Anyone have any information on being able to change the gear ratioes in the Allison? When doing serious towing, I find 4th and 5th gear are too far apart. Sometimes I don't like to be in either one, but would prefer somewhere in between. Actually, another gear between 4th and 5th would be ideal, but I know that won't happen. Could the ratioes be changed such that 4th is a little closer to 5th, say 0.8 or 0.85:1 and then, push 3rd up closer to 1:1?

Thanks,

The 2000 is .74 in OD

What tires are you running? If you are not having troubles starting out, you might be able to go a little taller and make 4'th comfortable.

Running 265R16E's. Generally, no problem starting out.

I would suggest a Gear Vendor overdrive, if you want to spend some money. It is 22%, and you can use it in all gears, and shift on the go.

anyone know what the reverse gear ratio is?

Allison 1000 gear ratios...

First: 3.10
Second: 1.81
Third: 1.41
Fourth: 1.00
Fifth: 0.71
Reverse: 4.49

For serious pulling "Gear Vendors Overdrive" John

I got in touch with Gear Vendors, hoping to get an overdrive for my Kodiak - they tell me that they have nothing to fit behind the Allison 1000. US Gear do not either. Apparently the Allison is controlled with fibre optics, that neither manufacturer can interface with. That is really annoying - hopefully they will figure it all out sometime - I also need more ratios.

Mylash

Someone on here said something about an Eaton 100 2 speed rear. That may be the way to go. I wouldn't think it would cost any more than the Gear Vendor, even if the GV was an option.

I have not been able to find out anything about 2 speed rears that would be of a benefit to either a pickup or a medium duty. Most are 2 speed underdrives, not overdrives, and the one that is cannot fit a pickup, and probably not a medium duty either. I would really love to get some kind of overdrive unit, to improve my towing mileage.

mylash

This would be alot of work, but if nothing will bolt in, you may need to use something such as a Browning. This is a 3 speed trans mounted midship, with a driveshaft in and out. They can be mounted backwards also. Typically, they are two unders and a direct, but backwards it would be two overs. I saw one in a pickup years ago. Don't know how common they are anymore, they were used in medium duty trucks.