Experience w/ 3:55 gears & 31x10.5

[donkey boy]

I don't need the theories about gearing and tires, Thanks guys
I would like to hear about the actual experience some of you might have with this set-up. I'm not so much worried about acceleration. It's a SOHC so it has some torque. What I'm worried about is the car being able to tackle some climbs on & off road without burning up the tranny.

 

[Ray Lobato]

Hi Michael,
I have a 97XLT with 3.55's and 31 inch tires. It will work, however I must tell you that I just had the tranny rebuilt, after 109000 miles, and I do take it off road. Now did this combination cause the tranny to go out? I really don't know. What I can tell you is that it will shift out of OD more going up hills. On off roading I didn't have any problems getting up hills as long as I had traction. I get 18 miles to the gallon and at 65MPH I am around 1800-2000rpm. I can't remember, but it is low. The only thing I can tell you is if you are going up hills or in the mountians, take it out of OD. There is some loss of power, but not enough to keep me from getting up the hard stuff. I will soon be changing gears as I am going to be running 35's after the Trailmaster lift comes in. Hope this helps. Oh. It was the torque converter that went out on it. I opted to get the whole thing rebuilt since I had 109k on it.

 

[donkey boy]

Thanks Ray

I read in your other thread about your bad luck, it really would have been nice of your tranny to wait to fail until you were back home I needed to smile about your comment regarding the stuffed animals; this somehow sounds very familiar to me. (Why is it, that always the biggest of all 3000 and something stuffed beasts in the house need to come along for a trip?)

Anyhow, I think 109 kmiles is not bad. With your opinion, you supported me in my decision to go for 31x10.5. The current 235's (Good-Year) still have some life left, so I will not change before this fall.

Again, I really appreciate for your imput.

 

[Guerilla Biscuits]

Are 3.55 stock gearing?

 

[donkey boy]

Yup!
Axle code 45, what unluckily also means "unlimited slip diferential" (= open dif.)

[Edited by donkey boy on 07-11-2000 at 03:58 PM]

 

[FMExplorer]

Where can I find if my 3.27's are open or Limited Slip - and what's the diff between L/S and Posi?

JonM

 

[donkey boy]

Jon, if your axle code just has numbers, it's a open dif. If it also has letters, its limited. I've heard that the codes are listed in the owners manual, unluckily, I don't have one yet, but my dealer ordered one for me (FOR FREE )

 

[FMExplorer]

Thanks - that means I have code 41 (3.27 open). But is there a difference between limited slip and posi?

 

[Goober]

limited slip allow the axles to 'slip' when going around turns and is 'supposed' to engage both sides when one wheel losses traction.
A posi (positive traction), has the axles turning together all the time. So, if you were going around a sharp corner you'd hear the wheels screaching because the wheel are turning at the same rate, but one wheel is turning faster than the other(hope that made sense).
If you have the rear of a vehicle on jackstands and turn one tire- limited slip (tires turn in opposite directions), posi (tires turn in same direction)... I think that's right?
This is my understanding of the difference of the two. If I have forgotten anything or is not quite correct, someone kick me,...I mean someone fill in the mistakes.
Hope this helps you.

 

[FMExplorer]

Ok Goob's,
Now I am a bit confused...
What is the difference between Posi and a hard locker? I have 3.73's with posi sitting in my garage waiting for me to get off my but and install. At this point, I feel posi will be enough considering the amount of offroading I do. Besides - there are very few rocks in Ft Myers (other than curbs) So if I have posi in the rear and l/s in the front (if possible) I should be in decent shape - right???

Thanks

J

 

[Goober]

Jon, As far as I know, posi/lockers are about the same. Posi delivers the power to both wheels at the same rate, if lockers do the same, then they do basically the same job. (Drawing on my military days)..I drove a 5 ton truck on a too frequent basis, I know it had a straight axle in the rear, but I'm not sure about what it had in the front. I believe it was an air locker, (You'd slide a switch that engaged the front axle). Since the military has their own mechanics, we were limited to the stuff they'd let us tinker with.
I have the l/s 3.73 in my truck now. I have played around enough to see the parallel tire marks to see that they are still working well. So until they go out or until I need (TH 2001, Moab,..?), I'll stick with this set-up.
I don't know if this has helped at all. If not ask Rick, Matt, or some of the others who may be able to give you a better understanding of the differences.
Jeff

 

[FMExplorer]

Goober,
I found out a bit more from Brett Grooms - here is what I figured out...
Posi and limtied slip are similar - they both operate with a clutch mechanism. However, posi will turn both tires as opposed to transferring power when one is slipping. A true locker doesn't use a clutch assembly - it basically connects the two axle shafts so they will always turn together at the same rate - with no slippage. This means (I think) that posi - although it will turn both sides equally - can still slip because it uses a clutch where a locker will not slip unless it breaks... Right Matt?? (I've seen a few of the Moab stories...)

