Looking For Opinions Aftermarket Diffs

mchan68 · July 19, 2012

I have a customer whom just traded in his 2008 F-250 6.4L for a manager's demo 2012 F-150 3.5L Ecoboost 4x4 truck and wants me to install an Auburn locking diff. This truck is a crew cab loaded with all the bells and whistles type truck but no locking diff. It is a 9.75" open rear end with a 3.31 ratio. Just curious if you guys have any input on this. I know from personal experience if a vehicle is loaded up, but not equipped with a locking diff, there must be a good reason for it (ie traction control). Have any of you guys performed such a swap? What were your experiences with it?

Buddy_M · July 19, 2012

I've installed only one Auburn unit and that was several years ago in a mud toy for a guy, and he loved it. I have also installed a few of the Detroit True Trac units, and will be installing another one next week in a GM 10 bolt rear end after the new carrier and bearing kit arrive next week. After seeing how they are built I lean towards recommending the True Trac units, only because of the lack of any kind of clutch plates/cones so there is no worry about what kind of oil can be used or have to use an additive. I have also installed an Eaton posi(clutch plate type) in the rear of my 99 F250 which came stock open. Only noticed a difference on ice, snow, and mud and had much better traction to get through.

I also have a LockRight in the front axle, and haven't gotten stuck yet having that combo.. however having a locker in the front definately will make for some interesting driving situations if you hit dry pavement or gravel and try to turn.

Brad Clayton · July 19, 2012

I upgraded my all wheel drive 5.0l Explorer to a limited slip rear dif and it can get kinda hairy in a snow storm, she likes to do donuts.

Matt Saunoras · July 22, 2012

I'm running a tru-trac in the rear of my F-250. Not as fail safe as a locker but it gets both wheels spinning. I will say it is no substitute for 4-wheel drive. In snow it just spins both rear wheels instead of one.

From what I've read a lot of guys with trucks run a locker in the front. A locker in the rear might just do what my truck does

I believe the auto locking diff that comes factory equipped will automatically disengage at a certain speed, lets say 20mph, so it doesn't have a negative effect on traction control (whatever kind it may have).