New member here. Recently bought an '06 Scab 4X4 XLT with 40k miles pretty well maintained. My last F150 was a V6 2wd that I installed a 03/04 Cobra LS diff with carbon clutches. That was the best mod! Could stand on it from a stop on a wet road and just launch! The '06 I have clearly is not LS . I bought a True trac for it having had great success using one in my '99 cobra setup for open track. I'll post some pics of the install when the install kit shows up. I'm looking forward to having some great traction soon!

 

Congrats. I love my trutrac on my 97 v6. Just one thing, make sure you only use convention diff oil not synthetic. It doesn't tell you that in the install instructions. If you use synth the rear will whine like a SOB. I called Eaton directly about the whine and they asked if I used synth. I cleaned out all the synth put in conventional 80w90 and the whine went away.

 

Well, this should be interesting. As it turns out, the truck is LS. In my initial "newbie" drive of the truck on a wet road it spun fairly easy so I assumed it was open. Subsequent driving made me realize it is an LS so I looked up the door code B6, 3.73 LS. The 5.4 just has more power than the V6 I had, Oops. I'm an idiot on occasion. I'm going ahead with the true trac install and will sell the LS.

I've read up quite a bit on the synth./conventional oil with the truetrac because of my experience with it in my '99 cobra. I've run a few different oils and the best one I found for it is Redline Heavy Shockproof synthetic oil. It clings heavily and will provide the cooling and bearing protection needed for OT use. Conventional oil doesn't hold up in the IRS diff since it's so small and has limited cooling. I've roasted a couple bearing sets easily. The Redline works great and makes no noise etc... I've decided to use that in the truck based on my research and experience.

 

I love the true-trac in my 04 2wd. Best mod I did hands down.
I've heard that the true-trac is a much better unit than the factory LS, but I have never heard from somebody that actually made the swap.
I'd be interested to hear what you have to say about the difference in performance when you are done.

 

Just be aware that Eaton recommends non-synthetic 80W-90.

 

Correct. Made the mistake of putting Royal Purple in mine.

 

I am using Lucas 85W-140 non-synthetic in mine with no problems at all, very quiet.

 

I ran the Lucas in my Cobra, it was the best of the conventional oils I tried. RP was not very good. Still going with the Redline heavy shock, that stuff is awesome. No overheating, smooth and quiet with the True Track in my Cobra. Thought I was going to have to rebuild the diff this winter after this season and won't have to, it's holding up great.

 

I made the switch two years ago in my 2008 Screw. There is really no comparison between the factory LS and the True Trac. The True Trac is the only way to go, IMHO, unless you are planning serious and frequent offroad treks, then you will probably will want a full locker. But for the weekend warrior who drives mostly on improved roads, the True Trac is quiet, always there, doesn't need friction modifiers, and it really works!

HYPO

 

Been driving the stock LS for awhile, what I've noticed is in a straight line, it works great. Go around a corner and the inside wheel which is also the wheel with the least traction is where the power goes and it spins while the outside wheel has no power and does not spin.

I installed the TrueTrac today, new timken carrier bearings, and arrived at .009 lash so within spec. With the rear up in the air, each wheel will spin freely and independent of the opposite side, atypical for a clutch style LS and this is the same as the cobra. I read the Torque Bias of the 9.75 is 3.5, which is higher than the 8.8 True trac bias at 2.5. Should work well in the truck. Soon as I have some drive time, I'll report back.

 

The TT is great, the inside wheel does not spin like the LS in turns and is very smooth all around. Works great in a straight line too, a bit better than the LS in the sense that when I went full throttle with the LS from a standstill, the right rear wheel would break loose and then spin while the left did not. The TT is very solid all around.

 

What happened when you used RP?
The Amsoil I used in mine worked OK but Eaton reports some oil causes a squeal or other objectionable noises... not to mention effecting the bias ratio. I ended up using Lubrication Engineer's (LE) LE607, which is no longer in production. It was a mineral 90 but with a very high tech additive package. Works well!

 

Glad to hear it's working out for you! What your saying helps me confirm that spending the extra $ for a True-Trac was the right choice for me instead of installing a trac-lok.