Jeep Wrangler Forum banner

1 - 20 of 33 Posts

·
Registered
Joined
·
60 Posts
Discussion Starter #1
Have a 2001 TJ with open diffs. Wondering about putting a trutrac LSD in one axle for up coming winter. What are your thoughts? Any one that has experience with one? Will it make my Jeep much better in the snow...better than regular 4H or 4L?

And any other options you guys know of/have used for winter driving. Just bought the TJ after having a 2015 Rubicon so worried about winter driving this year. Is 4x4 in the open diff TJ pretty good by itself for basic snow driving? Don't do any real off roading so don't think I need a full locking diff...? Just want a daily driver that can handle Oregon winters.
Thanks,
Mark
 

·
Registered
Joined
·
1,138 Posts
LSD help with traction in 4H, (3 wheels engaged) and will add fishtailing in 2H.
I would opt for a locking diff instead of LSD.
 

·
Registered
Joined
·
421 Posts
I had a TJ with Truetracs front and rear in CO winters. For self described regular winter driving, locked diffs are asking for trouble.

The number 1 thing to do is a set of real snow tires. Number 2 would be careful use of 4 high. Number 3 would be LSDs. The gap between 1 and the rest is huge.

Motive power takes a back seat to stopping and road handling in the winter, I'm sure you know as an experienced winter driver. Tires have an effect on all 3, 4wd and LSDs only on motive. While it's a hassle to struggle getting moving, that pales to losing control on curves or at intersections.

So, given $1000 to spend, DM-V2s or some other winter tires. Open vs TTs is a smaller difference. You'll break traction with either setup in 2wd rather easily most of the time on packed roads. Hence judicious use of 4 high. 4 hi engaged when accelerating away, and off as much as possible otherwise. You'll notice some break away on curves in 4 hi as the lack of differentiation causes slippage as the bind needs to be relieved. Even then it's not common, as natural slipping is always occurring, but on a sharp bend it can happen. Mitigated to a degree by what should be low speed in winter, but something to be aware of. I had replaced the t-case linkage with the cable setup, so shifting 2wd to 4wd was a breeze. If I had the linkage, the constant shift on the fly would have been a headache.

Normal road scenarios, not offroad we're talking. Given my setup, with snows and f&r TTs, the TJ was a beast in the winter. I doubt I could ever get stuck and had total confidence when venturing out. From regular road to blasting through drifts.
 

·
Registered
Joined
·
14,211 Posts
Although a rear limited slip can help much more bang for the buck with real snow tires for driving snowy roads

And selectable lockers are both a non issue unlocked and can help get out of ditch after snowy slide
Auto lockers are not preferred for snow driving
The TJ rubi rear has both limited slip and a selectable locker which is nice for snow unlocked and stuck in ditch locked


Sent from my iPhone using Tapatalk
 

·
Registered
Joined
·
748 Posts
I had a Truetrac in the rear of my JKU and it was great in Michigan snow. I plan to put one front and rear of my JLU.
 

·
Registered
Joined
·
1,273 Posts
Trutrac. Best option for TJ in the snow. Had front and rear in my TJ. The 2wd handling will be as good as open/open 4wd in most circumstances, and in 4wd its great, even woth just a rear one. The TT is a superior lsd that does not react as poorly IMO in snow as others. But that is just my opinion having run open/open here in NH for years before installing them, so take it with a grain of salt.

Sent from my SM-G975U using Tapatalk
 

·
Premium Member
Joined
·
11 Posts
I have Trutracs front and rear as I sometimes drive 30 miles through snow to and from work. They work great for me, usually don'r need 4 wheel.
 

·
Registered
Joined
·
607 Posts
For a daily, just rear traction, if you want to climb slopes. Even a lot of the latest "all-wheel drive" cars are not able to climb gentle slopes.


I guess the question is whether a ratcheting locker such as a Powertrax Lock-Right is still more susceptible to fishtailing than a TT? I don't doubt it, just wondering how many people have tried both?
 

·
Registered
Joined
·
1,138 Posts
That's only an issue with a clutch-based LSD like the Tracloc, it's not a problem with the gear-based Truetrac.
I thought LSD is only clutch based where the clutch alows "slippage".
Gear based in my understanding is Auto-Lock differential even though it acts like LSD there is no "slip" occuring.
 

·
Registered
Joined
·
14,211 Posts
The old first generation 300zx had two types lsd
Low end was clutch and those wore out

High end was viscous those did not wear out and had cooling fins

On the video posted gotta be skeptical when only the Subaru’s get up the hill in a Subaru video


Sent from my iPhone using Tapatalk
 

·
Knows a couple things...
Joined
·
48,981 Posts
I thought LSD is only clutch based where the clutch allows "slippage".
Gear based in my understanding is Auto-Lock differential even though it acts like LSD there is no "slip" occuring.
That's not how LSDs work. A LSD can be either clutch or torsion/gear-based. Both work by coupling the spinning tire with less traction to the other tire with the most traction to increase the resistance seen by the engine which causes the engine to put out more torque. That gives more torque to the tire with the most traction which is often enough to get you going again. Engines but out zero to very little torque when it's not seeing any resistance/load to work into. Increase that resistance the engine sees and its torque output raises which is how the tire with the most traction receives more torque. How that happens can, again, be done with both clutch or gear based (aka torsion) LSDs.

