4WD Off Road

[Ramroo]

Thought I would share a few things I have learned on my search.
Supposedly the Ram 1500s have had the BLD (Brake locking differential) since 2009 models.


- TC (Traction Control) and BLD are NOT the same thing.

- ESC (Electronic Stability Control) ON: Fights skidding and wheel spin with engine power reduction and wheel braking. Obviously NOT good for OFF ROAD (use Partial Off or Full off on ESC in 4WD).

- ESC Partial OFF: Engine power reduction disabled, Traction Control disabled, BLD (Brake Lock Differential) works.

- ESC Full Off: Engine power reduction disabled, Traction Control disabled, AEB (Automatic Emergency Braking) disabled, ACC (Adaptive Cruise Control) disabled, BLD works.

- For those 4WD trucks with open diff (no locker or LSD), the BLD will work well on the rear axle. Select ESC partial or full off.

- 4WD LOW: “Granny 4WD“ -Slow gearing, ESC toggle is disabled - goes directly to ESC full off, Lock rear diff if have it, Limited Slip rear diff always works, BLD works on front axle and rear if open diff.

-4WD HIGH: Use ESC toggle to go to Partial Off or Full Off, Lock rear diff, Limited Slip will work, BLD works on front axle and rear is open diff.

- 2WD: Can use ESC toggle to go Partial Off. Full off disabled (toggle will not let you). BLD works on rear.

With dual rear burnouts on trucks in 2WD with open diff and ESC in Partial Off is pretty impressive on how BLD kinda works like limited slip diff.

EDIT: Learned later that dual rear burnouts are possible with open diff with same rear tire resistance. Then BLD shines low speed in 4WD Low, varying rutted (getting a tire airborne or a tire with less traction than other), slick conditions such as snow and mud. Works on both front and rear axles.


A219EA7B267C&tocID=Jeep Brake Traction Control Explained | Stellantis Blog

 

[mcat79]

I’m my recent experience I was running in 4wd high with stability control off (quick press, I think a 10sec hold will do full disable?) and I would still get engine reduction when trying to spin the tires. You’re saying that partial off should still disable engine reduction?

 

[theblet]

- 4WD LOW: “Granny 4WD“ -Slow gearing, ESC toggle is disabled - goes directly to ESC full off, Lock rear diff if have it, Limited Slip rear diff always works, BLD works on front axle.

-4WD HIGH: Use ESC toggle to go to Partial Off or Full Off, Lock rear diff, Limited Slip will work, BLD works on front axle.

-

Nice write up. In 4 high and low, shouldn't BLD work on the rear if you don't have a locker or LSD?

 

[Ramroo]

Nice write up. In 4 high and low, shouldn't BLD work on the rear if you don't have a locker or LSD?

Yea,
But if you get a 4WD truck, it is either a locker, or limited slip differential In rear. And If I have a 4WD with locker, and I put it in 4H or 4L I personally think you should lock the rear diff. I suppose if you don’t lock it, the BLD will work also.

EDIT: Learned later you can get a conventional rear (open diff) axle on 4WD trucks.

 

[theblet]

Yea,
But if you get a 4WD truck, it is either a locker, or limited slip differential In rear. And If I have a 4WD with locker, and I put it in 4H or 4L I personally think you should lock the rear diff. I suppose if you don’t lock it, the BLD will work also.

My build sheet shows "Conventional Differential Rear Axle". I thought this meant open diff w/ BLD. I definitly don't have a locker because the button is missing.

 

[Ramroo]

I’m my recent experience I was running in 4wd high with stability control off (quick press, I think a 10sec hold will do full disable?) and I would still get engine reduction when trying to spin the tires. You’re saying that partial off should still disable engine reduction?

5 seconds or a little more to disable ESC to Full Off mode.

No power reduction in Partial Off mode of ESC.

There have been open diff trucks in 2WD in Partial Off and smoke both the tires on pavement for a long distance. EDIT: possible with open diff trucks, unlikely however.

 

[Ramroo]

My build sheet shows "Conventional Differential Rear Axle". I thought this meant open diff w/ BLD. I definitly don't have a locker because the button is missing.

Oh my bad. Didn’t think about that.

Should be against the law to sell a 4WD truck without a locker, or limited slip rear diff!

If your truck has an open rear diff (no locker or LSD), then the BLD will absolutely work on yours and other open diff trucks. And certainly the BLD works VERY WELL. Be sure and go Partial or Full Off on ESC.

 

[theblet]

Oh my bad. Didn’t think about that.

Should be against the law to sell a 4WD truck without a locker, or limited slip rear diff!

If your truck has an open rear diff (no locker or LSD), then the BLD will absolutely work on yours and other open diff trucks. And certainly the BLD works VERY WELL. Be sure and go Partial or Full Off on ESC.

I agree! Didn't really know it had open diff til after i bought it. BLD does seem to work well imo, at least the few times i used it.

