I recently changed my 1981 non turbo 300d trans/torque converter fluid and filter after my reverse gear required full throttle to fully engage. This only started 2 months ago. All other gears work fine. After fluid change it engaged on first startup on flat ground but since then it is doing the same thing. It will lock into gear after about 1 second but will just creep along until I give full throttle for it to fully engage. Once locked in reverse gear it works fine. I am going to work with the reverse band adjustment since it is a 722.1 transmission. Can someone help with what else it could be.

Also for reverse band adjustment, after you loosen the 19mm bolt do you just turn the adjustment screw with a flathead screwdriver? Should I tighten or loosen the screw?

Step by step photo tutorials will be very helpful

I am guessing but since you want the pinch the Trahsmission band closer together I believe you would turn the inner Screw inwards.

From what I have read. My own transmission does not have the Adjustment you are speaking of. On some of the older Transmissions the Rear Band adjustment screw was made with some sort of tamper proof Screa where the Head is made to break off while others have an unmolested adjustment screw.

There is at least on thread about that.

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84 300D, 82 Volvo 244Gl Diesel

Pictures of the reverse band etc are here =>

http://www.peachparts.com/shopforum/diesel-discussion/304903-722-118-automatic-transmission-rebuild-monster-diy.html

Considering the work you have done so far however I say you are best off making absolutely sure that you have the correct fluid in the transmission. What you describes happens with an incorrect fluid level.

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1992 W201 190E 1.8 171,000 km - Daily driver
1981 W123 300D ~ 100,000 miles / 160,000 km - project car stripped to the bone
1965 Land Rover Series 2a Station Wagon CIS recovery therapy!
1961 Volvo PV544 Bare metal rat rod-ish thing

I'm here to chat about cars and to help others - I'm not here "to always be right" like an internet warrior



Don't leave that there - I'll take it to bits!

Ok, from what I have read the fixes could be the adjustment band bolt/stud, replace servo unit seals, check for faulty fluid level, or rebuild the trans. My dipstick is currently reading right in between the lower max and min lines with the car running in neutral. All the other gears shift as usual. I know that the reverse is hydraulic while all the others are controlled by vacuum. Should I add above this dipstick max line and see what happens or try trans-x before adjusting the reverse band?

The Tansmission is supposed to work best with the Fluid leval within normal limits. Also as long as there is the correct amount of Fluid there is a pump that is supposed to supply the pressure.

Also note that all of the Bands use Hydraulic Pistons to operate them. The Vacuum works on the Transmission Modulator and the Modulator adjust the Hydraulics.
There is the basic Hydraulic Pressure that the Pump puts out and then there is the Transmission Modulator adjusted Pressure that the Modulator controls.

I don't think the Trans-X would hurt anything. However, I think some addatives are somewhat like STP in that they make the Fluid thicker and that brings the Pump Pressur up.
They also sometimes have some chemicals that cause the Sealing material to swell and seal better.
None of the above is going to fix an out of adjustment Reverse Band or a worn out Reverse Band.

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84 300D, 82 Volvo 244Gl Diesel

You don't check the fluid in these cars with it idling in Neutral.....once the car is up to operating temp, sort drive around a few blocks....pull over....move the shifter through all gears and then place the shifter in Park.....now check the fluid level...

Also check all your gear shifter bushings, there's a good chance one or all are rotted away...

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My own Transmission engages a little hashly in Reverse. If I had a Band Adjustmet screw I would try that.

However, what I really should do is check the Pump Pressure and then Check the Modulator pressure to see if they are within specs.
If the Modulator Pressure is off I should reset that and then see what happens with reverse.

If none of that helps then if I had the Band Adjustment screw then would be the time to try that.

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84 300D, 82 Volvo 244Gl Diesel

Additives probably won't help.

As mentioned above you need to adjust your method of checking the fluid level. 80 degrees C is the magic temperature - clean and re-insert the dip stick several times to make sure you get the same reading.

Checking the fluid level on these transmissions is more anal than trivial.

