Posi

[Northbound]

I'm getting ready to clean and paint the 71 chassis, and am planning a posi for, what looks like, the open Dana 60. I have kinda decided on a true trac but would consider others if anyone has experience with it, or other, as good or better, choice for a posi. Also, if you look at the tag, would that indicate it is a 4.10 gear set?

Thanks
NB

[Mbeef61]

I have a truetrac front and rear on my jeep wrangler and one in my 12 bolt truck. Love them. Easy/No special maintenance. Don’t even know they are there until you need it.

[Sheepdip]

Tag says 4.10 and 41 tooth ring vs 10 tooth pinion but unless you know for sure it has not been changed you can count them when you pull it.
The Eaton TruTrac is what I've used for years with never a problem, I currently am running 2 both in F**d 8"ers

[Accelo]

I believe 4:10's would have been the default differential ratio.

Below is the paperwork I pulled from a 3/4T I parted out years ago.
At the time I thought it was stock paperwork. I am not too sure anymore.

[Richard]

Tru-trac is a good diff. Just need to know the limitations. If you lift a wheel or one wheel has no traction it is basically an open diff.

[special-K]

No-Spin (Detroit Locker) was the factory HO52/72 axles.

I can't imagine someone changing out a different ratio ring & pinion and putting that ratio marker tab back on. Most never get put back on if cover was removed. GM didn't offer a taller ration in the Dana60, except with big block they used 3.54:1. Ford offered 3.73:1 from factory.

The Tru-Trac has always been my go-to front axle posi. I know they work well in the rear, too. Definitely a quality unit. Another great one for the rear is an Auburn Gear.

Another option that operates differently is the Gleason Torsen differential. Those put the power to the wheel "with traction". So, lift a wheel and power goes to the one on the ground

[Northbound]

tks all.

[cj847]

Originally Posted by Richard

Tru-trac is a good diff. Just need to know the limitations. If you lift a wheel or one wheel has no traction it is basically an open diff.

That is why I prefer a true locking differential to any of the "limited slip" versions.

[Northbound]

Maybe a couple more questions ... difference between 3 series gears and 5 series gears? I guess I'll have to pull the axle and count the splines also since they come in both 30 and 35 spline count ...?

[kwmech]

35 spline fits the front dana 60s and is assembled different 'cuz it spins the opposite way

[Mike C]

Originally Posted by special-K

I can't imagine someone changing out a different ratio ring & pinion and putting that ratio marker tab back on. Most never get put back on if cover was removed. GM didn't offer a taller ration in the Dana60, except with big block they used 3.54:1.

I was shocked to find the 3.73 ratio tag on the cover of my K30 and it’s 4.10 gears that had been swapped in.

Carrier break is 4.10 and down and 4.56 and up. If you run aftermarket 4.30 range gears, you would have to see what the manufacturer made them for.

I am a TruTrac fan in both ends of a vehicle. Other than price I couldn’t see not running one. Quick Performance probably the cheapest place for Yukon diffs and I haven’t priced them recently, but I got a 4.10 and down clutch type Dana 60 30 spline LSD from them for $289 two years ago. The Yukon Dana 60 diff is a PowerLock style and not a TrackLock. Either way LSD is mandatory in a vehicle IMO.

[special-K]

Originally Posted by Mike C

I was shocked to find the 3.73 ratio tag on the cover of my K30 and it’s 4.10 gears that had been swapped in.

Yeah, in later years GM offered 3.73s (front Dana60). Ford offered 3.73s, I believe in this era, in Dana 60s rears