1998 Max IV T20 problems/carb adjustments

[johnj]

Hello everyone,

I am having trouble with my 1998 Max IV tranny. After reading some I see that there is a lot of knowledge here and I need some. I just bought this machine and I knew it had problems but I wanted one and I am willing to put in the wrench time.
When I put it in reverse and pull back on the right handle nothing moves. The left handle makes the left side spin but the right does nothing. I checked and the sticks seem to move back about the same distance. Everything works fine in forward. I am wondering if it is the same band on the right side for forward and reverse or are there different ones. I am pretty sure the bands need adjusted. But if it works in forward would being far out of adjustment really cause that one side to do nothing? I couldn't get to the top of the slide rails to measure them but the bottom rails on both sides are almost an inch from the tranny housing. That is with the springs still connected and I didn't pry them out. I read that they should have about 5/16" of travel when the springs are removed and they are pried out with a screw driver since I don't have the adjustment tool. I also saw how the linkage for forward/reverse went to both sides of the tranny I wonder if it is possible that the left side is moving to reverse but the right side isn't getting all of the way back into reverse. The linkages don't look bent in any way. When I pull back on the right side it almost sounds like it is still in nuetral it doesn't squeel the engine just revs and nothing. I also checked the fluid level which is ok. I am going to take the engine off today along with the platform it sets on so I can get to the tranny and try to adjust the bands. Any help would be appreciated. I have never had one of these apart so I am nervous to tear the tranny apart and not be able to get it back together. I can usually put anything back together I am just worried when I pull it apart gears will fall out and I will not know where they go. Are there any shops in S.C. that work on these? Also does anyone know the setting for the fuel mixture screw on the side of the carb? mine is running too rich and when I leaned it out the motor would bog down on hills and the wheels wouldn't spin it just stopped and I had to roll back down. Even with the motor at full throttle when I got half way up a steep hill it would bog down and stop.
I am also curious I thought the smallest motor they put on these was a 18hp vanguard but mine has a 16hp, also the metal plate riveted to the front has Max II on it but it is a four seater and doesn't look modified. Thanks again for the help.

[thebuggyman1]

Check the pins on your diamond shifters....it sounds like you may not be in reverse.
The T-20 is incredibly simple when you get inside of it. I bet if you can figure out how to pull it then you won't have a problem rebuilding one.

[Mike]

There are different bands for forward and reverse. Like buggyman mentioned though, start by checking the pin in your diamond shifter for that side. Once you remove the plate that holds the diamond shifter down, they will just pull out and you can inspect the pin. As a side note, there is a complete rebuild article for the T20 in the how-to section of the site with step by step instructions and pictures on what to do.

For the motor, you most likely just need to clean the carburetor out. They often get trash in the carb causing them to run like you described. The 16HP motor was a factory option. As for the plate, do you have a picture of it? It should say Max IV. What is the serial number stamped into that plate?

[johnj]

I checked the diamond shifted and it is ok and it was in the groove. the linkage had a slight bend, which I fixed. But I am still having the same problem. I measured the channels when pried out and they are almost an inch that can't be right so I need to know the thickness of the spacer tool so I can make one. I am going to clean my carb today. How far should your sticks move when pulled back?

[johnj]

Another question I read that u should be able to push your sticks forward mine are all the way forward now and the springs are tightened all the way down which has the bottom plungers pulled all the way out. Is guards right or should the channels be straight up and down? Also when u pry out the top of a channel what should the measurement from the housing to the back of the channel be? I think this is the problem. I read the post about having 5/16" of travel but they just said the two measurements should be equal on the top and bottom. When I pull back on my stick the bottom plunger pushes in and the top one comes out. The channel is away from the housing in the middle so the rocking back and forth of the channel doesn't work very well. If I can figure out the measurement from the housing to the back of the channel when pulled out then I can adjust it better.

[Mike]

Most Max ATVs have springs on the laterals that hold them forward. Often though, during steep uphill climbs, the pressure of the springs is not enough to keep the transmission fully engaged. This is why it is good practice to get used to pushing the sticks forward.

There is no measurement for how far away the channel should be from the housing. This will vary depending on the wear of your bands and therefore be different for every machine. Just adjust the plungers until you have equal measurements on top and bottom. Then, run the bolts into the plunger equal amounts top and bottom until you get the 5/16" of travel. You don't have to have the adjustment tool to do this.

This post explains it really well: http://www.6x6world.com/forums/trans....html#post2322

[johnj]

I adjusted the bands tonight. I measured the left side since it seems to be working fine and adjusted the right side to the same measurements. I now have the 5/16" of travel. I haven't put the motor back on yet to try it and I have been thinking about just taking the tranny completely out and opening it up to look at the bands and gears. I read another post and the guy had the same problems as me and one of his gears inside had all of the teeth broken off. I am just getting tired of tearing down and putting back together lol. Do you know the price of a rebuild kit? or maybe what richard's relics would charge if I sent it to them for a rebuild. I would rather just have all new parts in the tranny and not have any more problems. If it is alot cheaper to do myself I will try that.

[Mike]

It would be a lot cheaper to do it yourself. It is very simple. The worst part is adjusting the bands. I'm kidding, even that is much more simple when the T20 is out of the 6x6. It really is a simple rebuild. The rebuild kit include seals, orings, washers, etc and it is very cheap. I think it was around $50. You can buy it direct from the manufacturer Amphibious Six-Wheel Drive All-Terrain Vehicles: MaxATVs - Call 1-800-255-2511 or your local Max dealer. There is a picture of what is included in the T20 Rebuild Article

While you are in there you might as well plan on replacing the main bearings too. If they ever go out on you, you will have to completely tear the transmission back down to replace them. They are pretty expensive for bearings and you have to purchase them from the manufacturer or a dealer because they are custom ground down just for that application.

Other than that, unless something is broken that is all you have to replace. If your bands are showing signs of failure (missing material in places) then you can just have them relined. You can get all four relined for what you would pay for one new band.

Just something to think about. Of course, if nothing is wrong with your T20, I would just change the fluid at regular increments and run it like it is.

[racerone3]

That was me with the stripped gears If that's what you are facing, you will have to replace the drum. That can get pricey. If no major parts are damaged, a rebuild can be done in the $200- $250 range using relined bands (not from Richards), common seals from any good bearing house, O-Rings from the plumbing dept at any hardware store, and main case seals from Recreative. you can also buy a seal kit from them. the output bearings can only be obtained from Recreative as they are a custom ground bearing. The small needle bearing for the input shaft can also be bought from any good bearing house. In the next few weeks, I will be sending a set of bands out to get relined by "Transmission Crafters" and will post my thoughts on them once they come back (I've never used them), but first I need to tear the trany down and see if it is as beat as the rest of the machine was!
If you get your trany torn down, and run into trouble getting it back together just post here and someone will get you pointed in the right direction

[johnj]

Thank you for the help. I am going to pull the tranny today and try to get it apart. This way I will know what is wrong. Where is the best place to have the bands re-lined?