T20 Adjustment Questions

[budzinsk]

Hi everyone. I got my max together (thanks to so many on this board) and it became clear I did not adjust the T20 correctly. So today I made a set of the tools to adjust it - they are .200 thick. The problem is that when I try and put the tools in , there is very little threads left holding the plunger. When I pull on the stick, the plunger is 1/4 of an inch from coming out of the case. So I can get maybe a 2 or 3 turns of the bolt in the plunger before it is pressing on the tool. Does this seem right? Should I purchase bolts that are maybe a little longer? I cannot imagine I should need to do that.

I did tear the T20 apart, clean, reassemble with new seals, gaskets and bearings... The bands looked like new. Any ideas?

[thebuggyman1]

I'm not sure I understand. The plungers are recessed 1/4" or more into the case when pulled tight? Do the plungers move freely? 2-3 turns sounds like it is too little, but i did have a trans once that I only got 5-6 turns on them. I later found out that some old bands were shorter than others, and when relined, that is what you end up with. I can't think of what you could have done wrong other than if the plungers went too far into the case the O-rings could have popped out the inside of the case. If that happened you need to pull it back apart....your O-rings are probably bad.
Another thing to watch for is the roll pin holding the bands to the plungers....it is easy to scratch the plunger bore if it's not set right.

[budzinsk]

Thanks Jim. Ok, I did some work on it this morning. I got 4 new plunger bolts since the originals were bent. I put them in and adjusted it using the adjusting tool. Here is what is happening. when I push the sticks forward, nothing happens.... When I move them backwards, the max moves forward. All of the plungers move freely and have new O-rings... My unit did not have any sticks when I got it since it was setup by the Army to use as a remote control vehicle. I got the sticks and put everything in per pics on the site, but there is a chance I screwed something up - here are some pics. What I noticed now that I have it adjusted is the upper plungers pull out to be flush with the case, but the bottom ones only come out about 1/4" from the end of the case....

[thebuggyman1]

I don't think you have a trans problem. Sounds more like linkage/controls. How about pictures of the sticks/linkage and the fwd/rev lever and linkage.
The diamond shifters should point forward (rod connection fwd) when in forward. In the picture, you are in nuetral.

[budzinsk]

Thanks Jim. Wow, this could be a stupid driver error on my part. Here are some more pics:

[budzinsk]

Do you think I may have the diamond shifters in on the wrong side?

[Mike]

Do you think I may have the diamond shifters in on the wrong side?

You could. Since it only takes a minute, pull the diamond shifters out and try to manually move the shift collars into the forward position. Do that by placing a screwdriver in the hole that the diamond shifter is in and catching the groove on the shift collar meant for the pin on the diamond shifter. Carefully leverage it to get it to move being careful not to scar the hole or collar. Then see if it operates correctly.

[thebuggyman1]

The linkages and sticks look to be correct.
The diamond shifters have a pin that is offset. If they are in the wrong side they will not engage the shift collar(s).
I bet this is your problem.

[budzinsk]

Thanks guys. I thought that was it (and was a little worried I screwed up the pin in the diamond shifter), but both sides were fine. What I noticed is that when I have it in reverse, I need to push the sticks forward to go in reverse. When I have it in forward, I need to pull the sticks back to go. There is very little turning capability in either motion. I have a feeling I reversed something when I resealed the trani... I am out of options but to rip it back apart. Here are some more pics if it helps....

[thebuggyman1]

In the last 2 pictures, the trans is in reverse. If you put it back in neutral, and you pull a diamond shifter, the pin will be towards the front of the machine.
There's nothing inside to put in backwards and cause this issue. The planetary/ring gear set up cause the 2 drums (each side) to spin in opposite directions. You tighten a band on one drum to force the other one to spin at full power (essentially a differential w/o spider gears). The shift collar determines if that drum or the stopped drum is connected to the output sprocket.

[amphibious drew]

Is the engine running backwards?

[budzinsk]

Thanks guys. I really appreciate the help. Ok, I took the passenger side diamond shifter out, while it was in neutral and the pin is facing forward - see snapshot below. I looked through my pics of the T20 from when I took it apart and came to the same conclusion that I do not think I could have put anything back together that would cause this behavior. Also, my engine is turning clockwise when I look at the flywheel side - I assume this is correct? I put a red arrow in the pic below to show the direction the driven clutch is turning.. Any other ideas? I am stumped....

[thebuggyman1]

I'm all out of Ideas too Rob. EXCEPT
There is a real expert on all things amphib....and he lives close to you. I think around an hour and a half?????
Even if his schedule is busy, he has 2 sons that I bet they got their fathers abilities. I hate to volunteer someone else, so hopefully he can chime in here himself.

[budzinsk]

Thanks Jim. I appreciate it. Is it possible to put the bands in backwards? What I mean is put the plunger in the wrong hole in the case?

[amphibious drew]

No the bands cannot go it backwards. Did this t20 come with this machine? Is it possible the gov had the opposite holes of the diamond shifter drilled out and plugged the original holes? The t-20 could the be set in upside down. Does this make sense to anyone else? Would it cause the issue described? I just can't figure out how the input shaft is in the right spot if that were the case though.