lockers for a 71 9 inch

[71broncrollsport]

i have a 71 with 44 front 9inch rear with 411s,302, auto and 33s and 2 inch lift. i want to upgrage from a open diff in the rear to a locker or agressive posi. i will be doing mostly street driving and the occasional dessert bashing, i like the detroit but am not sure about its road manners. is the soft locker any improvemnet over the regular detroit? give me so addvice

 

[Bully Bob]

i have a 71 with 44 front 9inch rear with 411s,302, auto and 33s and 2 inch lift. i want to upgrage from a open diff in the rear to a locker or agressive posi. i will be doing mostly street driving and the occasional dessert bashing, i like the detroit but am not sure about its road manners. is the soft locker any improvemnet over the regular detroit? give me so addvice

If you decide on a true "locker" you should consider up-grading to 31 spline axles. some axle upgrades req. the large bearing axle housing.

A strong "posi" may be your better choice for mostly street. /

 

[BUCKIN67]

Hi there, To offer you some advise...Ford had 2 versions of clutch type lockers for the 9 inch. Equa-lock and trac-lock. The trac lock has better proformance and has stronger applications due to the design VS the equalock. Any cluth type is weaker than a Detroit style that has a ratchet lock. I agree with Bully Bob, go with the larger axle's unless you already got them if your considering changing carriers. The advantage of a Detroit is it is locked! The disadvantage is road noise when turning, sounds like turning a ratchet backwards, this is really not all that bad as FORD put them into reg passenger cars in the 60's-70's. If your in the snow,mud,ice....it IS posi for sure. I have a equa lock in mine and after a rebuild it preforms wonderful but will slip somewhat easily when under a load. Bottom line...if you want a no doubt proformance (off road rock climbing and such) go with the detroit, if ya want driveability and quietness with decent proformance (snow mud) a trac lock should be fine. 31 spline axle's will be a advantage and not much more money if your changing the carrier anyhow so I suggest going larger to! Hope this helps ya.

 

[S_bolt19]

Just my opinion, but if you are 75/25 road to dirt, I would go with a selectable locker like an ARB or OX locker. Yes, they are about half again the price of a Detroit or Auburn, but here is my reasoning and why I went with ARB.

#1 Road manners - A fully locked axle will push & pull on anything slick. An open diff doesn't to the extreme that a locked axle does.

#2 Tire wear - Locked axles go through tires about 1/3 as fast as an open diff does. Lets just say for arguments sake that you average 25k on a set of tires. With a fully locked axle, you are looking at about 17k miles on those same tires. So in 100k miles, on open diffs, you are looking at 4 sets of tires and with locked axles you are looking at between 5 & 6 sets of tires.

#3 Future costs - Looking back at #2 and combining the cost of each locker, here is what you are looking at while driving 100k miles. With a selectable locker, you are looking at 4 sets of tires (33x12.5x15 BFG MT TA/KM2 @ $192 a tire) & locker costs (ARB front & rear, pump & plumbing lines) = $4857.00. Those same tires, but substitute the Detroit locker & figure for the tire wear factor (about 6 sets of tires), you are looking at $5696.00 over a 100k mile range.

That is just my opinion. The upfront cost of any selectable locker is tough to swallow, believe me, I know. But you look at the tire wear factor, the wear & tear on other parts in the vehicle from a locked axle and the upside of a fully locked rig just isn't as pretty as one that lets you switch between open & locked. ARB & OX both are true full time lockers when they are engaged and a true open diff when they are not. Both have an advantage in off road applications because if you are in trouble and the ass end starts walking out on you with a fully locked axle, you have to know what you are doing. With the selectable, you have the benefit of an axle that is a lot more forgiving. On the road, you don't ever have to engage them, and they act just like your rig does right now with out anything in it.

But any way you go, get rid of the smaller splined axle and go with at minimum a 31 spline.