3:54 or 4:10's for 35" tires? looking for best fuel milage

[San Felipe Bob]

I have 3:54's

My rear end has 180k miles and is ready for a rebuild.

I have a chance to buy 4:10's with limited slip. So I'm weighing the option's.



My truck weigh's 7700 lbs. plus the 20' toy box once a month.



Thanks for your idea's.



SFB

 

[EricBu12]

3. 54 gears and tall tires do the best. I have 3. 54 and 285/75-16 AT tires. When on the flat, my truck with a shell weighs at 8000# and I get about 20-22 on flat ground. A 35" tire might have to get a little faster to get the same revs at about 70 or so to get the good milage.

 

[Cooker]

3. 54's with 35's and a tight torque convertor might be a little doggy out of the hole for everyday driving and your in town MPG's may suffer because of it, but the highway MPG's should be pretty good with that setup.



Personally with an auto and 35" tires I would go with 4. 10's, but I do a fair amount of city driving.

 

[San Felipe Bob]

I guess I should have stated .

I drive 60 to 70 % stop and go freeway traffic in Southern California.

Sounds like 410's may be the better choice?



thanks

SFB

 

[jponder]

Originally posted by San Felipe Bob

I guess I should have stated .

I drive 60 to 70 % stop and go freeway traffic in Southern California.

Sounds like 410's may be the better choice?



thanks

SFB

Yeah with the auto you might be right. If you had a 6 speed I would say always get the 3. 54. If 6th is too tall for your needs you got 5 more to choose freom

 

[Cooker]

Originally posted by San Felipe Bob

stop and go freeway traffic in Southern California.

That statement seems wierd. It doesn't seem like stop and go and freeway should be in the same sentence



SFB, I would think the 4. 10's are a better choice for your driving.

 

[dlange]

You will want the 4. 10s.

 

[Jim S]

Just read your post searching for tires. Just one thing about your 4. 10 gearing if it's not too late. Your sig says your a 4x4 and you probably already know this but your going to have to change the front diff also.

 

[NVR FNSH]

I have 4. 10s, 6 spd and 35s - best mpg to date is 17mpg at 2000 rpm/66mph unloaded on I-5 from Sacramento to Portland. With my 36ft 5th wheel the 4. 10s are great. Unloaded I'm looking for 7th gear.



With the HP you're running you might be okay with 3. 54s and the automatic. Heck, give it a shot and then swap gears if you need to. Just curious, why does the rear end need to be rebuilt?



Brian

 

[bighammer]

Originally posted by Cooker

That statement seems wierd. It doesn't seem like stop and go and freeway should be in the same sentence

It's CALIFORNIA freeway driving.

 

[bighammer]

Originally posted by Cooker

That statement seems wierd. It doesn't seem like stop and go and freeway should be in the same sentence

It's CALIFORNIA freeway driving.

 

[Chipstien]

I have a DTT transmission and 35" tires. I could not imagine running that setup with 3. 55. I have 4. 10 gears and would'nt have it any other way. Get the 4. 10 gears..... better for towing too.