Front diff question/ compatibility

[Pierre T4R]

Hey guys,

I have owned my first 4x4 for two years now and I'm pretty new in the off road world and I haven't done much to my truck except bigger tires 285-70 r 17 and a basic lift. I found that I had lost too much driveability so I had the gears changed to 4.56 and got an torsen diff installed in the rear. I am very pleased with the results btw but to my surprise I could not find a torsen for the front and I was wondering if maybe a diff from another Toyota model or other brand would be interchangeable and give me more options to find an lsd or torsen or something of the kind to put into the front. I am not a big fan of lockers because of the price and I don't think I need one to be honest.

I am a light duty off roader and do lots of driving on the road as this is my only vehicle. Love to drive it in the snow and having an extra wheel working up front would be better then just having one spinning uselessly and not getting me anywhere.

My 4Runner is a 2008 Limited awd model.

Best regards to everyone and thank you for the help.

 

[Bumbo]

Just to confirm you did change both front and rear gear-sets to 4.56?

I’m surprised you opted for a mechanical limited slip in the rear as it does little to help off-road when a tire is in the air and there is a loss of traction, but does make a difference in snow or when accelerating though turns.

Truthfully with how you are using the truck, I would have saved the cash and just run open differential in the front. ATRAC alone should provide enough assistance for those times you do have wheel slip in snow.

That said, It's been a while since I did any research, but I thought they did exist.

 

[Pierre T4R]

Yes I have gotten the gears replaced front and rear. The front diff is open for now. I haven't had the chance to test the torsen off roading since the install unfortunately and I am aware of the flaws they have. I figured that for less then half the price of a locker it would be better then keeping an open diff.

I just don't understand why they don't seem to make them for the front on our trucks.

 

[Bumbo]

I certainly would not call the performance characteristics of the torsen LSD flawed. They are well designed for the application they are best suited for.

Your center transfer case is a torsen mechanical limited slip with the option to lock it. It’s what allows you to drive on road without binding and scrubbing tires, locking it provide 1:1 power to the front/rear for off-road use.

You might want to call around to some gear shops to see what your options are but I would just leave it open. ATRAC works good enough for snow and light off-road driving.

To a degree I am curious as to how the truck now drives with a torsen in the rear. I would be very interested to put this thought its paces in the desert.

 

[Pierre T4R]

I really like the torsen center diff, you can feel it transfer power from the rear to the front when climbing steep snowy hills for exemple.

For the feeling on how it drives with the rear torsen it just feels like there's nothing to it which is nice.

I have spoken with the two top shops in my area and sadly Toyota's are not that big here and good knowledge is scarce.

We don't have deserts here but the closest thing we have are sand pits.

 

[Bumbo]

Well, you got me curious so I called the two gear shops I typically work with. Neither of them knew of any Torsen or Truetrac (worm gear/ring gear) options for the front diff.

Selectable e-Locker or air lockers yes, but not mechanical LSD. They also advised against anything clutch based LSD in the front as it may negatively affect steering during operation.

 

[Pierre T4R]

Clutch type diff tends to wear out quickly from what I’ve been told about 30,000km life span for the clutch pack due to off road abuse. That can get costly when you use your vehicle on a daily basis on top of excursion trips. That gave me another reason to go the mechanical root. Too bad no manufacturers make a Torsen, I would have been first on the list to get one.

Whenever I start getting stuck too often and towed by friends, I’ll consider a locker for the front then.

 

[Pierre T4R]

Thanks for looking into it on your side.