Another Q on gearing...

[Darrman]

Ok, I am trying to gather parts for a regear during the christmas holiday, this would be my first attempt.
I have 3.55 opens now, and I want to get 31's soon. This will be the tire size from now on, no bigger. So with a manual trans, should I go with 3.73's, or 4.10's? This is my D.D now, so I need the best of both sides, good torque on takeoff, and decent highway manners. Also I have added around 200 pounds of crap, like brushguard, etc, and I have steel crawler rims, pretty heavy.
Right now its sucks, these gears have no power on takeoff, not hotrod power but just regular getup. I am also debating a change to a limited slip rear, dunno just yet tho.
And if its 4.10's I need, where can I buy the front and rear. I have searched and have only found 4.56's and 5.something front gears. The rears are common, but this reverse rotation is hard to find.
Thanks for any help.

 

[Darrman]

anyone?

 

[dreamr]

4.10

 

[PnyPwr]

I have 3.73s in mine now with 32" tires and it drives like stock!

5 speed 2 door

got them outta a stock automatic explorer

if I could have found them I would have gone with 4.10 or 4.56 but mine is a mostly trail-only rig

 

[sn0border88]

only going to 31's I wouldnt touch the gears, way more money than its worth IMO.

 

[Darrman]

only going to 31's I wouldnt touch the gears, way more money than its worth IMO.

What is the long term consequences of leaving the 3.55's in? Would it burn up the clutch/trans faster?
The reason I am debating this in the first place is mainly for torque, first gear has to be babied already and I am afraid of what the 31's will do to make it worse.

 

[sn0border88]

its a manual trans, I wouldnt worry about it that much.

 

[Darrman]

What about pulling a lightweight trailer, say 2-3k pounds loaded?

 

[sn0border88]

then you prolly would want 4.10's but how often are you panning on towing? If not often, invest in a trans kit instead.

 

[glfredrick]

All things considered, 4.10s were a factory option on the Ranger with smaller diameter tires. It won't be that drastic a change, but it will improve your low end grunt on take-off and while pulling a trailer.

I'd do it in a heartbeat if you are already committed to spending the money. I'd also do it myself at home to save coin. Even if you have to buy a couple of specialty tools you will still win by a long shot over taking it to a shop.

Gear changes are not the rocket science that so many people make them to be. They just take LOTS OF TIME. The time is basically spend in TRIAL AND ERROR fitment to get a good pattern, and it is the same for pros as for amateurs working at home. They just get to charge you $85 + an hour for their mistakes...

You put in a shim, take out a shim, test it to see what it looks like. Sometimes it's good, right out of the box. Sometimes it isn't, and you repeat the process. Do it once or do it 10 times -- same job, just repeat.

 

[92 green sport]

If you have 3:55 right now then a change to 3:73 would not be too different. I have 3:73 and 31's and it is perfect for my now daily driver. at 65 I am a little over 2k rps and I don't even have to downshift to pass. I would recommend the 3:73 but 4:10 if your not on the highway that much.

P.S. I got my front gears from someone on this site. I forget who but I search around and found out that he is the guy to go to. I just wish I could remember his name.

 

[sn0border88]

Shameless plug*

I have a set of d35 3.73s for sale, and the d35/8.8 axles with trac loc rear and 3.73's

See my for sale thread/

They are yours for 200 bucks, more than you'll pay for install alone.

/Shameless Plug

 

[Darrman]

Thanks for the info, I am still debating what to do.
I have a set of 3.73's for the front lined up, but not the rears yet.
Christmas week is the only time of the year I can do any major projects, I would like to do this now if I am going to.
I know I can install the gears, its the shimming that I am worried about, lol
By the way, do I need a install kit for the gear change? My axles are in great shape, almost no wear at all, can I get by with just pinion seals/crush rings being replaced?

 

[sn0border88]

why not just get new everything, its not worth having to tear it all out if something goes bad down the road.

 

[glfredrick]

Thanks for the info, I am still debating what to do.
I have a set of 3.73's for the front lined up, but not the rears yet.
Christmas week is the only time of the year I can do any major projects, I would like to do this now if I am going to.
I know I can install the gears, its the shimming that I am worried about, lol
By the way, do I need a install kit for the gear change? My axles are in great shape, almost no wear at all, can I get by with just pinion seals/crush rings being replaced?

I probably have a set of used 3.73s laying around for the 8.8. Give me a shout if you're interested. I'll sell them for cheap + shipping.

You "might" get away with just the shim kit and crush sleeve, but I'd at least suggest getting a new pinion bearing. That way you can hone out the old one for fitting purposes. You will have to slide the pinion gear on and off several times in the process of setting up the depth, which gets real hard on a bearing (tends to pop the shell off and let all the rollers fall out), so it is best to get the depth set right, then press on the pinion bearing for the final assembly.

I'd probably re-use the carrier bearings if they are in good shape.

Don't worry so much about getting the shims right. It REALLY isn't rocket science at all. Start with EXACTLY what came out of the stock setup for a baseline -- that will likely fit your case just about right. Then check for pattern. If it is off, adjust one direction or the other by subtracting from the side you want to move toward and adding exactly that amount to the other side. Mostly as simple as swapping a shim from side to side. Sometimes you have to use thinner shims to get it just right, hence the need for a shim pack to work with.

