Best limited slip option for a Dana?

[MrC1]

I've got a C20 with the Dana 60 rear, but it's a one legger. I might step the gearing up form the factor 3.54s at some point and would like to stab in a posi unit at that time.

What's the best way to get one of these for the Dana? I don't mind if it's used as long as it's a rebuildable type. I have no interest in spending $800 on a shiny new one.

[MrC1]

Doesn't anyone know the answer to this? Surely some of you have upgraded to a Limited slip diff!

[MrC1]

No info????

[pumpkin]

If you need the traction of two wheels, the only way in my opinion is Detroit Locker. If you just want a bit more traction then I would go extreme duty Auburn. You can buy a locker used, but a posi I would buy new.

[MickMc]

Dana corp makes what I think is called a Trac Lock.
Very reasonable in cost, like everyone else its a carrier replacement.
Lots of places to buy. Not to name names but look for someone who carries Dana/Spicer parts.
I've used Trac Locks before, very forgiving, very drive-able.

Don't do a Locker in a street driven four speed. The back lash will drive you crazy. The tire chirping is cool for a while, the noisy differential is easy to over come with a good radio.
Air Locker is the coolest, but also the most expensive.

Mick

[MrC1]

Thanks! I don't want it to be clunking for sure, I just want to have 2 wheels driving. I may step up the gearing slightly, so that would be the time to do it.

[kwmech]

Factory limited slip in the D60s was a power-loc

[MickMc]

Powr-lok 2 piece case

Trac-Lok 1 piece case



Powr-Lok ( I assume you have 23 spline axles) Spicer #25499X

Powr-Lok ( I assume you have 16 spline axles) Spicer # 706208X


Trac-Lok ( I assume you have 16 spline axles) Spicer # 706034-2X

Trac-Lok ( I assume you have 30 spline axles) Spicer #706034X



I don't know what spline axles GM used, my guess is either 16 or 23.

If you change to 30 spline axles (I did) it makes life easy.

But in the sake of price
1. Find out the spline count
2 Trac-Lok is reasonable price

By the way, facing the differential cover, right side, middle of tube is a date code and a bill of material, always nice to have and good reference for selecting the correct parts, Spicer bases EVERYTHING on this number.

Mick

[BCOWANWHEELS]

Track lock is not a posi BUT A LIMITEEEED SLIP ALSO YOU,LL NEVER HAVE 2 WHEELS PULLING, power lock is a posi. Power lock is for sure both wheels pull but you will have a noticeable increase in tire wear and fuel milage will drop some.

[MickMc]

Originally Posted by BCOWANWHEELS

Track lock is not a posi BUT A LIMITEEEED SLIP ALSO YOU,LL NEVER HAVE 2 WHEELS PULLING, power lock is a posi. Power lock is for sure both wheels pull but you will have a noticeable increase in tire wear and fuel milage will drop some.

So I'm trying to help the guy out...

SO whats the difference between a 'posi' and a 'limited slip'?

AND what is the difference between a Powr-Lok and a Trac-Lok?

And how is 'for sure both wheels pull' with a Powr-Lok?



Mick

[MrC1]

It's my understanding that "posi" or limited slip (interchangeable terms) means the unit locks the wheels together if under torque and one spins faster than the other. Otherwise only one wheel is driven.

A spool permanently locks the axles, making turns difficult and really wearing on your axles. This is great for race cars tho.

MickMc, thanks for the info! I thought that Dana 60s all had 35 spline axles. Shows what I know. I find it hard to believe they made axles as small as you're saying, however. 16 spliners must be the size they use in Toyotas! That's really small! You sure about that or am I missing something here?

[MickMc]

Originally Posted by MrC1

It's my understanding that "posi" or limited slip (interchangeable terms) means the unit locks the wheels together if under torque and one spins faster than the other. Otherwise only one wheel is driven.

A spool permanently locks the axles, making turns difficult and really wearing on your axles. This is great for race cars tho.

