Ugh gear ratio decisions, help me out

[94Jo]

i have been doing some reading about gears lately, since I want to swap axles with better gears. I read pages and pages of threads where guys were sorry they didnt go to lower (numerically higher) gears. Then i read an entire other thread where I think at least two people switched BACK to 3.73 after having 4.10. I was thinking that I want to make my truck not work hard and considering a lot of stop and go that I might as well go to 4.10 gears from a second gen. to give me more "umph" from stops and not stress out the engine and trans. Im no speed demon and rarely go 65+ My biggest tire in my forseable (sp) future is approx. 30-31.4Inches I believe. Now i am at 3.27 and I dont like it. Too high a gear for a truck this size i think, the measly 4.slo doesnt have the torque to really get it moving in OD and stop and go. i have even seen people use 3.27 and up to 33's and not mind it so much, but I can see how. Can anyone offer some insight? I wanted to pick up at least a rear today but I am concerned about what the results will be, if anyone has done this exact thing before, that would be awesome, share which setup you liked, i suck at decision making (probably since i am sooooo cheap so every money choice is a big one) thanks in advance.

 

[James909]

I swapped in 3.73's to replace the 3.27 gears I had in order to increase towing capacity. Before when in overdrive it would accelerate very slow and it felt like the truck was working very hard to maintain speed going up even the slightest incline on the highway. The truck feels like it doesn't have to work nearly as hard anymore and acceleration in overdrive as well as from a dead stop is significantly improved IMO. If you don't do a lot of highway driving you may want to consider 4.10's, although I think that the difference between 3.73's and 4.10's will be minimal. I decided on 3.73's because my commute to school has a decent amount of highway time and I thought that with 4.10's the rpms would be a little high for my liking. Do you have 4x4? The 4.10's are easy to find in second gen axles however it's difficult to find a D35 with 4.10's which is one of the reasons I got 3.73's. Also 4.10's may be more expensive because they are more rare.

 

[94Jo]

awesome to hear, I take the highway to work each and every night so i was a little concerned with 4.10's because of that. I was worried though that after going through all the work of getting the new axle and swapping it by myself that the change from 3.27 to 3.73 wouldnt be worth it. did you swap it yourself? Are you perfectly satisfied? Was the work worth it to still stay in the "3's" The OD struggling is exactly what i was reffering to, i know what you mean about the super slow acceleration, and on long trips with inclines i had to floor it to not be ran off the road by traffic.

 

[James909]

I am very happy with the 3.73's and would pick them again if I could do it over. 4.10's seemed like a little much for a DD. Keep in mind though that I am running stock tires. If you're planning on running 31" tires you may want to go with 4.10's. I did swap the rear by myself which took about a day and a half at a very leisurely pace. Swapping the front differential is a little more involved so I went to my friend's shop and he helped me. Also, make sure you swap in a rear end with disc brakes. It will make the brakes much more powerful.

 

[94Jo]

What part took the longest, i was hoping I could knock it out in a day (as in wake up early and get to it and finishing in the evening) Can you feel the difference in power? I drive like a grandpa because of gas prices but would like a little more off the line umph without worrying about how hard my truck is working. I still cant make up my mind!!! I can get the 3.73 for a hundred bucks, but it wont be disc, or I can wait it out for 4.10 and not be afraid of stuffing meatier tires under the navajo, but risk not finding a front 4.10 for quite some time (which means no 4x4 till i find it). decisions decisions

 

[James909]

I really don't think that you will have a problem doing it in one day. I think I could have but I didn't work the whole day and I took a lot of breaks. There isn't really one part that took the longest, but I may have been lucky because I didn't have any frozen bolts or anything that I couldn't get off. During normal stop and go driving I don't really feel a difference in power unless I get on it so don't expect it to suddenly feel like there's a V8 under the hood. Although it takes off a little bit faster in first gear. There is a noticeable difference accelerating on the highway though, probably because the engine is turning about 250 more rpm. There is definitely more power though because I can feel it when I'm pulling the boat. IMHO if you are planning on running oversize tires I would go with the 4.10's because then it would be about equal to 3.73's and stock tires. Also honestly I think you should get a rear end with disc brakes since you will be going through all this trouble anyway. Trust me you will be glad you did.

 

[HahnsB2]

Rear axle swap will take me about 2 hours. If you're going to run 31s get 4.10s, if you're keeping stock tires get 3.73s. The problem becomes finding a 4.10 D35. The only trucks that have them are 90-92 ranger 4cyl 4x4s, and possibly some 2.9 auto 4x4s and STXs of those years. Anything 93-97 with 4.10s will be a D35 hybrid. There will be a very noticeable difference in acceleration.

