4.56 gears vs. 4.88 gears for 33's

[shawn.m]

4.88's

I would say go with 4.88 and plan on 35's very soon

as we are in the same local -- it will mean the difference of going to strawberry trail or barret jeep trail.

On my last trip to barret jeep trail I was really wishing for more gear.
the 4.0 5mod 4.10 and 33's did not let me creep enough in 1st gear. used the clutch a lot more than I wanted.

on 5.13's and local rock use
the local guys in my club have talked about the jeep guys breaking the 5.13 ring and pinions in the rocks. They break when they hop on the rocks from too much throttle. It goes back to driving style

 

[canyoncritter]

3000 rpm, will be aprx 68 mph with 4.88 and 33's 5th gear

3000 rpm will be aprx 72 mph wiht 4.56's and 33's 5th gear

3000 rpm will be aprx 74 with 4.88 and 35's

4.0L 5spd 4.56's and 33 tend to net me aprx 17 mpg mixed driving.


if you have 33's 3.73's and the 5spd ,3rd gear (1.31 ratio) and driving at 58-60 mph is what 33's and 4.88's will be like in 4th gear. (3000 rpm)


so if you want to see if deep gearing is for you to daily drive etc, drive your truck in 3rd gear on the free way for 20 miles doing 60mph.(3000rpm) dont use your spedo, use your tach for this test.

 

[CHKNFKR]

Keep the 3.73s and build a doubler. You'll have good highway economy (and you'll be able to hear youself think) and you'll have LL for rocks, trails, stump pulling, etc...

 

[4x4junkie]

3.73s and 33s will not in the least bit be conducive to good highway economy.

 

[-Nathan-]

Keep the 3.73s and build a doubler. You'll have good highway economy (and you'll be able to hear youself think) and you'll have LL for rocks, trails, stump pulling, etc...

fail.

I had 33s and 3.73s with a healthy 4.0, and averaged 15 mpg, 5th gear was useless and did not feel powerful. I switched to 4.56 gears, had a TON more power, and averaged close to 18 mpg.

 

[wahlstrom1]

Yup, 33's and 3.73's sucked worse then 4.56's and 37's. 4.88's/33-35" FTW!

 

[legoms013]

Epic. Fail.


I'll tell you right now, that 3.73's and 33's sucks bad! Thats what I am currently running so why would I keep them?

I get between 14.5 and 15.9 mpg. And freeway driving is a gutless endeavor.

"Rolls eyes"

BTW I am having a disc 8.8 being regeared 4.88's as we speak.

 

[mhughes165]

even with more gear you will still only net about 18mpg, my not so great running at the time 5.0 bronco2 with 3.73's and 33 was actually allowing me to get above 20 mpg consistent in town but not much better on the highway aslong as i was stayin out of the skinny(which is difficult)

theres all sorts of different ways to get the same result you wanted, and they all cost about the same lol

but either way for stock components to have that better use of the power you have the 4.88's were the smart move, and when u make that jump to 35's u wont be kicking yourself for not doing the gearing

but hey, i also just finished a 1991 exploder 4.0 fm145 with 3.73's and 33's and he is aswell getting consistently over 20 mpg.

in the future if you just dont have enough umph just get 4 cyl guts and slap them in your m50d and it will be like u went with the 5.13's

 

[Yellowsplash]

I guess I can chime in with some experience as I went from 33s and 3.73s to 33s and 4.88s...

Do the 4.88s and never look back. Plain and simple. Especially if your gonna upgrade to 35s.

I built an Explorer 8.8 with Yukon 4.88s and a Powertrax No-Slip. One of my favorite mods to the truck thus far. Driving for years on 33s and 3.73s was just annoying. I live in a hilly mountainous area where the tall gears caused me to lug up hills constantly and I found myself switching from redlining 2nd to lugging in 3rd, and on the interstate 5th gear was only good for flat and downhill...once you hit a hill you had to downshift and floor 4th to maintain speed and sometimes even down to 3rd and redline the thing to maintain highway speeds. Gas milage was horrible at around 12-13 mpg.

Now after the switch to 4.88 I am averaging 18 to almost 20 mpg easy, and I have soo much more power to get around in the hills...I actually enjoy driving my truck that much more than before. Even though it is geared alittle low with the 33s, its a blast to drive. Having the power to overcome hills without having to downshift all the time and actually having the available torque is great. At highway speeds it does run slightly higher rpms, but lets face it, do we really need to run 80mph down the highway with 6-8" of lift and big ass tires? 65-70mph is plenty, and I dont mind doing it while getting decent gas milage while Im at it.

Dont fall in to the myth of guys saying your gas milage will suffer because your crusing at or slightly above 2500. There are more factors that will affect this assumption such as geographical area and whether or not it is flat or mountainour terrain, type of roads and highways, amount of time spent on each, driving style, etc. In my situation, lugging the engine and trying to overcome the tall gears was killing my milage and putting unnecessary strain on my drivetrain. Having the extra torque and a closer gear ratio between gears allowed the drivetrain to struggle less to get to speed which uses less fuel. While a taller gear might be great for kansas, if your in the colorado rockies you'll want that extra bit of gear the 4.88 will provide you.

Good Luck with the build and do it right while you have it apart. You'll be glad you did later on.

 

[michowski]

I got 3.73 and just 2 days ago installed some 33's and honestly its not as bad as I thought it would be. Highest I will go is 4.56. Mainly street driven and there is honestly no need to drag race my lifted ranger so i'm not worried about 0-60 times.

 

[legoms013]

You can always go up a gear (until your on the hwy) but you can't get a lower gear you don't have. I'd go 4.88's over 5.13's as I don't believe the D35 is capable of holding a tire that 5.13's require as mentioned a couple posts ago unless it's a crawl only wheeler.