So - I am still going to go with the 3.73's and rebuilding the posi because I have the stuff (won't cost anything else)

JonM

 

[swak6287]

so what are u guys saying? 3.55 gears is ok for 31"x10.5" or better go with 30"x9.5". do u know if the tire store can gimme some money for the factory tires?

 

[Char]

donkeyboy, the code for your axles should also be on the driver's side door.

 

[ex91]

i ran a 91 4dr 4x4 with 31x10.5x15 the rest was stock and it work fine and i have 3.55 gears and i found they halp in pulling(like a logg tuck out of a a ditch in winter , and i was told that an explorer couldn't pull much)all i can say is i love my 91 explorer allmost as most as much as i love mysleff(hehehaha)

 

[donkey boy]

Char, yes, the code is in the door, I know. But there is no translation there of what the code actually means. This is what comes in the manual, as I was told. Sorry for not being clear

 

[Goober]

If anyone needs to translate an axle code, I searched and found this site, I think it belongs to one of the members.. http://www.users.uswest.net/~ntrpriz/Axle.htm

 

[Guerilla Biscuits]

The member is ntrpriz.

 

[GJarrett]

Let's clear a few things up

I'm trying to go on a "posting diet", and you people keep pulling me in . I think we need to clear up some misconceptions. I need a woman to tell me that I talk way too much on topics I'm stupid about, but since she's not around, here goes. Ignore at your leisure.

"Posi-traction" is merely a trademark term for "limited slip"; we're just talking semantics here. A "locker" is always going to be called a "locker".

Posi, limited slip differential(LSD), whatever the name; they are relative applications of the same differential engagement type, and both will spin the same way if you jack the rear up and spin one wheel. They are clutch activated and use clutch plate pressure force to transfer power to both tires, though they may differ in amount of positive engagement according to different circumstances.

A locker of any kind will lock the two sides and create a solid axle during times of positive engagement. They will not slip. This is not the same as either posi or LSD.

With a stock Trac-Loc LSD in your 4wd Explorer you can do things that will shock you. A locker will up the ante, giving you the ability to tackle trails that threaten body damage. It all depends on how far you are interested in taking this hobby. I must interject here that capable tires make a huge difference once you get to this level of activity and are as important as the rest of your setup.

SO:
swak6287, the bigger tires are fine. I've seen Ray in action and you certainly won't have any problems.

JonM, you got it; posi and LSD are similar and clutch driven, lockers are locked. However, most have release mechanizisms for operation on hard surface so you won't break an axle when you turn a corner on the street.

Goober, posi and lockers are not the same. Posi is LSD, lockers are lockers.

Donkey Boy, to answer your original question; like I said, I've seen Ray in action. He's done some really fun things with the same gearing/tire setup you are asking about. Your vehicle is capable of duplicating Ray's feats. None of us can say whether the offroading contributed to his tranny problems or not. At his mileage, CA traffic could have done the same thing. If you want to play and try this sport out, I say go for it. I know I'm having a great time.

Hope I didn't offend anyone, and helped someone!

[Edited by GJarrett on 07-19-2000 at 05:51 AM]

 

[donkey boy]

Gerald, I'm happy your "diet" is over and you are sharing your profound knowledge with us . As I said, I will be going with the 31's, but there is still some life left in the 235's that the car came with and it's a pitty to dump them now.

In addition to what you have said, to my knowledge, ALL lockers can be disengaged, have a release mechnizisme. Otherwise, you would not need to spend all this money for a locker, but you simply could weld the right parts in your open diff together and you have it locked for eternity But this is absolutely not recommended to do because highly dangerous!!

I agree with you that you can do amazing things with lockers and LSDs. Future mods could include a limited slip for the rear axle (lucky guys who have one factory fitted, something I was not thinking about when buying my used '97; I could smack me now for that).

Lockers are great, but they also can be dangearous. They are great as long as you are tackling obstacles, where you often have one (or two, but in the diagonal of the car, not the same side please) wheels in the air. But they also can be extremely dangerous, because with the locks engaged, your car basicly wants to go straight. Also in slippery conditions, your turning radius is A LOT bigger with the lockers engaged, what could cause some surprising moments when driving on a twisty mountain trail with a some hundred feet drop at the edge of the street, or when trying to find a way around some trees. So you really need to know, when to use lockers and most of all, when not to use them.