T-20 Band Lining

[Eldon]

My Max II has 379 hours, I would like to think rather easy hours when compared to some amphibian events. About 150 hours or so have been tracking in the snow and while harder running than wheels on firm ground I don't believe it was unduly stressed. A forum member recently advised me that it was possible that around 400 hours that the bands should be replaced or re-lined and that an indicator was by measuring how far the plungers will protrude out of the case with 1/8" being considered plenty. My plungers protrude 1/4" + though as yet I have not actually measured. I was advised if I didn't replace the linings in time it could ruin the big bucks drums so of course I am concerned. I would appreciate input on this scenario if possible. The transmission seems to work OK though I believe it doesn't have the pull of confidence it did when I got it.

[Mike]

Have you tried adjusting your bands yet? I would start by adjusting them and see if the steering action improves back to what it was originally (instructions on how to do this can be found in the how-to section under the T20 rebuild thread or by searching this forum). If that doesn't help, really the only way to tell if the bands are worn is to split the case open and measure the thickness of the bands with a set of calipers or micrometer. There are a couple of threads here in the transmission forum that will tell you what the thickness should be if you use the search. While a plunger that sticks way out of the case is a sign that something is wrong, I wouldn't let one that protrudes slightly make you think that you have to reline the bands.

[Eldon]

I have adjusted over the past few years if it got to where it didn't steer like I thought it should. It is steering quite OK and works good. The transmission has never been abused or actually even used harshly in the short term. Running tracks in snow is the hardest work it has done. I have religiously changed the fluid and additive. The transmission has groaned on rare occasion under a brief heavy task while turning but as a rule it is quiet. I would be surprised if under normal usage it would need to be opened and serviced in under 400 hours. All this said when the time comes I hope to become proficient at overhauling the T-20 if I can achieve this then I believe I can run the Max nearly forever as I have a pretty good handle on the rest of the machine. I have played with motorcycles,old tractors,cars and newer cars for decades and the T-20 drive system I believe to be an absolutely fascinating system. When I have made adjustments,though I didn't have the tool,I did follow the instructions as found on the forum. I am taking the tracks off this weekend for the season and re-installing the front drive chains,while I am in that area I will check the adjustment and measure all plungers top and bottom as to how far they come out of the case. I really appreciate the advice Mike,Thanks.

[Eldon]

My transmission appears to be in adjustment and I think is working OK,perhaps a groan once in a while in reverse if under heavy load but not common. As I was checking the adjustment I noted the top plungers protrude at full engagement about 1/4" and the lower plungers protrude about 1/8",same on both sides. Is there a cause for concern here? Reverse typically is what tips me off to needing adjustment. If I am interpreting the layout correctly the transmission has 4 bands the upper plungers are for revverse and the lower for forward.