Detroit TruTrac Install?

Parts breakage only one side becomes disconnected when not in 4wd it's not like the old manual hubs where you disconnect both sides. So you'd have a half shaft that has a lot of "slippage" and one wheel connected to the ground with a lot of traction.

 

It's also much better than the clutch or cone style LS diffs. For what you are doing that'll be the best set up probably.

 

Price was certainly right during Black Friday/Monday sales too.

 

Didn’t even think about that. My ‘94 had manual hubs!

 

Yep with manual hubs your gears never spin with the set up we have the spider gears are always spinning you add some sort of tracion device and it'll want to turn the ring and pinion which would mean a bad day if not in 4wd.

 

I know the hummer H1, some are equipped with 2wd t-cases and have the front torsen differential. They don't have any problems there.

Doesn't the open diff up front while in 2wd still spin when driving down the road?

 

It's the way the diff dissconnects that's the problem the H1 doesn't have an axle disconnect the hubs are "constantly" locked so to speak that's why they have no issues. If you swap the FJ non disconnect axle tube I think you'd be ok but road driving manners would suck. It would act like you are in 4wd when trying to make sharp parking lot maneuvers hence an actuated locker would be better. Also in 4wd wheeling it isn't good to have the front wheels constantly "locked" together even with a LS like the torsion. The front diff isn't that strong to handle some of the forces while wheeling.

Yes our diff spins but is spun by the DS only the PS gets disconnected by an actuator so a torsion diff would be trying to counter act that since it would see no traction from the pass side and could really screw some stuff up by the "freewheeling" stub axle on the pass side.

 

I'm a little confused here.
In 2wd, the front drive shaft is essentially disconnected from the powertrain. So when going down the road, the front wheels are turning, which is turning the half shafts, which is in turn turn the differential?

 

Do you know how manual hubs work from back in the day?

 

Yes, I have a general idea of them. Aren't the tacoma's hubs always locked, thus always spinning the front?

 

Yes that is correct but there is an electronic actuator that disconnects the pass side stub shaft coming out of the diff before it gets to the CV axle. Thus only one side spins and one side freewheels which is why having a LS or any non swtichable locker is a bad idea in the front. It'll constantly be fighting itself and could break some stuff. The FJ did not have the actuated stub shaft and you could swap one of them in and do it but I would hate to drive that on the street, like I said the road manners would suck.

 

So the Ford Raptor has a Torsten diff in the front and IFS and CV axles like the Taco...

Add that a TW member @bwawuz02 has actually stuck a Torsten unit from the rear of a scion in his front diff and reports it works with no issues!

https://www.tacomaworld.com/threads/8”-ifs-clamshell-w-frs-torsen.561017/

So while no off the shelf LSD exists for the front of our Tacos I think you may have been slightly misinformed about what's possible

 

Ah I understand now. I guess its way cheaper to disconnect one axle shaft with an open diff, than to have a 2wd/4x4 transfer case.
Although why didn't toyota just use automatic locking hubs? That way both shafts get disconnected from the wheels?

 

The raptor doesn't disconnect the stub shaft. Also this guy put the FJ non ADD tube on the case which is what I have been saying. Just willy nilly putting one in the front and letting it roll with one side locked and the other unlocked is asking for trouble. Again that's what I've been saying. The stock torsion diffs from different vehicles are no where near set up as tight as the trutrac they have more slip so they would do much better in the front on the tacoma. You get something that is tight and it won't be very fun on the st. in tight parking lot maneuvers. Normal driving around town hwy fine it's the tighter maneuvers with them that will be your trade off.

 

Manufacturing costs. Essentially every 4wd truck with IFS is set up like this, this day and age (there are exceptions). They need to get freewheel to not have as much rotational mass to squeak out every last drop of fuel economy. Also auto hubs are expensive to create and no one wants manual hubs any more.

 

Well a torsen diff wouldn't 'lock up' unless the unlocked hub side saw a little friction. I guess it could happen and cause suprise 3wd.
But in most scenarios the torsen wouldn't be a bother since it would be like one wheel up front was constantly in the air. Unless the axle shaft itself provides enough friction to 'activate' a trutrac?

By chance do you know the bias ratio of the trutrac? They don't have it listed on their webiste. I know my old torsens were 4.5:1. I know some of Gleasons later diffs were as low as 1.7:1

 

Does the front driveshaft spin driving in 2wd?

 

I disagree just by understanding how these things work also you'll be wearing it out prematurely. There is some awesome material to read up on and some good videos. I have no clue what Eaton says the trutracs bias is they do say like 30% stronger than one of their other LS if they give the bias of that then you could calculate it. For the front you wouldn't want anything too aggressive.

It can but 99.9% of the time it does not due to the open diff. because the DS axle is just spinning the spider gears like crazy. The pass side is disconnected from the diff so only half the stub shaft is spinning and the cv axle. If you put the FJ ctub shaft and tube in then yes going in a straight like the drive shaft would spin in 2wd but as soon as varying wheel speeds occurred from going around a corner or something it would either slow way down or stop.

 

Okay. I've seen that people have put LSD in the front. I wonder what issues they are experiencing.

Then the real question is are there any aftermarket options to make the other side of the front axle disconnect? It would allow for a torsen up front and would be a tiny less drag on that wheel that still has a shaft connected to it

 

There is a guy that makes manual hubs for our trucks but it's expensive. Cheaper to go buy the FJ stuff and trick the 4X4 computer to thinking the ADD is still there.