Here's an article I wrote probably 15 years ago that explains how it works... 4x4 & Torque answers - JeepForum.com It's somewhere on this forum too but I can't find it since this forum's recent major layout change.
 

·
Registered
Joined
·
607 Posts
Thanks Jerry, excellent as always. If TT does not have fishtailing, can the same be said about a Powertrax No-Slip?

The snow hill video is more entertaining, but I can appreciate the viewer doesn't see what they're working with, so here's a less entertaining but more scientific rendering of the same on rollers.

There are a lot of roller videos on flat ground, where any vehicle can get over eventually. The differentiator is when the rollers are on an incline. Then only Subaru can climb the hill, because they're programmed to be more proactive about sending power to the rear wheels.


Ryan at Driving Sports TV has had several videos about this, and notes even the highly touted 19 Rav4 and 20 Highlander are still not up to Subaru's programming (around 4:00 - 7:00 into the video).


The following includes a lifted-wheel video that's very telling. The lifted wheel is not spinning at all because Subaru's version of brake-lock differential is keeping the lifted wheel fully braked.

 

·
Registered
Joined
·
1,138 Posts
That's not how LSDs work. A LSD can be either clutch or torsion/gear-based. Both work by coupling the spinning tire with less traction to the other tire with the most traction to increase the resistance seen by the engine which causes the engine to put out more torque. That gives more torque to the tire with the most traction which is often enough to get you going again. Engines but out zero to very little torque when it's not seeing any resistance/load to work into. Increase that resistance the engine sees and its torque output raises which is how the tire with the most traction receives more torque. How that happens can, again, be done with both clutch or gear based (aka torsion) LSDs.

Here's an article I wrote probably 15 years ago that explains how it works... 4x4 & Torque answers - JeepForum.com It's somewhere on this forum too but I can't find it since this forum's recent major layout change.
Thanks, also found this:
Limited-slip differential - Wikipedia
 

·
Knows a couple things...
Joined
·
48,981 Posts
Thanks Jerry, excellent as always. If TT does not have fishtailing, can the same be said about a Powertrax No-Slip?
Apples and oranges since the Truetrac is a torsion/gear actuated limited slip differential but the Powertrax No-Slip is an automatic locker. Automatic lockers tend to slide on icy surfaces.
 

·
Registered
Joined
·
607 Posts
K, I was wondering if the No-Slip's ratcheting might make it kinder and gentler. They have a more aggressive auto locker, the Lock-Right, which more aggressively eliminates wheel spin-up. In other words, they're saying the Lock-Right is more of a locker than the No-Slip.
 

·
Registered
Joined
·
11 Posts
That's not how LSDs work. A LSD can be either clutch or torsion/gear-based. Both work by coupling the spinning tire with less traction to the other tire with the most traction to increase the resistance seen by the engine which causes the engine to put out more torque. That gives more torque to the tire with the most traction which is often enough to get you going again. Engines but out zero to very little torque when it's not seeing any resistance/load to work into. Increase that resistance the engine sees and its torque output raises which is how the tire with the most traction receives more torque. How that happens can, again, be done with both clutch or gear based (aka torsion) LSDs.

Here's an article I wrote probably 15 years ago that explains how it works... 4x4 & Torque answers - JeepForum.com It's somewhere on this forum too but I can't find it since this forum's recent major layout change.
Thanks Jerry, just read that article, and sounds like you can answer a question I've always wanted an answer to. You may have answered it in the article, not sure! I have an '00 TJ, LSD in the rear D44, open in the front. If I have a rear wheel in loose gravel spinning and the LSD is trying to move me forward with the other wheel that has traction, what is the front axle doing? I think you said the front and rear axles are locked together by the Tcase? So assuming the front wheels have equal traction so one of them is not spinning being an open diff, those wheels will be pulling while the LSD is trying to push?
 

·
Knows a couple things...
Joined
·
48,981 Posts
The front axle is an open axle so if one of its tires is spinning, it's not going to be helping. The tcase does split the torque 50-50 between the front & rear but if a tire is spinning anywhere there's not going to be much forward momentum.

What you can do when a rear tire is spinning, with or without a LSD in that axle, is to pull the parking brake up a few clicks to give the spinning tire more resistance to work into which will cause the engine to generate more torque to give more power to the tires that still have traction. Or step on the brake pedal little to help both axles by giving any spinning tire more resistance to work into to cause the engine to generate more torque for the tires that still have traction.
 

·
Registered
Joined
·
14,211 Posts
I would not say the case splits torque 50:50

It locks the spin rate of front and rear driveshaft to equal rpm
If both wheels in front have good bite and both rears are up in air spinning pretty much all torque pretty much goes to wheels in front
If both rears have bite and both front are spinning pretty much all torque goes to rear

All the t case does in 4wd is make sure both driveshafts spin at same rpm so if one is a lot harder to spin it gets most of the torque to keep it at same rpm


Sent from my iPhone using Tapatalk
 
1 - 20 of 33 Posts
Top