Open diff question

[jay c]

Hey fellows,

So my 2012 Ram Express has the 3.92 rear end but unfortunately has an open diff. I've been wanting to change to an lsd, but from what I understand it can be expensive. From what I know, with an open diff once you start to loose traction and spin a tire the computer cuts power and applies the brake to the spinning tire to get them both spinning again. Well I just got back from "testing" this and I left some nice 11s on the road. My question is was this a fluke or is the computer applying the brakes that good?

Team Destrucktive

 

[Redtruck-VA]

Don't know about the 12' but this is the way you might consider..
Lunchbox Lockers - What is a Lunchbox locker?

 

[toofart]

If both wheels are on a surface with the same traction (both on pavement, both on gravel, both on snow) they will pretty much both spin.

If one tire has lower available traction than the other, it will spin, and traction control will kick in. The problem is that TC can often limit throttle too. But it's still better than dealing with an open diff.

 

[toofart]

Don't know about the 12' but this is the way you might consider..
Lunchbox Lockers - What is a Lunchbox locker?

The '12s use a ZF 9.25 rear and I don't think there are any lunchbox lockers available.

I had a powertrax in my '03 Dakota, that was awesome.

 

[jay c]

If both wheels are on a surface with the same traction (both on pavement, both on gravel, both on snow) they will pretty much both spin.

If one tire has lower available traction than the other, it will spin, and traction control will kick in. The problem is that TC can often limit throttle too. But it's still better than dealing with an open diff.

I never go off-roading in my truck, so do you think better tires will help with my open diff dilemma?

Team Destrucktive

 

[TRCM]

If you are spinning both tires, then you either have a LSD, or the TC is working very well.

And yes, it will kill rpm if the tires spin too much

 

[jay c]

If you are spinning both tires, then you either have a LSD, or the TC is working very well.

That what I'm thinking, all the paperwork says I have an open diff so unless I'm really lucky and it slipped through with an lsd the TC is working overtime.

Team Destrucktive

 

[trikeffex]

My Open diff was leaving 2 black marks all the time..I actually thought the same as you that i might have gotten lucky..Well i guess it does depend on the roads because 75% of the time now its just a 1 wheel wonder.Now i did disable traction control and the abs system with my intune and it spun ungodly but yet again it was a 1 wheel wonder..It works similar to how the auto lsd is on the tundras..Its an open diff that uses brakes/ TC to limit power to the spinning wheel and sending power to the wheel with traction..It worked fairly well on pavement but not so much on anything offroad..
I too wanna swap to LSD and some 4.10's but for the price ill just have to be happy with what i have for now!!

Charles

 

[Chewy]

I tested my LSD this morning as we had about an inch of snow on the ground. I vowed after owning my 1990 2wd open diff truck to NEVER have an open diff again. My RAM Sport did great.

Keep in mind, a LSD will be a little more "fun" in the corners if you break the tires loose. Meaning, you'll go sideways and if you're not used to it, you can literally spin. NOW, with the nanny on the trucks, that's nearly impossible unless on a VERY slippery surface or going fast like on a highway.

What I'm saying is; a LSD CAN be a little trickier to drive in certain situations. I wouldn't buy a truck any other way though.

Chris

 

[jay c]

With an open diff, if I turn traction control off I'd only spin one wheel right? Because the computer won't apply the brakes to the slipping wheel?

Team Destrucktive

 

[TRCM]

With an open diff, if I turn traction control off I'd only spin one wheel right? Because the computer won't apply the brakes to the slipping wheel?

Team Destrucktive

Yes and no. You can't turn TC completely off unless you have a tuner, so if you turn it off, it will still come on, just at a higher threshold point.

 

[Razzaa]

Since TC causes u to lose power when u spin out what is the fasted way to launch off the line? 4auto?

 

[jay c]

Yes and no. You can't turn TC completely off unless you have a tuner, so if you turn it off, it will still come on, just at a higher threshold point.

Got it, the reason I ask is I turned off the TC button and still burned both wheels.

Team Destrucktive

 

[TomzExpress]

With an open diff, if I turn traction control off I'd only spin one wheel right? Because the computer won't apply the brakes to the slipping wheel?

Team Destrucktive

maybe yes/maybe no, in an open diff. on a flat equal traction surface both wheels will spin because traction is equal, the power is looking for path of least resistance, if traction becomes unequal the tire with the least traction will spin. TC applies the brakes to the spinning wheel in an effort to increase resistance to that wheel so the power will go to the wheel with the grip. TC usually won't work in a burnout situation because the brakes can't handle the power and the system becomes overloaded, hence the cutting of the power which is usually what gets you going. Hope this helps. Tom