 

[scrapper]

Hi, I found a rear end in a 86 or so ranger it is limited slip, the door panel said it was a f4. I think it is a 4.10. I am going to have a shop install it. I was wondering if will run okay with a 2.3 and 225 tires? I do about 20 miles a day highway driving is this going to be a problem? I need to tow a trailer hunting and other small jobs. It currently has 3.08 gears. I just found out that it is only 3.45 gears. I still probly need 373 according to my owners manual, to tow? I have waited a long time to find a limited slip, I can find regular 373 all day long?What now!

 

[HahnsB2]

Hi, I found a rear end in a 86 or so ranger it is limited slip, the door panel said it was a f4. I think it is a 4.10. I am going to have a shop install it. I was wondering if will run okay with a 2.3 and 225 tires? I do about 20 miles a day highway driving is this going to be a problem? I need to tow a trailer hunting and other small jobs. It currently has 3.08 gears. I just found out that it is only 3.45 gears. I still probly need 373 according to my owners manual, to tow? I have waited a long time to find a limited slip, I can find regular 373 all day long?What now!

My fathers 4x4 2.3 ranger has 4.10s with 235/75/15s and it's just right, it think you'll be fine with 225s, assuming that's on 15" wheels.

 

[seth247]

truck has 3.73's from the factory and 31" tires and it works great for me.

 

[scrapper]

Well, I went with the 410 limited slip. I like it, 400.00 to install.Beyond my abilities. The only draw back is 1st to 2nd gear is short. It drives okay. I need to change ,I think it is a gear in the trans? The speedo shows 80 and I am going 65mph. I am thinking about puting a electric fan in it out of a mustang with the same engine in it. It will help add power to the engine, I think? I am not sure how to hook it up. The sensor part of it anyhow. I am thinking of taking the radiator, condenser, fan and installing them in my ranger,going to install factory air someday? I am only running 225 14 wranglers. I am not sure 15 will fit under the front. I would like to lift front to same hight as rear, I think it will be to much cost. I think 15 would fit ok then.

 

[Kona]

My 91 Super Cab 4X4 XLT came stock with 215-75-15 tires... you should be able to fit 235 -75- 15s as that is what my wifes 91 Scab STX 4X4 has on right now. If you have a 4X4 you do have to match the front and rear gears before you use 4 wheel drive. I have 3.73's and 31" Big O X/T s and I sure wish I had 4.10's or higher gears, having driven my truck on its winter tires (235 75 15 ice radials ) I know exactly how much power I have lost.

 

[jumpn4jesus]

THis guy has D35 4.10.

 

[HahnsB2]

THis guy has D35 4.10.

Wrong gears for a TTB D35...

 

[jumpn4jesus]

Wrong gears for a TTB D35...

Oh, I didn't know that. Sorry.

 

[XploreAlaska]

A ÷ B • C = X

A= old tire size
B= new tire size
C= old gear ratio (current)
X= new gear ratio (to gear it similar to stock)

 

[1993fordexploere]

i have 33's and 3.73's and with my kkm and all my other little minor mods(mostly kkm) i have plenty of power still

 

[Jack Flash]

A ÷ B • C = X

A= old tire size
B= new tire size
C= old gear ratio (current)
X= new gear ratio (to gear it similar to stock)

sorry, it's the old school teacher in me.....

A(30") ÷ B(33") • C(3.08) = X(2.98) ,,,,doesn't seem right ?

should it be :

B(33") ÷ A(30") • C(3.08) = X(3.38)

.
.

 

[Kona]

i have 33's and 3.73's and with my kkm and all my other little minor mods(mostly kkm) i have plenty of power still

I guess you don't need much to mallcrawl, I was just doing some heavy duty wheeling and if I am not in 4 low forget about getting enough rpm to work with unless you also get a pile of speed up too! I don't mean to sound offensive but the Ford v6 does not have anything if you are under 1500 rpm unless you are in 4 low. Any real hill , or a need to idle along up rough terrain needs gears to maintain engine speed. Even in 4 low it would be nice to have a little more grunt (3.73 w/31's )

 

[1993fordexploere]

I guess you don't need much to mallcrawl, I was just doing some heavy duty wheeling and if I am not in 4 low forget about getting enough rpm to work with unless you also get a pile of speed up too! I don't mean to sound offensive but the Ford v6 does not have anything if you are under 1500 rpm unless you are in 4 low. Any real hill , or a need to idle along up rough terrain needs gears to maintain engine speed. Even in 4 low it would be nice to have a little more grunt (3.73 w/31's )

um man. my brother has one almost exactely like mine only lifted a little higher. and he took his to rubicon 4 times and to moab once with auto transmission and 3.73 gears with 33's and did perfectly fine and still had power.