There is a limited selection of gearing available for RBV's, short of an atlas or doubler (which will cause much more stress then lower axle gears) the lower gearing is required in our trucks as the tranny gearing SUCKS (3.40/3.72 first gears for manuals)!

problem with some people is that they dont have actual experience with gearsets. If I took a truck, and swapped out 3.73 to 4.10, and the owner wasnt told, guaranteed they could BARELY tell the difference. My point is that unless youve regeared, and know what parasitic drag and everything else does to affect they way your truck ACTUALLY feels and works with a different gearset, GTFO. Comparing numbers youve read off the interwebz means jack $hit.

Go 4.88 legoms13, youll have a much better wheeling experience, and feel like it really wakes up your truck, makes it exciting again.

I ran 33's for a little while with my 4.88s and loved it with the 5r55e auto. the truck ran 65-70mph down the freeway in overdrive as opposed to having to run like you said up around 75-77mph to get to the point where it will stay in OD without shifting a ton. And it crawled like crazy and fuel mileage increased to as weird as it sounds but I think that was due to not working the motor so hard. Then I got a deal on 35's and still love the gears it still crawls really nice and can turn the tires on rock and mud. thats just my experience with them

Good post. Though I don't disagree about the gear strength thing, one thing that needs to be taken into consideration is the fact most of the axle's other components (shafts, u-joints, etc.) tend to be weaker than even a 5.13:1 R&P set, so I don't see gearset breakage as something to really worry too much about (D30s OTOH have some issues with deep gears, but they also have a 3/8" smaller ring, as well as a smaller pinion shaft dia. too, which leads to more gear deflection). I've yet to see anyone who's broken a 5.13 D35 gearset and shown pictures of it, though I've seen plenty of broken shafts lol.

Also, your tires typically will slip long before the torque on your shafts ever could reach 38,000 ft-lbs. Though an exception might be is if your tire gets caught against an undercut rock ledge and wedges itself in there (or if you're on the throttle hard and bouncing, the shockload from which is what typically breaks stuff).



Legoms, What i would probably say is go ahead with whatever your gut tells you, be it 4.88 or 5.13, as either one will be a thousand worlds better than your 3.73s (FWIW, with the 5.13s and your auto's 0.75:1 OD, you should be turning around 2550 RPM @ 65 if my math is right (2400RPM w/35s)).
If you DO find yourself breaking stuff, you could always sell those axles and upgrade to something like a D60 (a locked D35 & 8.8 with good gears in it should not be hard to find a buyer for).
I think a D60 might be a bit excessive though if you're always one to pick your line and crawl it, rather than blast up stuff with a bunch of throttle.

A few guys here have ran 37s and even 38s on these axles and managed some decently long periods without issue doing some fairly decent rock trails. Though again it IS all in how you drive. You get too crazy with the skinny pedal and like said, things are bound to break.



BTW HS, You''l absolutely love the 4.0L clutch upgrade. The stock 8-7/8" clutch sucks donkey nuts, which is about all I can say about it.

Yup, 33's and 3.73's sucked worse then 4.56's and 37's. 4.88's/33-35" FTW!

I guess I can chime in with some experience as I went from 33s and 3.73s to 33s and 4.88s...

Do the 4.88s and never look back. Plain and simple. Especially if your gonna upgrade to 35s.

I built an Explorer 8.8 with Yukon 4.88s and a Powertrax No-Slip. One of my favorite mods to the truck thus far. Driving for years on 33s and 3.73s was just annoying. I live in a hilly mountainous area where the tall gears caused me to lug up hills constantly and I found myself switching from redlining 2nd to lugging in 3rd, and on the interstate 5th gear was only good for flat and downhill...once you hit a hill you had to downshift and floor 4th to maintain speed and sometimes even down to 3rd and redline the thing to maintain highway speeds. Gas milage was horrible at around 12-13 mpg.

Now after the switch to 4.88 I am averaging 18 to almost 20 mpg easy, and I have soo much more power to get around in the hills...I actually enjoy driving my truck that much more than before. Even though it is geared alittle low with the 33s, its a blast to drive. Having the power to overcome hills without having to downshift all the time and actually having the available torque is great. At highway speeds it does run slightly higher rpms, but lets face it, do we really need to run 80mph down the highway with 6-8" of lift and big ass tires? 65-70mph is plenty, and I dont mind doing it while getting decent gas milage while Im at it.

Dont fall in to the myth of guys saying your gas milage will suffer because your crusing at or slightly above 2500. There are more factors that will affect this assumption such as geographical area and whether or not it is flat or mountainour terrain, type of roads and highways, amount of time spent on each, driving style, etc. In my situation, lugging the engine and trying to overcome the tall gears was killing my milage and putting unnecessary strain on my drivetrain. Having the extra torque and a closer gear ratio between gears allowed the drivetrain to struggle less to get to speed which uses less fuel. While a taller gear might be great for kansas, if your in the colorado rockies you'll want that extra bit of gear the 4.88 will provide you.

Good Luck with the build and do it right while you have it apart. You'll be glad you did later on.

Here are some of the great experience based suggestions from forum members responding to my original thread question, with the most useful information concerning real world experience per say. Some I may have forgotten to quote, needless to say I still appreciate everyone's great input.

Thanks again, check my build thread in a few weeks, and the 8.8 will be under my truck. I plan to get the D35 regeared 4.88's by the end of July.

I'll let everyone know what I think once the regear, and swap is done. Though I have no question that you guys lead me correctly for my situation.

 

[Eagle_Scout2002]

Here is a fun calculator to play with. I have been looking through it quite a bit on my other build and am now playing with it on my Ranger. http://www.grimmjeeper.com/gears.html


Ray