Slipping in reverse.
 

One more, the tranny on the 81 SD does a little clickity, clickity thing when backing up and if you accelerate aggresively it will slip in reverse. Forward gears seem fine, no noise, slipping, nothing.

Two questions:
1. Is this a sign that this tranny is heading south quickly?
2. If I service it might I lose the tranny altogether?

The fluid hasn't been changed in probably 15 years and smells really, really bad!

Well, I say 1st try changed the tranny fluid. Do it gradually meaning don't just drain it out and change it. The new fluid has to mix with some of the old. So change a little the 1st time than in like 3-5 days or so do it again. If it's not that might be the reverse gear. On my 77' 300D the gear was shot. Because when I was younger I would just put it in reverse and hit the gas without letting it shift properly. So the gear just wore away. One day me and my friend went to Burger King and had to put it in reverse than push the car back to get it out of the parking space. Good luck!

Oh by the way. We had the tranny redone when the reverse gear went.

If the problem is only on reverse gear, definitively you have a problem on the B3 piston. It works stopping the planetary gear that makes the car goes reverse.

If the problem is on the B3 piston, it has a cheap fix, but it will take you hours. The problem often is that the o-rings of the piston are worn, and this produces the non-effective stopping of the planetary.

Any other possibility is that the B3 rubber brake band is worn. This fix is very expensive, because the gearbox has to be dismanteled. Sometimes, you can fix the play of the B3 rubber brake band acting onto a bolt that acts on it, but this is not recommended if you don´t know exactaly the torque and some more information.

Good luck.

(sorry for my poor english)

I think Leathermang would say try some Trans-X. :D I really don't think it could hurt anything.... changing the fluid might help too.

The reverse band need to be adjusted it is located on the passenger side of the car in front of the transmission the only way to adjust it is by cutting a notch in the screw and turning the screw in, then back off 1 ½ turns.

Changed the fluids, result is...
 

No more clicking noises when backing up but on a steep hill it will not move the car. If I goose it the tranny will also slip in reverse.
One other thing I noticed is that when I take my foot off the accelerator in reverse the car seems to freewheel as the motor and tranny do not work together to slow the car in reverse.

Any thoughts?

After the change the transmission sure seems to shift better and now that the clicking is gone I feel a little better. Just need to make sure and not travel down any steep hills that I can't turn around at the bottom...;)

Is this a trans-X candidate?

"smells really, really bad!"
Yes, just changing fluid does not cause the old varnish in those little holes to be dissolved and flushed out.... be sure to look at the total capacity of the trans... and read the instructions... on my wagon it took two quarts to meet the instructions... give it several hundred miles before taking it out... although I see nothing wrong with having it in there... would not leave the first application of it in there due to the desire to get the dissolved varnish OUT of the transmission completely... and of course change the filter at that time also....

Vuncan,

You English is just fine, better than some from the USA.

P E H

Haiges, thanks for your encourage.

This forum is also an exercise to practise the english language :)

Best regards.

Manuel.