Want to try 4x4

[Josh B]

Isn't limited slip what makes the front tires grab so much when it's turning?

 

[ericbphoto]

Isn't limited slip what makes the front tires grab so much when it's turning?

Limited slip usually refers to the differential. It helps transfer some power to the wheel (left or right) that has traction, as explained by a few people up above. Limited slip has nothing to do with front/rear bias.

 

[James Morse]

Thanks for all add'l info.
I don't have door sticker I am trying to get it. There is ton of info on that, not in the VIN, like if it had pinstripes and if so what colors.
Yes I want arrangement where winch stays in cargo box but I have a way of attaching it front/rear. Or to start, at least rear, I want to get an AOR bumper with D-rings and I'm unclear whether I mount the winch to this item (below) or if it attaches to a 2" (class 3) hitch.
I actually don't have a towing need right now. What I was thinking was to have a good frame hitch both front and back (and attach winch to that... somehow). But then I was thinking, if the D-rings are sturdy enough to pull on, that means the bumper itself is sturdy and, sturdily mounted, for instance, sturdier bumper mounts. Anyway that would mean if I have a way to mount the winch to the bumper without involving a hitch, then I probably wouldn't do the hitch, but, I could almost for sure do it later because the bumper and hitch are really two different things. Unless it was logical to do them at the same time, but everything costs, so really I could skip the hitch as long as I have a way to safely bumper-mount the winch but I want eventually, I think, to put an AOR front bumper and then I would want to be able to put the winch there as well.
And I thought of a front hitch (for the winch attachment), but I think that's quite a bit harder than a rear hitch, so if I could get away with not doing any hitches that would be great.
If I did ever do towing then I'd probably want the hitches both front/back, I understand the front hitch can be real handy in positioning a trailer.
It sounds like if there are any weak points of the 97 maybe it's the radius arms. Am I correct in saying it is SLA type?
I don't have the torque/hp curve in front of me, but the earlier 4.0L is real torquey. True the later 4.0L has a bit more hp, but not really significantly different torque.
Just judging from the rpms they give respectively for hp and torque (I'd assume these are maximums of course) those are 3000 for torque and 4200 for hp so it seems like that's basically your best power range.
They have to equal at 5250 rpm to to me that would imply after 4200 you are losing both hp and torque.
Here is the winch attachment, how it works exactly I don't know, or if it works for what I want to do.
Champion Speed Mount 2in. Hitch Adapter, Model# C90002 | Northern Tool

 

[Josh B]

Limited slip usually refers to the differential. It helps transfer some power to the wheel (left or right) that has traction, as explained by a few people up above. Limited slip has nothing to do with front/rear bias.

Isn't the front differential a differential?

 

[ericbphoto]

Isn't the front differential a differential?

Yes. I was referring to this statement where you mentioned the front.

Isn't limited slip what makes the front tires grab so much when it's turning?

Your front axle most likely does NOT have limited slip.

 

[Josh B]

It sure does a lot of digging in up there when I'm turning in 4WD, i felt for sure that's what it was.

In fact I am very reluctant to do much turning in 4X4 for that specific reason

 

[Roert42]

It sure does a lot of digging in up there when I'm turning in 4WD, i felt for sure that's what it was.

In fact I am very reluctant to do much turning in 4X4 for that specific reason

Related to the difference in speed between the front and rear axel. The transfer case creates a lock between the front and rear.

An awd car has a type of hydraulic coupler that connects the front and rear differentials, marking it a differential in sorta of its own.

 

[Josh B]

Right, I had to study that for a bit and Eric is Absolutely correct, there Is No limited slip in the front axle, in fact, there is No Slip whatsoever!.

Even when I started digging I started on the wrong page which cleared it up for me. I first went to the Limited Slip Differential (Rear Axle I soon realized) First photo, you can see the Clutches and the Spring, which together provides the limited slip function.

Then after realizing it was the rear axle there, I looked at the front axle and there is nothing that can slip between the Transmission and the wheels, nothing, which yields a direct gear drive with no slip.
Photos 2, 3, and 4 of a Dana 35 8.8 front differential and axles

 

[ericbphoto]

Your Dana 35 front axle is an open differential. It DOES "slip" or allow differential action between left and right sides. I'll see if I can find a video for you to see how that works.

Up above, in post #29, I believe, you list the numbers from a rear axle tag. 3L78 88. If you clean it and look closer, you will see that it really reads 3L73 88. That is a differential with an 8.8" ring gear, 3.73 to 1 gear ratio. The L stands for limited slip. That differential has the clutch packs and it limits or reduces the amount of slip between left and right side when turning or driving on surfaces with varying degrees of traction.

 

[ericbphoto]

In a clutch type limited slip differential, the spring and clutch packs put pressure on the side gears to try to force them to turn together with the carrier and ring gear. More spring pressure = less slip. Some people try to force extra clutch discs or shims in it to increase the pressure. When the friction material in the clutch packs wears out, the effect is reduced until it finally operates as an open differential.

 

[Josh B]

Thanks Eric, that's some interesting stuff

 

[don4331]

Axle tag (rear)
6359F R
3L78 88 7E21

fastpakr said it's 3.73 limited slip 8.8"
I'm sure manual would confirm that (which I didn't have at that time)

that's good, right? I mean, versus not being lsd

ok one might have wanted 4.10 but already had discussion about difficulty to get front gear for this and I don't think it's worth it esp for daily driver
I think 3.73 is fine for what I do and it will also be fine w/ 31" tires.

so front diff would also be limited slip, or no?

Rear differential with 3L73 was limited slip when truck rolled off the line in '97. But 25 years later the clutches (and steels) are probably getting more than a little worn.

And we will note that when clutches and steels wear, the gears in the differential move apart making less than full contact. So, say every tire rotation, it is good to check (with passengers wheel up/driver's down, truck in neutral, if you can spin the wheel by hand, the limited slip is worn out and needs clutches and steel refreshed.

Detroit Locker, isn't a locker, it puts torque to axle with most traction - opposite of most limited slips. It needs a certain amount of difference to operate so is hard on tires on street when they aren't exactly same size i.e. when you replace flat with spare. But the old F-100 would have 3 wheels spinning just before it gave up.

The NP203 transfer case in the K20 back on the farm in my youth was AWD with a differential just like the one in the axle. You could also "cage" it, which locked front and back axles at same speed.

 

[00t444e]

Quite a bit of misinformation on here about how differentials work. An Open differential doesn't send power to one wheel, an open differential is a 50/50 torque split meaning both sides always get the same amount of torque. The problem with that is if one wheel gets in a slick spot or in the air it takes a very small amount of torque to spin that wheel so the wheel that still has traction doesn't get enough torque to turn it since it is receiving the same amount of torque as the slipping wheel. Limited slip differentials use clutches or gears to transfer torque to the wheel that has better traction, however for them to work both wheels have to have some traction, they don't work that well if one wheel is off of the ground for example. A locked differential makes both wheels turn at the same speed regardless of the torque it takes. Also a Detroit locker most certainly is a locker by definition.