Dana 44: Trac Lok vs Detroit TrueTrac ?

[yossarian19]

I've been driving the '57 a little while and decided it could use a positraction rear. A few reasons, which kind of define my goals, here:
1. If the driveway is wet, it's easy to spin the tires right through the gravel and keep spinning when I hit the clay underneath. Nothing says "Hot rod" like getting stuck in your own driveway.
2. Hit the gas hard enough, it does a one-leg burnout. I really want the truck to hook up hard. It's a 3900 lb truck with me in it, about 300 horsepower, 235/75/15 tires. Shouldn't be too demanding to make it hook up, right?

I've already got a Trac Lok carrier but I bought it used and noticed a chip out of a spider gear. New gears + clutches, assuming the ones I can find will actually fit, are $200.

Is the trac lok worth the trouble at $300 all in? Or is it worth the $200 more to get the eaton / detroit unit?

[yossarian19]

Hell with it.
Months ago, a guy put a 1/2 ton Dana 60 (D44 axle bearings & brakes with a Dana 60 center section) on craigslist for $600. Has a power-lok in it, too - the more aggressive OEM limited slip from Dana. Gent claims it should bolt in to a '57, guess I'll find out soon.
Today I offered him $400. I'll heave that in there and sell (or hoard) the Dana 44 stuff.

[roger55]

I put a new Trac-Loc in the Dana 44 I have in my '57 3200. Works great!

I bought it from Tom's Differentials.

[1project2many]

Trac Lok is very similar in design to the posi units found in many GM 10 and 12 bolt axles, with a spring applying "hold" pressure to clutches attached to either axle. Both wheels are "locked" unless one wheel presents enough resistance to turning that it can overcome the hold pressure applied by the clutch. As the clutches wear over time they lose their ability to lock or hold the wheels.

TrueTrac is a helical gear type differential that has the ability to vary hold pressure based on the difference in speed between the two wheels. Neither wheel is locked unless one wheel is turning at a significantly different speed. From an engineering perspective, TrueTrac makes fewer compromises. In more extreme situations such as off-roading the TrueTrac generally does a better job than the simple spring loaded clutch pack design of the Trac Lok. Practically speaking the Trac Lok will get the job done in most situations you're likely to be in.

Months ago, a guy put a 1/2 ton Dana 60 (D44 axle bearings & brakes with a Dana 60 center section) on craigslist for $600.

Is that out of a Jeep truck? In Mopar land an original D60 C-clip rear can be quite expensive.

[Lextech]

I put a Dana 60 with a Detroit Tru Trac in my 98 GMC twin turbo truck. It never chatters---It can't. It is as smooth as silk and always leaves two equal length black streaks.

Jeff

[_Ogre]

i'd put the diff you have in and not worry about the chipped tooth
ogre has a couple chipped teeth, i manage fine

[yossarian19]

Doing the math, the '44 I've got is going to need 1 wheel bearing + rebuild kit + brakes (backing plate, drums, etc - it's naked housing ends as-is) to be ready for spring perches. Adds up to as much as the Dana 60.
The 44 will find a home eventually. I might build it with disc brakes & throw it under my '75 Wagoneer some day, though it's equally likely I sell it first.

[joedoh]

Originally Posted by 1project2many

Trac Lok is very similar in design to the posi units found in many GM 10 and 12 bolt axles, with a spring applying "hold" pressure to clutches attached to either axle. Both wheels are "locked" unless one wheel presents enough resistance to turning that it can overcome the hold pressure applied by the clutch. As the clutches wear over time they lose their ability to lock or hold the wheels.

TrueTrac is a helical gear type differential that has the ability to vary hold pressure based on the difference in speed between the two wheels. Neither wheel is locked unless one wheel is turning at a significantly different speed. From an engineering perspective, TrueTrac makes fewer compromises. In more extreme situations such as off-roading the TrueTrac generally does a better job than the simple spring loaded clutch pack design of the Trac Lok. Practically speaking the Trac Lok will get the job done in most situations you're likely to be in.

exactly right and to add to that, a clutch type will usually work better on the street because technically it will never "lock", whereas the mechanical locking type will often lock suddenly and wont unlock until the axle speed falls below a limit. I had a no spin locker on a 3/4 ton and when it locked it was sometimes in the middle of a turn where the inside wheel became unloaded and spun and the lockup was sudden enough to make the truck drive straight towards the curb.