I think my tranny is going out and it is causing me to think about what is the cause of it. It only has 85,000 miles on it and unless the previous owner is lying it has only been used to pull a boat across Iowa. Not exactly hard work. The truck also gets terrible mileage. I was wondering if changing to a lower gear would help my tranny last longer next time as well as helping my mileage. Right now my truck has the stock 3.55 gears in it and 265/75/16 tires. I would love to lift the truck up a bit and put some bigger tires on it, but I think the tranny rebuild is going to push that off a bit. What do you guys suggest for a good gear ratio? I don't do a lot of pulling, I haul a trailer of wood every now and then and maybe a trailer of some ATV's. If I upgraded tires I would like 33" or 35" at most. Also, I was wondering if it would be easier/cheaper just to throw some 3/4 ton differentials under the truck?

 

4.10s for 33s
4.56s for 35s

ill be running my 4.10s with my 35s here soon, because im not feeling a 1k regear job

 

Wow $1K for a gear swap?? I guess front and rear add up, but that seem like a lot! I would also be thinking about adding either a posi unit or a locker in the rear. Does anyone have any suggestions on what way to go there? I don't do a lot of muddling, but I HATE it when I put it in 4X4 and only 2 wheels spin!

 

Take a look at some Detroit Lockers, they are pretty cheap compared to ARB and they get the job done.

 

Gears, lockers, labor approx $2000 or more, Dl will cost $600 each or more, gears about $250-400 each set, install kits $140 each set, expect the truck to be in the shop for 8hrs. No ARB or E-Trac for the 9 1/4 rear but yes for the Dana 44 front. A Eaton Dl are not for the average street truck, I have them front and rear and they take there toll on parts and me. Eaton makes some good posi and lockers check them out. As for the 3/4 route diffs I see priced from $125 each to $700 each, then add, new wheels, new drive-shafts and moving the spring perches and still re-gear and add locker or posi units.

 

I have 33's and 4.56 are perfect...! I don't drive the truck over 65mph much though. If you do a lot of highway driving your gas mileage will suffer. I would have been disappointed with 4.10's. The 4.56 gears really get you off the line. I spent $1200 for the regear and then another $350.00 for the locker. That same locker normally costs around $500, i got a good deal on mine.

 

For the best fuel mileage, try to match the effective ratio of effective stock ratio. The right gear with the right tire. 33" tire - 3.92 gears, 35" tire- 4.11 gears. I still get 13 mpg running a 295/70/17 (33.4") with 3.92 gears. Great on the highway, 72mph @ 2000 rpm, with plenty of passing power left. Either way, get the tranny fixed first, changing gears will only prolong the Inevitable.

 

Thanks for all the input!
Yeah I know re-gearing now would be worthless really. I am just not wanting to spend all this money on a tranny and have it go out again. I thought that a steeper gear might help, as I think 3.55 is WAY too high for a truck. Although they are better than the 3.42's in my old Chevy.

 

I have a set of used 3.92 gears I will get ride of cheap, back gears will bolt right in, front you would need a new m/t carrier for the 3.92.