need a different trans

We have been looking at transmissions to use in our tractor. We cannot use manual/cluth setups, MUST be auto with converter. To achieve the gearing we desire, we need a trans with a low gear that is between 3 and 3.5:1 and allows an upshift into a 2.5:1. A 545 allison is 3.45(1st) then 2.25 (2nd) which is just to fast. It is not economically feasible to change rear end gears, and we cannot have supplemental gear boxes. We make <500h.p. maybe 600 ftlbs, max 6000rpm. Tractor weighs 5500 with driver.
Does anyone know of a trans with a ratio like this? Or have ideas that might be of help ? Heck, can a C6 be built to achieve these ratio's?
Perry

New Ford 6 speed automatic? Not sure how economical they are over getting new rear gears.....

Could you use something like a LencoDrive or Lenco/Bruno set up?

Ford Mustang 5R55S should be
1st- 3.25
2nd- 2.44
3rd- 1.55
4th- 1.00
5th- .75

Although some sources list different ratios...

I'll do some reading and see what I can learn about them. We don't break C6 trans as it is, just need the diff ratio's. I'll need to find out about how it will stand up under our conditions, etc.
Thanks for the direction!
Perry

I got a 44 Massey rear I could lend you. It would fix your issue You won't break it.
In all honesty I thought I had the answer for you but I read your post about your rules and my idea was out

get you a Bruno and put a Lenco behind it that way you have a converter and can row the sticks.....I am pretty sure they will get you any ratio you want....

One downside with a Bruno/Lenco combo is they will chew up some power. One good point is on each gear change the Lenco can be shifted softer/harder depending on how you adjust each section's shifter tower height.

DILLIGASDAVE wrote:One downside with a Bruno/Lenco combo is they will chew up some power. One good point is on each gear change the Lenco can be shifted softer/harder depending on how you adjust each section's shifter tower height.

The Bruno /Lenco doesn't eat that much. My old dragster only went .02 faster after I changed to a 'glide and that was probably from the 30 lb weight difference

Might be a door car vs dragster thing.

On a nitrous door car I worked on swapping back & forth between a Bruno/Lenco 3 spd vs a 'glide, the glide was always around a tenth quicker & about 3 mph faster than the B/L. The B/L did however have a slight advantage in the first 60ft, probably from the steeper 1st gear.

I am bound by rules to an "automotive" trans so no good on Bruno-Lenco set up. I don't have any strength /durability problems w the C6, just need to shift up to about a 2.5:1 to come out a little bit harder. The 2.5 gives me all the tire speed our combo can pull.
Thanks again
Perry