m1009 gearing questions

[fourwheelerjeff]

i have an m1009 that i was going to sell, but looks like i may keep it.
if i plan on driving this to the trails every once in a while, on some 36 inch swampers, what would be a good gear ratio?
leave the 3.08's in it for 2012.3 rpm's
put some 3.42's in it for 2234.4 rpm's
put some 3.73's in it for 2436.9 rpm's
put some 4.10's in it for 2678.7 rpm's

thanks
jeff

 

[imiceman44]

i have an m1009 that i was going to sell, but looks like i may keep it.
if i plan on driving this to the trails every once in a while, on some 36 inch swampers, what would be a good gear ratio?
leave the 3.08's in it for 2012.3 rpm's
put some 3.42's in it for 2234.4 rpm's
put some 3.73's in it for 2436.9 rpm's
put some 4.10's in it for 2678.7 rpm's

thanks
jeff

If you have the th400 in front of your 208, I'd say keep the 3.08 for now, see how it goes.
I know the engine will ike the low RPM's at highway speed, you just need o see if it has the pick up and go then you're golden.
I did that with my diesel but I had an SM465 so when i needed more go, I would start in Granny low, but most of the times starting in 2 was jut fine.
And I had 35" tires.

 

[fourwheelerjeff]

yes, i have the turbo 400 and will be driving it to wheel. i was thinking 3.42's might be a good compromise. supposed to look at some axles today that are rebuilt.

 

[jp0863]

i have 4.10's with 35's and it seems a little too low geared for the highway, but works well for foothill's driving. in the mountains on steep grades it just doesnt make enough power to begin with so not sure gearing is as much an issue. when i had the 3.08's and 31's or the 4.10's with 35's it didnt matter... just sloooooow as heck going up grades

 

[imiceman44]

yes, i have the turbo 400 and will be driving it to wheel. i was thinking 3.42's might be a good compromise. supposed to look at some axles today that are rebuilt.

Just as a comparison:
I have a wagoneer with the 360 V8/th400 and 3.54 gears with 35" tires.
It drives fine but I have to shift manually to help it accelerate, the diesel will do better with better low RPM torque, on the highway speeds I never had any problem keeping up with traffic.

 

[fourwheelerjeff]

i have an m1009 that i was going to sell, but looks like i may keep it.
if i plan on driving this to the trails every once in a while, on some 36 inch swampers, what would be a good gear ratio?
leave the 3.08's in it for 2012.3 rpm's
put some 3.42's in it for 2234.4 rpm's
put some 3.73's in it for 2436.9 rpm's
put some 4.10's in it for 2678.7 rpm's

thanks
jeff

i have settled on the 3.73's i believe. tires will be 38 inch swamper radials

 

[rajincajingt]

this is my first post here so please be gentle, but im looking into a CUCV truck for a temporary tow rig. For some good hwy rpms, 60-70mph, you will need some 3.55s, 38.5"??? that sounds crazy to me.

i read that the sweet spot is 1850-2000 for mpg and 2500 for torque, correct?

and just a stupid question, why is that when calculating a gear ratio with an auto vs manual, the rpms are higher in the auto? is the torque converter eating some of that or jsut the tranny itself??

 

[tRustyK5]

If you're planning to tow i'd gear deeper, or go with not such a large tire. If you're not towing and want economy then aim for the 1800-2000 range on the freeway.

Unless the auto has a lock-up convertor the auto will have a little bit of slip even at highway speed. It's usually about 4-6% depending on the torque convertor, tranny, gearing and rpms...

Rene