Torsen Differential Questions

[WtrskiAdic]

Looking for some input on upgrading the rear end of 2003 Fx4 Level II
So what happened and what I'm thinking of doing:
I'm rebuilding the rear diff because it started making all kind of noise and the ring, pinion, and bearings are all pitted very badly and lots of steel in the fluid so since I'm going replace all that I'd like to upgrade the stock the carrier to Torsen Differential or should I just replace it with the spring and clutch limited slip

 

[gw33gp]

That is a decision you need to make but I can tell you I very much like he Torsen that came with my FX4. I like it so much, I had one installed in the front differential also. The Torsen is set up with a higher torque bias than the typical clutch type LSD. The Torsen also does not wear like the typical clutch type which loses its limited slip capability over time.

A feature of the Torsen I like is; under acceleration, it almost works like a locker. I have not come across any undesirable characteristic of the Torsen in the 184K miles I have driven it, unless you considerer it undesirable having to be kind of easy on the accelerator pedal when taking off around a sharp corner. It likes to chirp the inside tire otherwise.

 

[WtrskiAdic]

Thanks that was the input i was looking for

 

[adsm08]

They are totally worth it. I grabbed one from a member for less than I could have replaced my clutches for, totally worth it. So smooth in the corners, if you aren't rough with it.

 

[tac1015]

Hey gw what do you think of the sound of the Gibson cat back? It is hard to make a v6 sound good, I make mufflers for a living and v6's allways sound kinda weird, is it loud, have an bad sound , what? What is a bama flash, a ecu reflasher and can it change how the pcm interprets the signal from the vss on a tire change?

 

[gw33gp]

The Gibson single cat back is not loud. It is just loud enough to hear the exhaust note without being annoying. Everybody has an opinion whether an exhaust sounds good or bad. I think the Gibson single sounds good.
The Bama flash is a reprogramming of the computer to improve performance and moves the speed limiter up. It can reprogram other things too. Mine cannot change the speedometer with different tire sizes or differential gear changes. More modern programmers can do this. I had to buy a separate unit that is used only for speedometer adjustment.

 

[hondaxr650]

I love my Gibson system. Loud enough to notice, without being obnoxious. Sounds great in my opinion. Nice deep tone.

 

[WtrskiAdic]

Anyone know if the ford racing torsion true-trac lok is suppose to have fiction modifier

 

[hondaxr650]

The Torsen diff. does not use friction modifier. Only clutch type units need it.

 

[Will]

I'm a little confused. In your first sentence you say you want to upgrade the axle of a 2003 FX4-II. That comes with a Torsen I believe. Or do you mean upgrade TO that axle, because you have a 2002 XLT in your sidebar.

The Torsen is a pretty good diff. If I found an FX4-II axle with it and it matched my front gears, I would swap that axle in. I would not buy a Torsen and install it--not a new one. Maybe not even a cheap used one.

Torsen and the clutch type axles are attempts to maximize traction and make it a smooth as possible so as to mask it from the driver. There is a compromise to both traction and smoothness. The clutch type is very simple and uses the natural side thrust of gears against each other to engage the axle without traction--and it does work pretty well. The Torsen uses inefficient planet gears to increase resistance to the act of differentiation, and they also increase their inefficiency through side loads, just like the clutches. They work pretty well. But they aren't as smooth on the road as a differential with efficient planet gears, and they aren't anywhere near as good when all hell is breaking loose as a real locker.

If I were going to replace a diff in a 4x4, I would replace it with a Detroit Locker. You don't need to mask the rear diff from the driver because you are the driver. If you know how the diff works, you can drive it smoothly. Any time, any conditions, you always have maximum power to either rear wheel. The axle is locked solidly--period. The only time a tire can unlock itself is if the ground pulls it along faster than the other tire. It only happens when you are going around a corner with traction--the outside tire has to take a longer path and speeds up, unlocking itself. It's very smooth and after the Detroit is worn it, you will forget about it. When you need it, both tires are digging 100%.

I've had a Detroit in my Chevy crewcab 2wd for 14 years and you would not be able to tell it was there, even if you were an 80 year-old granny. I've had a similar object in both ends of my 4x4 Ranger for as long. You will notice it if you floor it going around a corner and the inside tire spins, cathces up with the outside tire and then they both spin and the rear slips out from under you. That can happen on ice or on side-slopes on hills, so you need to be careful while you are getting used to it. But once you have conquored it--and it's not difficult to understand it once you drive it for 15 minutes--you won't regret it.

 

[85_Ranger4x4]

'03 FX4 LVII should already have a Torsen...

Before you do anything make sure you know what axle you have, if you have a 28 spline 8.8 a 31 spline FX4 Torsen won't work.

If someone stuck stickers and wheels on a plain FX4 you could get a nasty surprise if you just start ordering stuff willy nilly.

I don't do serious hardcore offfroading. For street and farm truck duty I love my clutch LS. It does everything a locker will do in mud/snow... spin two tires. Granted it doesn't last forever but it works great for me. Supposed to last about 100k, I have put 20k on the truck the first 15 years I have owned it so I am not that worried.