Limted Slip Differentials with Traction Control vs. E Lockers

[dhalsey]

I have an 2002 4wd 4runner with no e locker. I have been researching doing an e locker retrofit on my 3rd gen. The problem is that I have 3.90 gears and I will have to re gear the front dif as well. Cost comes into play.

I have researched Detroit truetracs as well and haven't been able to find the answer to my question.

What would a limited slip like a truetrac be like with the factory traction control enabled as well?

I had a 2wd truck with an e locker and it was shocking what that truck could do.

The trac system on is a limitation, but I imagine that a mechanical limited slip plus a electric limited slip would work together to keep a lifted tire from spinning.

Is there any flaw to that logic?

Thanks for the input in advance

 

[white_n_slow]

It is my understanding that a mechanical limited slip will become useless if a tire is lifted off the ground. They're great for limited traction situations like snow and mud when both tires have *some* traction, but aren't going to do you much good in a lifted tire scenario.

I don't know enough about how the traction control system works to guess how TC might get along with a LSD.

If cost is a factor, you should consider a lunchbox locker like the Aussie. They're about $300 and kick butt off road.

 

[dhalsey]

My understanding of the traction system is that it monitors spinning wheels and applies braking forces to the spinning wheel. It is basically a electronic limited slip.

I have read that owners with mechanical limited slip diffs found a way to trick their lsds if they ever lifted a tire. Evidently applying a little bit of ebrake will stop the lifted wheel and transfer power to the wheel on the ground.

I guess my question is will the trac system work the same way? If it did a electronic traction control combined with a Detroit truetrac might be a powerful combination.

It makes sense in theory but I'm not sure how the real world application would behave.

I'm sure that someone has an 01-02 that has tried a mechanical limited slip. I just have to find them.

Anyone?

 

[JayRolla]

Like stated as soon as the tires comes off the ground your limited slip is useless. And like you said e locker, regear, wiring can all get expensive. Like the detroit ratcheting locker look into the Aussie Locker. Its under $300 and one in the rear works great. You dont want it in the front. But they will lock your rear end and unlock when turning. Snow is a little bit more difficult when in 2wd since your always locked but in 4wd its fine. Thats my next mod for my truck and then I will get an air locker for the front.

 

[dhalsey]

I'm a little worried about an auto locker as this is my daily driver. I guess I could just try the true trac. That is an inexpensive experiment. I'm not sure why traction control wouldn't kick in though.

 

[98OzarksRunner]

I have an 02 with a Detroit TruTrac. It is true that a lifted wheel will spin since it takes a little friction for the LSD to lock up. You can apply a little brake and it will lock and move the truck (the TruTrac manual says to do that as well). My truck goes very well - I usually run loose, muddy, rocky logging and forest roads in 2WD (and my buddy a while back was in 4WD to keep up). It also has very good road manners - I don't even know it's there, unless I need it on slippery roads.

I don't know if traction control would help. My experience is that the traction control just reduces power from the engine (probably pulls timing) rather than applying brakes (though it might, I just haven't seen that). I have the Andy Mod 2.0 (turn off VSD and trac control) so I turn it off when off-road. I also turn it off in the snow since it is scary to be trying to cross a road with traffic and have the trac control say 'we're not going anywhere - I don't car if cars are coming at us!'.

 

[dhalsey]

I have an 02 with a Detroit TruTrac. It is true that a lifted wheel will spin since it takes a little friction for the LSD to lock up. You can apply a little brake and it will lock and move the truck (the TruTrac manual says to do that as well). My truck goes very well - I usually run loose, muddy, rocky logging and forest roads in 2WD (and my buddy a while back was in 4WD to keep up). It also has very good road manners - I don't even know it's there, unless I need it on slippery roads.

I don't know if traction control would help. My experience is that the traction control just reduces power from the engine (probably pulls timing) rather than applying brakes (though it might, I just haven't seen that). I have the Andy Mod 2.0 (turn off VSD and trac control) so I turn it off when off-road. I also turn it off in the snow since it is scary to be trying to cross a road with traffic and have the trac control say 'we're not going anywhere - I don't car if cars are coming at us!'.

