If you have the typical rubber drive disc and aluminum wheel transmission, you should be able to adjust the position of drive disc by adjusting the linkage. The closer to the center of the aluminum drive disc, the slower the speed in that gear.

Empty the gas tank, stand the unit on its front end, remove the cover under the bottom and look at the tranny.

Thanks Baymee , yes it is the rubber drive disc and aluminum wheel type. I was just wondering if the differential type could be adjusted to a very slow drive speed.

You can adjust your system to creep like an ant in first gear.

I don't know of any other way to adjust the speeds than to adjust the linkage and position of the friction wheel upon the drive disc.

Thanks again Baymee , its good to know that it is possible to adjust to a very slow speed. I adjusted it and it is slower. I will look at it closer when it warms up.