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1992 W201 190E 1.8 171,000 km - Daily driver
1981 W123 300D ~ 100,000 miles / 160,000 km - project car stripped to the bone
1965 Land Rover Series 2a Station Wagon CIS recovery therapy!
1961 Volvo PV544 Bare metal rat rod-ish thing

I'm here to chat about cars and to help others - I'm not here "to always be right" like an internet warrior



Don't leave that there - I'll take it to bits!

Band adjustment locknut was too tight to loosen, and the adjustment screw was too tight to turn with a screwdriver while locknut was still tightened... I will update soon after I adjust my fluid level...

You might be a bit frustrated by the screw not being screwable but in the big scheme of things it might not be such a bad thing. You can check the amount of travel in the band if you remove the valve body =>

See post #36 in the thread I linked earlier

This can be done with the transmission in-situ

However, if you remove the valve body to do this "the wise" say it is best to put on a new gasket to make sure you don't get random leaks...

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1992 W201 190E 1.8 171,000 km - Daily driver
1981 W123 300D ~ 100,000 miles / 160,000 km - project car stripped to the bone
1965 Land Rover Series 2a Station Wagon CIS recovery therapy!
1961 Volvo PV544 Bare metal rat rod-ish thing

I'm here to chat about cars and to help others - I'm not here "to always be right" like an internet warrior



Don't leave that there - I'll take it to bits!

I am a total nut case here....but....

I would not go messing with the bands nor internal adjustments until, I corrected the fluid level and inspected all the bushing and linkages...

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Yep, that is what the lock Nut is supposed to do.

Not exactly your particular problem but this is from a Transmission Manual:
No power transmission with Selector lever in position"R", all forward gears in order>
Brake Band B-3 wrongly adjusted
Brake Band B-3 damaged and/or the Band Lining damaged
Free Wheel defective (I don't know what that part is so someone else will have to tell that.)
Working pressure too low or completely absent--Lip Sealing Ring on the Band Brake Piston B-3 damaged.

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84 300D, 82 Volvo 244Gl Diesel

I lost reverse on my 79 300D at one point during my ownership, it would only barely work on level ground. I tried to get at the bolt to adjust the band but couldn't, so I took it to a local mercedes specialist. The charged me $50 to adjust the band for me. After that reverse worked perfectly, nice and strong. Might be worth spending the $50….

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2004 F150 4.6L -My Daily
2007 Volvo XC70 -Wife's Daily
1998 Ford F150 -Rear ended
1989 J-spec 420SEL -passed onto its new keeper
1982 BMW 733i -fixed and traded for the 420SEL
2003 Volvo V70 5 Speed -scrapped
1997 E290 Turbo Diesel Wagon -traded for above
1992 BMW 525i -traded in
1990 Silver 300TE -hated the M103
1985 Grey 380SE Diesel Conversion, 2.47 rear end, ABS -Sold, really should have kept this one
1979 Silver 300D "The Silver Slug" -Sold

From what I can remember reading in the Foum Most of the Band Adjustment Bolts where of the type that Sheard off with you tightend them. Meaning there was no screwdriver slot on what was left of the Bolt.

The meant you either had to cut your own Slot or get another Bolt.

The OP is lucky He has one that has the screwdriver slot.

If it was Me I would spend a lot of time looking for that specific thread and see what it has to say.

I just though of this. It is possible to use a Nut Splitter on the Lock Nut. If you use the Nut Splitter on opposit sides of the Nut you end up with 2 halves of the Nut.
With the Lock Nut gone there is a good chance the Adjustment Screw can be turned. That would allow the OP to make the adjustment and at least see if the making and adjustment is going to fix it or not.
After that is proven He can look for another Lock Nut or a regular Nut with Loctite appled to the Adjustment Screw Threads.

Attached Thumbnails

 

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84 300D, 82 Volvo 244Gl Diesel

Fluid level has been adjusted and is at near perfect level based on the dipstick. Reverse still requires about 3/4 throttle for 2 seconds to fully engage into reverse. Pulling my breaker bar out today to finally get the reverse band adjustment nut loose