MickMc, thanks for the info! I thought that Dana 60s all had 35 spline axles. Shows what I know. I find it hard to believe they made axles as small as you're saying, however. 16 spliners must be the size they use in Toyotas! That's really small! You sure about that or am I missing something here?

MRC1
Sorry, I was asking for bcowanwheels to speak up...

Most differentials use some sort of side clutch plates causing both axles to drive. If one axle can overcome the pressure of the clutch plates that axle will stop being driven and all of the power will be driven to the other axle. Simple system but everyone has their own take on a simple idea

A locker is two halfs, left and right (like big teeth or gears) engaging and dis-engaging, hince the locked together or not locked together, and the noise and backlash to go with it.

A spool is one solid piece of steel (the carrier) the axles do not hve a side gear and are "as one" with the ring gear, very effective but hard on parts. If you have ever tried to push a race car with a spool you soon realize how much give a differential provides.

As for axles, alot of the older trucks have corse spline axles, mostly I've seen 16 spline.
My 60 out of a 70's Ford had 16 spline axles that I changed to 30 splines.
30 splines are the most common, but there are alot of 16's out there.
23 spline I have seen but maybe not as much because Ford used 60's in every 3/4 truck and Cheverolet only used 60's for few years.
30 spline and 16 spline have the same axle diameter, but as you increase the number of splines the strength increases (surface area increases)
35 spline axles are exclusive to front Dana 60's.
You can't fit 35 splnes in a 60 rear without some machining.
35 spline axles are larger in diameter than the 30's.


Mick

[special-K]

I have the factory Power-lok/3.54 and it`s perfect.Most guys would kill for your 3.54s these days...plenty of pulling power and the tallest possible gears in a 3/4t.I`d just look for a 3.54 Power-Lok and bolt in.If you do your own diff work look for a power-Lok and install.The next step up in money would be a new Auburn.

[1969 GMC]

posi and limited slip are THE SAME THING. posi was just gm's nomenclature for one.

the track-lock and power lock are both limited slips or posis, but the power lock is stronger. like special-K said, it was OEM in the d60 rears in our trucks, and what i would look for if i were you.

also, the d60's under our trucks have 30 spline axles. at least my '69 did.

[BCOWANWHEELS]

Sorry fellas but the power lock has clutch disc's. And the track lock doesnt. The power lock will only give when your on hard pavement and turn tight, both wheels will always pull. A trac lock one or the other wheel will pull. I,ve been installing these in 4x4 trucks for 15+ yrs. The power lock has a 2 piece carrier and the trac lock has a 1 piece carrier and is torque sencing. Power lock is twice the diff as trac lock and thats why A TRAC LOCK is half price. I'd only install a power lock if you for sure want a true posi but expect to install new rear tires every 20,000 miles as it will eat em if the power lock has good clutch plates. Also when you go around a corner especially on wet roads the rear end will break loose real easy especially on snow, mud etc. Only you can determin how you want your rear setup. Heres a list of the different differentials in order of harshment.
1. Open carrier
2. Trac lock
3. Power lock
4. Detroit locker
5. Spool

[70rs/ss]

Older thread, but I just popped the cover off my Dana the other day and I have the 3.54's and what I believe to be the Power Lock as there are a ring of blots on the end of the carrier and the carrier looks to be 2 pieces? So anyone w/picts??

[deadmoon]

i have 72 c 20 with a dana 60 and last fall I installed a detroit locker.one of the best things done with my truck.

[Dr. Evil]

So what does the SPID G87 Max Traction Axle mean? is it a posi?

[kwmech]

Originally Posted by 70rs/ss

Older thread, but I just popped the cover off my Dana the other day and I have the 3.54's and what I believe to be the Power Lock as there are a ring of blots on the end of the carrier and the carrier looks to be 2 pieces? So anyone w/picts??

Yes 2 piece carrier will be a power-loc, and they are rebuildable.

[70rs/ss]

Originally Posted by kwmech

Yes 2 piece carrier will be a power-loc, and they are rebuildable.

Is that better than the trac-loc? How strong is it, say vs a 14 bff rear? I have both and want to build a 1 or 3/4 ton 4X out of my Burb??