BAND ADJUSTMENT!
I jumped, I screamed with joy and I am still smiling.
Thank you Rick, you are DA MAN!

So, add me to the list of miracle reverse fixes!
AND I swear it goes faster backward now than forward!

Also, the shifting from 1 to 2 is smooth again. It used to be rather rough but now it's back to be almost un-noticable. Is this part of the RBA or is it because of the new amp? (Isn't part of he tranny run on vacuum?)

Thanks again, you all rock my MB world!

EDIT: Just wanted to add this to the end of the thread so anyone else searching in the future will see the Happy Ending!

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Ginny in Denver-ish
78 300SD, 265K (mine)