Great feedback thank you. I have the andy mod done as well. Just to clarify, you havent had the traction control on when you have ever lifted a tire? Could you do an experiment for me? I don't suppose you have terrain nearby. somewhere that you test out the traction control?

 

[white_n_slow]

I'm a little worried about an auto locker as this is my daily driver. I guess I could just try the true trac. That is an inexpensive experiment. I'm not sure why traction control wouldn't kick in though.

It sounds like you're not too interested in going this direction, but an Aussie locker is perfectly daily driver friendly, in my experience. Especially if you do not do a lot of on-pavement snow driving. Once you get used to it, you don't notice it at all (when the windows are rolled up, lol).

 

[Kurtis]

Great feedback thank you. I have the andy mod done as well. Just to clarify, you havent had the traction control on when you have ever lifted a tire? Could you do an experiment for me? I don't suppose you have terrain nearby. somewhere that you test out the traction control?

There are normally 2 types of Traction Control in a vehicle. The type that allies the brake to that specific tire that is spinning so it causes the differential to apply more power to the opposite tire. Then there is what we have. We have an electronically controlled Traction Control System. Meaning if you loose traction when you apply the accelerator the truck will automatically slow the engine. It does not kill the engine. It just stops it from accelerating.

If you wheel your 4Runner on a regular basis, then a Detroit Locker might be for you. An "Lunch Box" locker could also be a good substitute if you don't wheel hardcore.

If you go on dirt roads or snow and want that little extra traction, an LSD would be good. You can apply the brakes and it will help transfer power to the tire that is on the ground. This also works with out an LSD but it is more effective with one.

 

[98OzarksRunner]

Great feedback thank you. I have the andy mod done as well. Just to clarify, you havent had the traction control on when you have ever lifted a tire? Could you do an experiment for me? I don't suppose you have terrain nearby. somewhere that you test out the traction control?

I jacked up one wheel and tested it. With the traction control on and no brake, traction control pulled almost all power from the engine but did move the truck forward at a crawl. The traction control apparently did apply a little brake to the raised wheel, but there was so little power it didn't move it much (which is fine since I used a floor jack to raise the wheel!). When I applied the brake a little (used parking brake) the diff transfered power to the other wheel better and the truck moved out, but traction control was still pulling engine power.

So, in answer to your question, the TruTrac doesn't seem to work well with one wheel lifted with traction control and no braking, but does work with braking and traction control on, but moves very slowly, and probably wouldn't pull the truck up a hill (no power). But it works much better with traction control off using the brake to transfer power to the other wheel.

 

[dhalsey]

I jacked up one wheel and tested it. With the traction control on and no brake, traction control pulled almost all power from the engine but did move the truck forward at a crawl. When I applied the brake a little (used parking brake) the diff transfered power to the other wheel and the truck moved out, but traction control was still pulling engine power.

So, in answer to your question, the TruTrac doesn't seem to work well with one wheel lifted with traction control and no braking, but does work with braking and traction control on, but moves very slowly, and probably wouldn't pull the truck up a hill (no power). But it works much better with traction control off using the brake to transfer power to the other wheel.

Thank You!!
It looks like a locker of some sort is what I'm looking for. The aussie zip locker looks like my best option.
Thank You for your time.

 

[98OzarksRunner]

Thank You!!
It looks like a locker of some sort is what I'm looking for. The aussie zip locker looks like my best option.
Thank You for your time.

The real reason it doesn't work well with traction control is due to the design of the traction control system, not the diff.

The TruTrac works well for me, but it is pricey. It's about $450-500 in the US, while an Aussie locker is about half that. The owner of my previous 4Runner (98) had installed one to replace a bad factory diff. Since it only had 10K miles on it I transferred it to my newer 4Runner. If I didn't 'inherit' it I probably would have gone with something else. It does have great road manners - good off-road traction and 'transparent' on-road is a nice package. But I don't do hardcore rock crawling - overlanding/expedition stuff is my speed (too old to get thrills from breaking things anymore - I just want to know what's at the end of that dirt road or trail).

