Gears for the AAM axles

[BigDaddyMC]

Just got off the phone with an AAM representitive that did some leg-work for me.



I have the 11. 5 rear end and the 9. 25 front end.



The news was mixed. They are going to release a 4:56 front (9. 25) gear set any day now, however nothing is even close to being ready for the rear end. Only options to date for the AAM is the 3:73 and the 4:10.



Many have asked the question on the 35" BFG's/Hummer wheel set up as it relates to pulling power and differences between them and the stock setup. Many haven't had the chance as winter was still handing around.



I just pulled my toy box full of quads and supplies. I go about 9500lbs, and let me tell you..... we need the new gears BAD!



I probably lost close to 10mph going up the same grade, and lost about 2 - 4mpg. I was only able to get about 275 miles out of a tank. You do the math..... that's about 8mpg. Same run, same load, I got was getting about 360 miles out of a tank.



Empty my milage dropped about 1. 4mpg. I drive mostly express ways and just a little city. Probably about 90/10. I was at about 17mpg empty, now about 15. 5.



I have kept my stockers, and will be putting them on for pulling until the gears are tooled and put on the market. I don't think that the 4:10's will be enough, not pulling heavy anyway.



my2cents



Sorry - I have 3:73's now. Looking desperately for the 4:56's

 

[Bertram65]

The difference between the 3. 73 and the 4. 10 gears is about 9%. The difference between the 265/70/17 and 315/70/17 tires is about 8%. I do not know what kind of impact the reciprocating mass has on power, but from a straight gearing persepctive you should be right back to where you where with the 3. 73s if you change out to the 4. 10s. I think someone on either here or the DTR swapped axles with someone looking for 4. 10s.

 

[BigDaddyMC]

Interesting and SIMPLE way to look at it. Maybe I should have done the math first. Looking at it that way, I might be real nice. I really wanted something in the 4:30 area, but that will probably never happen. As far as the recipricating mass thing goes, I'm not sure how that effects real world towing. I do know that BRAKING was also affected. Definitely something that you can feel. I'll look into the 4:10 thing, and maybe get lucky trading someone.



Anybody else have thoughts on the 3:73 - 4:10's???



Thanks for the imput - next time I'll do the math first





I'm kind of slow... ... ... .

 

[Bertram65]

I am planning on going to 265/70/19. 5 which are about the same height as the 315/70/17. I want to get my RPMs down on the highway below 2K when travelling.

 

[BigDaddyMC]

guess you don't pull anything heavy... . would that be a good assumption?



I'm trying to find some 4:10's as I type... . I have't got the dealer price back yet, but I'm usually pretty close to Shop Price. Hope it doesn't hurt too much.

 

[Greg Boardman-RIP]

Originally posted by BigDaddyMC

Just got off the phone with an AAM representitive that did some leg-work for me.



I have the 11. 5 rear end and the 9. 25 front end.



The news was mixed. They are going to release a 4:56 front (9. 25) gear set any day now, however nothing is even close to being ready for the rear end. Only options to date for the AAM is the 3:73 and the 4:10.



Many have asked the question on the 35" BFG's/Hummer wheel set up as it relates to pulling power and differences between them and the stock setup. Many haven't had the chance as winter was still handing around.



I just pulled my toy box full of quads and supplies. I go about 9500lbs, and let me tell you..... we need the new gears BAD!



I probably lost close to 10mph going up the same grade, and lost about 2 - 4mpg. I was only able to get about 275 miles out of a tank. You do the math..... that's about 8mpg. Same run, same load, I got was getting about 360 miles out of a tank.



Empty my milage dropped about 1. 4mpg. I drive mostly express ways and just a little city. Probably about 90/10. I was at about 17mpg empty, now about 15. 5.



I have kept my stockers, and will be putting them on for pulling until the gears are tooled and put on the market. I don't think that the 4:10's will be enough, not pulling heavy anyway.



my2cents



Sorry - I have 3:73's now. Looking desperately for the 4:56's

I just went from 235 17 drw to 315 70 17 bfg srw. I have noticet a great increase in milage. 2. 5 around town and 5+ on the HWY. I used to turn 2500 rpm's at 65 mph. Now I turn 2000 rpm's at same speed. Towing hasn't really changed much. I towed 12,000 lbs yesterday and mileage was up 2. 5 mpg. 4. 10's are great for me. I couldn't be happier. I used to never believe the guys who said they would see 20 mpg. On my last tank I saw 19. 93 mpg over 450 miles.

 

[BigDaddyMC]

I don't get it... . You went from a DRW to a SRW???? You have the 4:10's now and went to essentially a 3:73. At least that's what the math is saying (around there anyway). I'm sure that you went up. I'm extremely happy with the 3:73's performance with my stock tires. It was a dream. I think that with the change to the Hummer wheels, the resulting final drive puts me in the same neighborhood as 3:42's. Just to high of a gear.



I still haven't got the costs of 4:10's. Waiting for my phone call.

 

[Greg Boardman-RIP]

Big daddy,

You Got It Man,



I went from a DRW 3500 with 235/75/17's and converted it to a single rear wheel truck with stock rims and 315/70/17 BFG at's via H2. I have 4. 10 gears on my truck and with the 235's it was sad how poor my mileage was. Now the 315's net me better milage and ride alot better too. With the 4. 10's I run at or about the same as 3. 73's if you add on the tire.



Greg