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Locker, True-Trac, Trac-Lok... whaddya runnin'?

DougG69

DougG69

Member
Well, I've re-done everything else in the driveline, only thing left is the rear end. Thought I should ask a few questions first.

What are you guys (and gals) running? Are you happy with your choice?

At what hp/torque level should I be looking at a nodular case?

I have a manual gearbox & "should be" around 425 flywheel hp +/- ... no dyno action so far.

I am leaning toward a True-Trac with solid spacer & Daytona pinion support. Although I think I can get a used/rebuilt Locker for about $200 less... but don't know if I'd like it for the street. Probably a good idea to go ahead & upgrade to 31 spline axles too.
 
I've run a Trac-Lok with my 4:11 gears. And that rear end was used and abused down at the drag strip (man does that sound wrong, so very, very wrong...) it always left two nice black marks and never had a problem.

I'm currently running a True-Trac with my 3:50 gears, also never had a problem. The true-trac has a solid spacer with it. When it arrived, it had the wrong yoke, the shop just zipped of the yoke and zipped on a new one in a couple of seconds.
 
I've had no problems with my true trac after 6 years on the road courses.
 
How are you going to be using it? TrueTracs are great for the street and road course, but I've heard they don't like a crapload of instantaneous power transfer, like when tires go from slipping to grabbing at 3krpm, so drag racing with sticky tires at that power level may justify a locker.

Otherwise, go TrueTrac:)
 
Thanks for the replies guys.

Looks like the True-Trac is pretty popular.

Advice I've seen on the 'net is that a street car with a manual transmission might not be so good with a Locker. This car is brutal enough to drive without adding fuel to the fire.
 
Tru-Track for me too.

No complaints on the road track or the street, but I haven't done any drag strip passes... well, no "sanctioned" drags.
 
I have a 3.70 Trac-Loc in my car. It works fine but if I were to do it again I would do a True Trac. I have a little over 550 rwhp. The Trac loc seems to be holding up well to that level of power.
 
"68EFIvert" said:
I have a 3.70 Trac-Loc in my car. It works fine but if I were to do it again I would do a True Trac. I have a little over 550 rwhp. The Trac loc seems to be holding up well to that level of power.
Click to expand...

Are you using a nodular case? Or a Daytona style pinion support?
 
None of the above items. I built the car originally for a N/A 302 with maybe 350 hp. That changed along the way. In fact I am still using the original 28 spline axles. The Lincoln Versailles axles are a littel thicker than the other 28 spline axles IIRC. I don't know if that would matter much or if they would be prone to breaking at the splines. Traction is my biggest issue and my tires break loose quite easily even with pretty wide sticky tires. Convertibles just aren't designed to put the power down.

I am about to start a new project, a 1968 Volve 1800S that will be sporting a 400 hp LS engine and a 9" rear end. I have contemplated changing the pumpkin and axles on the Mustang at that time and moving the existing pumpkin over to the Volvo at that time.
 
"68EFIvert" said:
None of the above items. I built the car originally for a N/A 302 with maybe 350 hp. That changed along the way. In fact I am still using the original 28 spline axles. The Lincoln Versailles axles are a littel thicker than the other 28 spline axles IIRC. I don't know if that would matter much or if they would be prone to breaking at the splines. Traction is my biggest issue and my tires break loose quite easily even with pretty wide sticky tires. Convertibles just aren't designed to put the power down.
Click to expand...

That is pretty much it, right there. Unless you are taking the car to the track and using slicks (or at least decent drag radials) it is pretty hard to break stuff. Set up the rear to prevent wheel hop and you'll be just fine with a stock Trac-Loc on most street cars. Drag racers have used 'em for decades as well.
 
I agree and hope that theory holds true for me. I am using a G-Bar rear suspension from TCP and have never had wheel hop. Even with 100+ foot burnouts. I am happy to have a lack of traction. It saves money on parts which are much cheaper than tires.
 
Well, it looks like the True Trac is out of the running.

I just grabbed some 31-spline axles from Summit in anticipation of this upgrade. These are marketed as a 'direct replacement' style, so they should work with the small bearing Mustang housing, and the standard small bearing.

http://www.summitracing.com/search/Bran ... yword=axle

I've been emailing back and forth with a builder & he said the True Trac requires an additional 9/16" length on the passenger side axle. So it looks like a Trac-Lok, or maybe a Detroit Locker after all.
 
Also, 68EFIvert - If you are still following this thread, the guy I've been talking to about the 3rd member says his neighbor has a 69 with the same setup I have, and doesn't use a nodular case or Daytona pinion support either. So most likely I will just go with a stock case.
 
"DougG69" said:
I've been emailing back and forth with a builder & he said the True Trac requires an additional 9/16" length on the passenger side axle. So it looks like a Trac-Lok, or maybe a Detroit Locker after all.
Click to expand...

WTF? Never heard that before. It wasn't that way on my old 9" nor on the one I had Currie make.
 
"silverblueBP" said:
WTF? Never heard that before. It wasn't that way on my old 9" nor on the one I had Currie make.
Click to expand...

Dunno. First I'd heard of it too. I assumed the guy knew his stuff though, he sells Ford rear end stuff on Evil-bay all the time. 100% positive feedback, this is apparently pretty much his thing.

I'll give him a call, as he included his phone # in the last email, and see what he says.
 
Ok, here's the scoop.

He said he was ordering some axles from Moser & they asked him if it was for a True Trac, and when he asked why it made a difference, they said for a full 1" or more engagement, you'd need the extra 9/16" on that passenger side axle.

So I guess it came from Moser... :shrug
 
"DougG69" said:
Also, 68EFIvert - If you are still following this thread, the guy I've been talking to about the 3rd member says his neighbor has a 69 with the same setup I have, and doesn't use a nodular case or Daytona pinion support either. So most likely I will just go with a stock case.
Click to expand...

Thanks for the info. Good to know I am not alone.
 
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