Special tools needed:
Dial indicator w/ magnetic base (to check backlash)
Micrometer (to measure shims)
Some means of pulling off and pressing on the pinion bearing (take the pinion to a local shop and give them $5 to do it!)
Dial torque wrench (for checking pre-load -- but you can do it by "feel")
Socket for the pinion nut
Long breaker bar or heavy air gun for crushing the collar

You can get the dial indicator, base, and an adequate micrometer from Harbor Freight for under $40.

http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=895
http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=623

Randy's Ring and Pinion talking about tools:

http://www.ring-pinion.com/content/technicalhelp/default.asp?pid=117

And lots of instructions:

http://www.ring-pinion.com/content/technicalhelp/default.asp?pid=69

Here's one simple article about doing the work:

http://www.differentials.com/install.html

Here's another article by an actual 1st time hobbyist:

http://www.virtual-cafe.com/~wheelin/r&p.html

Another REALLY good article on assembly with home-made tools:

http://gearinstalls.com/gearinstalls1.htm

 

[ExporeRanger]

hope its alright to tag on here real quick..you all seem to really know your gears..i have a 92 4wd xlt with the A4ld auto trans..i have the ifab "cold" air intake system and a flowmaster 40s muffler..i hav no body mods and i hav 31in muds on cragar chrom alloy wheels..(relatively light).. it drives fine now, but i kno i do hav to giv it a lil more to get it moving even on the slightest incline..highway is a mess, it doesnt kno wut gear to be in it seems, and passing is a chore..i dont kno wut i hav in ther now but it cant be that big..i been researchign..and thinkin of goin with somethin around a 4.10..i do drive this car daily..and mot of the time its not on the highway..hoewver..if i cna get it to run better ont he highway..i would def. take it on ther more..i do some minor trail stuff, but nothing too major..i also get 10mpg..
so i'd like to up my mpg, and torque, help out my trans with knowing wut gear to be in and being able to downshift and pass and that sort of thing...
the twist: i do plan to go with a 33in tire around summertime..so i'd like to plan ahead for that as well..those tires would be under the same cicumstnaces except i will be in college, so mpg wont be too big of a deal since i will only be driving it home on the weekends and that sort of thing..so wut gears am i looking at getting? and wher can i get them? i've got the d35 and 8.8 axles..all stock stuf f udner ther
thanks for reading all this and helpin me out..

 

[glfredrick]

I'm currently running 33s with a 4.10 in my 92. It hunts on the highway. I'd much rather have 4.56, and they would not be too much for the 33s.

As I said above, too much emphasis is made on over-gearing. It really isn't that bad. You will not blow up your engine or burn out your gears by over-gearing just a tad.

I just got the latest 4-Wheel Drive Hardware catalog and they have a handy gearing chart. With no overdrive, a 4.56 ratio and 33 tires, the engine rpm at 65 is 3018. With 31s and same setup rpm is 3213. Overdrive will reduce either of those two numbers by around 20% so knock around 600 rpm off either number. Is 200 rpm too much to add to your truck for highway purposes? I'd suggest not...

3.54 with 33 tires - same scenario as above -- 2349. Knock off the 500 (20%) and you are running down the highway at 1850 rpm. WAY too low. You are lugging the engine, out of the power band, and using MORE gas than if you spun it a tad higher.

3.54 with 31 tires -- 2500 rpm. Still too low -- under the recommended scale.

Factory -- 28 tires, 3.73 gears = 2909. 31 tires with 3.73 = 2628, already low on the scale for recommended rpm (which is 2800-3100 across the board for FACTORY - 3100 - 3300 for high performance).

Old-time hot rodders knew that gears were THE CHEAPEST and SAFEST way to increase performance -- UNLESS -- top speed was the goal. Then you need all the RPM you can get, so low gears are the rule, with much added horsepower as you can find.

For example, my 1966 Olds Cutlass, with swapped in 455, pushing around 600 HP with 2.73 gears was topping out around 185 mph (6500 rpm, 28 tire, 2.73 gear, 1:1 trans.). 1/4 mile times were in the mid 13s @ 99. On paper it would run faster (198) but I ran out of power at that speed. 600 HP isn't enough to push a car that heavy and un-aerodynamic any faster than that. My 70 Chevelle, running a 355 pushing 550 hp ran 12.18 @ 118 in the 1/4 and top speed was 155 (7800 rpm, 28 tire, 4.11 gear, 1:1 trans, and enough power to get it there ) That car would wheels-up launch, and bounce again in 2nd. Lots of quickness (0-60 under 3 sec.). Motor spun around 3200 @ 65.

Another for instance... I tow with a Chevy Trailblazer, and have swapped out the stock tires for some that are 31" tall (from 29"). What that does is move the rpm down the scale 200 rpm @ 65, which when towing in 3 (instead of burning up the OD) puts me right in the power band -- as if it was in OD -- while running with load. Works perfect. I pull down 13 mpg with a loaded 'Sploder on a heavy 18' trailer w/camping gear. 3300 rpm gets me 80 mph. Just right.

Most of us will never run our Explorers past 100 -- especially if they are modified with large off-road tires and such. No worries about over-gearing -- especially with OD.

Hope this helps some of you guys figure out your gearing.

 

[ExporeRanger]

wow..thats a lot to swallow..i understood that for the most part and you were very thorough..thanks a lot for the great info. but if i could recap; with my setup and my plans, would i be lookin at 4.10 or 4.56 or another setup?..sounds like your saying 4.56s or so..i've got 31s and am moving to 33s in the summer with about 6in of lift. should i wait till i get 33s to gear? or should i go ahead and "over"gear a bit now..
final verdict?
thanks so much
-chris

 

[FROADER]

Might as well wait until you get the tired to gear.

 

[Darrman]

Thanks for your help, this is exactly what I was looking for, technicals, and figures of different setups.
I am looking for low rpm grunt power, I do not drive much on the highway, but I want to be able to when I need to. What I need is pulling power, and stop and go without riding the clutch power.
Right now at most red light/stop signs, I hav to rev up to around 1200-1400 rpm to take off without shuddering under strain, unless its perfectly flat or downhill slightly.