2nd Gen Non-Engine/Transmission 4.10's vs. 3.73's

[biggy238]

This has been weighing on my mind the last week or so. I ran the percentage of difference in circumference of the 254/75 vs. my 35's and I came up with 4. 06 as the ratio I would need to mechanically make my truck return to stock rpm's and shift points. (this was with absolute diameter rather than loaded diameter or rev's per mile)



A 4. 10 would be less than 1% difference from a 4. 06.



Should I return my truck to it's original driveline ratio's or should I comprimise with 3. 73's.



I'm absolutely tired of no acceleration on hills and pitiful acceleration in general.



Tell me what you guys think aboout power vs. mileage with the 35's and 4. 10's

 

[Vaughn MacKenzie]

Biggy if you plan on 35s long-term I think your Auto would be most happy with 4. 10s. It depends on how much highway driving you do I guess, but unless you're doing a lot of road trips I would lean toward the 4. 10 gears.



Is there a 3. 73 available for the Dana axles or are you thinking of swapping out to an American Axle from a 3rd Gen truck?



Vaughn

 

[edgrim]

To Have More Power

I switched from 3. 54 to 4. 10s before putting the #10 plate in and 4GSK, I wish I'd have gone with 3. 73 instead, with the extra power I don't really need the 4. 10s anymore. That said I think you would love your current set-up if you added a plate and spring kit, should be cheaper than swapping gears as well.



Don't forget to do timing as well.

 

[CATCRACKER]

this is easy



stock power auto 35's 4. 10 or



beefed up transmission #90 more hp 3. 73's



35's with 3. 55 is like 3. 23 to low

35's with 3. 73 is like 3. 40 or s/m perfect you must have more power though

 

[ASTAR]

Vaughn, stock 2nd gens have 3. 54's or 4. 10's





I had 3. 54's with 35's, 36's, and 38's. I liked them a lot but I was going to hurt my new transmission towing with 38's so i dropped back down to 35's. I didn't like the look of 35's anymore (being used to the 38's) so I went to 4. 10's and 37's. Everything is happy now. If you plan on doing a built transmission or you don't tow heavy, I would suggest adding a little more power and keeping the 3. 54's. If you do tow and don't plan on getting a built transmission, your transmission will be a lot happier with 4. 10's. It would be really easy to recoup the lost power from the bigger tires and leave the stock gears.

If you decide to go with gears, I posted something in the classified section asking if anyone wanted to trade (some people that have stock 4. 10's and stock tires hate the high RPM's going down the freeway). I got a few replies and the one that I swapped with lived a couple hundred miles away and had an almost identical truck and we just met up and swapped complete axles! It worked out to be very cheap and easy to do.

Just something to consider.

 

[biggy238]

Astar: I read some posts about the swap but I can't ditcht he front now because it's mostly new. It wouldn't be economical. The tires are also a mainstay.



To the others: I'm fairly certain I saw 3. 73's listed for the d70. Maybe it was wishful thinking.



I plan to bomb this truck this summer but i'm having serious issues with my 15-17 mpg. I'll have a 60 mile per day (probably more like 100 with cruising and chore time added in) commute for school, with 10-10% grades on the way. I've located a DTT installer but I was looking at the gear swap as a holdover until the bombs drop. I pulled 23mpg out of these tires one time and not since. I think the transmission is getting weaker but I can't deal with it at the moment.



Will just the power upgrades compensate for the gearing in the long run? More power= more fuel+more air. More fuel = $$$ If you all think it's more advisable, i'll make due until the transmission money comes along. Good things come in time I guess. As long as fuel costs come down in the meantime.