 

[dhalsey]

The real reason it doesn't work well with traction control is due to the design of the traction control system, not the diff.

The TruTrac works well for me, but it is pricey. It's about $450-500 in the US, while an Aussie locker is about half that. The owner of my previous 4Runner (98) had installed one to replace a bad factory diff. Since it only had 10K miles on it I transferred it to my newer 4Runner. If I didn't 'inherit' it I probably would have gone with something else. It does have great road manners - good off-road traction and 'transparent' on-road is a nice package. But I don't do hardcore rock crawling - overlanding/expedition stuff is my speed (too old to get thrills from breaking things anymore - I just want to know what's at the end of that dirt road or trail).

I don't do any rock crawling either. I just need something to get me out of trouble. Its still a hard decision. If I do start rock crawling though I think I would regret going lsd . thanks for the experiment. It would be nice if these trucks had the kind of traction control that actually stopped the tire that was spinning instead of cutting power Hopefully this thread can help someone else as well.

 

[thebrandon]

I used to have a Nissan Frontier. It had a very impressive LSD. It was worlds better than an open diff. A good quality LSD can still move you even if you lift a tire, much like mine did. Now, compare the best LSD to a locker and you still have no competition. I love my E-locker and would never consider an LSD for the rear end. If you want to get out of trouble, get a locker.

 

[the great him]

why do you think you have 3.90 gears!? are you a 2wd or 4wd? cause only 2wd 4runners had 3.90s so unless someone swapped the rear diff with a 3.90 but then your front diff would be different anyways. have you thought of going with say an ARB?

 

[dhalsey]

why do you think you have 3.90 gears!? are you a 2wd or 4wd? cause only 2wd 4runners had 3.90s so unless someone swapped the rear diff with a 3.90 but then your front diff would be different anyways. have you thought of going with say an ARB?

I have a 2002 sr5 4wd. It came from the factory with the 15 inch rims and the small base model tires. When I went to the 265/70/17 I'm running now my speedometer was of by 6 mph. If I'm going 59 it shows on the GPS 65.

As far as how I like them I think they work well. I'm running p rated tires right now and they weight about 41 pounds a tire. If I went up a size or had any heavier of a tire on it I think it would suffer. Right now though it suits what I use it for well. I'm getting 17 with mixed driving and 21-23 with all highway miles.

The options are the arb or the Yukon zip. The Yukon zip is getting the nod for price.

Im wondering if I should regear but I have convinced my self that going to a 285 will add at least 7 pounds per tire even with the lightest rubber. Its not so much the size of the tires that kill these things but the weight.

 

[the great him]

again you DO NOT have 3.90 gears, i still dont know why you think you have them, as no 4wd 4runners ever came with 3.90 gears, only 2wd runners had those gears. if you do an ARB or trutrac you wont have to regear at all...

 

[dhalsey]

again you DO NOT have 3.90 gears, i still dont know why you think you have them, as no 4wd 4runners ever came with 3.90 gears, only 2wd runners had those gears. if you do an ARB or trutrac you wont have to regear at all...

Why is my speedometer off by so much after I went to a 265?

 

[BrianSD_42]

Why is my speedometer off by so much after I went to a 265?

Stepping back from the WHY question ..

How did you come up with the 3.9 number? Was that a cAlculation you made?

 

[the great him]

Why is my speedometer off by so much after I went to a 265?

idk, but i know for a fact that you do not have 3.90 gears, and i have never seen your runner or met you... toyota never made a 3.90 geared 7.5 clamshell front diff, and you can not get 3.90 gears for one. the lowest (numerically)-tallest geared you can go in the front diff is 4.10.... and some runners and tacomas came with 4.10 elockers, but most were 4.30, but not all.