I know this is not an uncommon problem, works okay on the flat, hard or impossible to go uphill.

So I found this thread:

http://www.peachparts.com/shopforum/showthread.php?t=151936&highlight=slip+reverse

Post #6

I don't have my manual with me to figure out which tranny came on this model. Someone here will know. So the question is: do I have the external adjustment bolt for the B3 reverse band? Two local part-time Mercedes mechanics disagree with eachother on this. One says "Yeah that helps sometimes", the other says that there is no external adjustment.

I might have become the latest old Mercedes buyer to stumble into buying the wrong car. I don't recall noticing this problem when I did the test drive. I bought a car that has 110k on replacement engine but might need replacement transmission. I feel sick to my stomach.......

Caveat: My terminology might leave something to be desired.

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1979 300D 275K

Yup, you should have the adjustment bolt, if your tranny is the four-bolt oil pan 722.1xx, which is what the NA 300D had.

Good luck. I never saw that other thread before, but it's a good explanation and pix.

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 (??)

Thanks for the reply.

I spoke with the folks at **************.com (the Bergsma family) who assured me that there is no external adjustment that they had ever heard of. I can't wait to get under there this weekend and see for myself! In the link above, it mentions that this bolt may need to have a slot cut in order to be able to turn it. That seems like a frustrating proposition. Any ideas?

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1979 300D 275K

Yep, I have confirmed the transmission is a 722118 so I will be reporting back next week on my attempt to make that adjustment.

The thread I linked mentions that I will need to drain the transmission fluid. So I will replace the filter at that time. Any thoughts on tracking down the K1 spring upgrade and doing that at the same time? Having not driven another example of the 300d, nor having had anyone with more experience drive mine, I'm not sure if I am experiencing "flare" at the 2-3 shift. It does seem like it should shift earlier and I did learn today how to induce a shift by letting off the throttle so.... Is there any harm in installing the new K1 spring?

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1979 300D 275K

The 722.1xx family do not have the K-1 spring issue that the 722.3xx family has. I don't think there even is a K-1 spring upgrade for the 722.1xx

I don't see why you need to change the fluid to tighten the reverse band. It's a good idea, but not needed just to try to fix this issue.

Sounds to me like you need to adjust the bellcrank lingage on top of your valve cover to change the timing of your shifts. This operates like the bowden cable on the later transmissions. Do some more reading here about transmission modulation adjustments and you can probably improve your transmission.

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 (??)

Hopefully i wownt start a pissing match by saying this but i have always found ************** to be rather useless for everything except certain repair kits.

Clearly, I need to keep doing my research! Thanks for the tip.

The shifting has taken some getting used to but at this point seems like something I can live with. Wish I had something to compare it to.

I will put "adjust bellcrank housing linkage" on the to do list (after fix exhaust, valve adjustment, coolant flush, change fuel lines, brake fluid flush, change brake pads, diesel purge, trace vacuum leaks, etc, etc, etc)

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1979 300D 275K

For the record, I was in no way taking issue with the folks at **************. They have been very helpful and I have certainly learned a lot just by perusing their website.

Merely, I was commenting on how everyone has an opinion, and rarely do the opinions agree! Back when I used to change the spark plugs in my old truck, I would put in XX brand plugs on the recommendation of the guy at the parts store ("I wouldn't use anything else"). The next time I go looking for a set of XX brand plugs the new guy at the parts store recommends YY brand ("I wouldn't use XX brand as weights in my crab pot").

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1979 300D 275K

So I finally got a chance to locate and adjust the bolt in question.

I cleaned around the kickdown solenoid as well as I could (not much room to work in that area) and removed it. I made a tapered plug out of a clean piece of wood that threaded into the solenoid hole, in order to not drop bits of road grime in there. I cleaned around the adjustment bolt and then.....got cold feet. I couldn't find the nerve to pull it out. Another thread warns of losing a small pin down into the transmission and there is so much grime under there that I was sure to get gunk back in when replacing the bolt. I did get a socket on the lock nut and snugged it back up (took maybe 1.5 turns). The actual bolt turned along with the nut.

Test drive: Reverse definitely works better. It still feels as though some slip is happening but then again, I'm not sure how low the reverse gear is. I am now able to back uphill without having to stomp on the peddle to keep up momentum. There is a slight whine in reverse now that I hadn't noticed before.

So, does it sound like I did the right thing? Since I didn't follow the "snug it up and then back it out 1 1/2 turns" suggestion, have I now created a situation where I'm doing damage? Thoughts?

PS Also successfully changed out front brake pads for the first time(and not a minute too soon).

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1979 300D 275K

I think you did some good- I wouldn't be worried about over tightening with 1.5 turns.

Were you able to get the adjuster to rotate independent of the locknut?

It was I who warned about losing the inner stud into the bowels of the transmission. I don't really know if that is possible. Do a search on here about 2 months ago 2 guys were having the same problem and I think one of them took the bolt set out completely.

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 (??)

Thanks for the confidence boost.

No, locknut and adjuster turned together.

If I were to do a pressure wash under there and was more sure about not losing the inner stud in to the depths of the transmission, I wouldn't hesitate to pull it out completely in order to cut a slot to engage a screwdriver. Only problem I can see is holding the stud with the screwdriver while also snugging up the locknut. It didn't seem like there was enough room to get a spanner in there. Maybe so.

I wonder how many transmissions have been replaced that could have been fixed by making this adjustment. Worse, how many cars have been scrapped because the owner thought the tranny was dying and didn't want to spend the $$ to fix it?

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1979 300D 275K

Good point. I'll bet it's a significant number

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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 (??)

did this service yesterday as a customer left the island and decided to give her car to me rather than ship it back to the continent.
This is what I did to fix the reverse that had not worked in 13 years:
Place drain pan under transmission
Remove phillips screw with the wire coming off it on the front right bottom of the transmission
Remove kick down switch with 23mm open end wrench noting position
It will leak about a quart of fluid
Now that the reverse band adjustment bolt is accessible
Loosen locknut on reverse band adjustment 19mm socket
While holding lock nut, screw stud in clockwise (mine took four revolutions)
Retighten lock nut
Reinstall kick down switch and Phillips screw
While it was still on jsckstands I started the car depressed the brake and shifted into reverse…
AND FELT IT ENGAGE RECERSE FOR THE FIRST TIME IN OVER 13 YEARS!

Or you could screw the stud all the way in til you feel tension then back it off 3/4 of a turn

Before I'd do anything else I'd clean it well, this doesn't require a pressure cleaner but no matter what you're going to get filthy so dress accordingly .

The adjustment is a good thing to do but so is checking and adjusting the operating pressure, again not difficult but important to clean off the 30 + years of road grime first .

Plenty of D.I.Y. how-to's on this job too .

Don't be afraid, I was until I tried it, it's just one more simple thing old German cars need .

Unless the tranny fluid is bright red and smells sweet, it needs to be changed and the filter too along with draining the torque converter .

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-Nate
1982 240D 408,XXX miles
Ignorance is the mother of suspicion and fear is the father

I did then what I knew how to do ~ now that I know better I do better