 

[Dewey]

This is what started this discussion on the other thread. All I did was turn the traction control off with a quick button press. Didn’t hold in or delay in any way. Basically hit the gas and released the brake about the same time in 2 WD and DID NOT enable the Electronic Locking Differential on my dash or even limit anything in the gear selection.

Being a Back Country I wasn’t able to order the Anti-Spin Rear Differential like I normally could because the Electronic Locking Differential came included in the package. I assumed I would have an open differential so was quite surprised that both tires lit up evenly for so long I’m guessing it was about 150 feet. Motor was wide open going thru the gears. Obviously no power reduction as wheels were free spinning like crazy.

I find this BLD info interesting. Never knew about it and good to know I’m not driving around with a lame and worthless open differential. Hopefully it acts the same in the snow.

 

[mcat79]

5 seconds or a little more to disable ESC to Full Off mode.

I’m pretty sure what the attachment is saying is that you should not have any power reduction in Partial Off mode of ESC.

There have been open diff trucks in 2WD in Partial Off and smoke both the tires on pavement for a long distance.

However, there might be more of a difference from Partial Off, vs Full Off that what I listed. That was one of my biggest questions about the system actually. This is another reason I started the thread, maybe others know something different or more than I, but there is not much I can find written about how all is tied in and affected.

FWIW, I have the e-locker and while in 4high I was doing full acceleration turns on loose sand and that is when the engine would cut back. Maybe because of the tires rotating at different speed (vs straight line burnout)? I didn’t know about the full esc off, so I had partial off. I wish I could get back on the sand and retest in full off.

 

[Ramroo]

FWIW, I have the e-locker and while in 4high I was doing full acceleration turns on loose sand and that is when the engine would cut back. Maybe because of the tires rotating at different speed (vs straight line burnout)? I didn’t know about the full esc off, so I had partial off. I wish I could get back on the sand and retest in full off.

If your rear was locked, both tires had to be rotating at the same speed because they are locked. Doing turns with the rear locked, you have to be on a surface that the engine has enough power to break the rear end loose, like mud, gravel, loose dirt, snow, ice, wet pavement, etc. or the surface has to be so slick a tire can slide.
Maybe in the sand, the truck was fighting the turn, like turning on dry pavement with it locked.

 

[mcat79]

It was soft sand so it was breaking loose for sure. My other thought is the esc reenables at 39 mph, perhaps I was hitting that speed based on tire rotation?

 

[Ramroo]

It was soft sand so it was breaking loose for sure. My other thought is the esc reenables at 39 mph, perhaps I was hitting that speed based on tire rotation?

The only speed reference I know is where the truck will switch from Full Off to Partial Off at a Vehicle ( not wheel ) speed of 40 mph.

 

[Ramroo]

I agree! Didn't really know it had open diff til after i bought it. BLD does seem to work well imo, at least the few times i used it.

I know this is an old thread, but another thread about an aftermarket rear locker got me thinking about the BLD again.

Will you please just verify for me in grass or dirt, ESC partial off / TC off, 2WD, floor it and see if get 2 constant rears skids. I know you have an open diff, I just want to verify for myself that ALL differentials have it.

I have had a verification of rear locker rear (not locked) doing burnouts on pavement and my truck on grass, the LSD is always going to be limited slip, just no verification on “Conventional Diff Rear Axle”.

If you don’t want too, or if not convenient, no problem.

Thanks!

 

[theblet]

I know this is an old thread, but another thread about an aftermarket rear locker got me thinking about the BLD again.

Will you please just verify for me in grass or dirt, ESC partial off / TC off, 2WD, floor it and see if get 2 constant rears skids. I know you have an open diff, I just want to verify for myself that ALL differentials have it.

I have had a verification of rear locker rear (not locked) doing burnouts on pavement and my truck on grass, the LSD is always going to be limited slip, just no verification on “Conventional Diff Rear Axle”.

If you don’t want too, or if not convenient, no problem.

Thanks!

Sure thing. SO just press the TC button once?

 

[Ramroo]

Sure thing. SO just press the TC button once?

Yes, momentary push of ESC toggle is good ( partial disable ESC), this turns off TC (Traction Control). No need to fully disable ESC with paddle switch hold down, that just disables some other layers of the ESC that is no need too - AEB Automatic Emergency Braking, ACC Adaptive Cruise Control.

 

[Dewey]

Yes, momentary push of ESC toggle is good ( partial disable ESC), this turns off TC (Traction Control). No need to fully disable ESC with paddle switch hold down, that just disables some other layers of the ESC that is no need too - AEB Automatic Emergency Braking, ACC Adaptive Cruise Control.

Last time I pushed an held my TC button for a few seconds the entire dash lit up with all kinds of errors and then couldn’t turn TC back on. Thought I broke something. Only way to clear was to turn the truck of and start again. All was fine then. Wonder if it had something to do with my Tazer. Weird stuff sometimes happens with that connected.

 

[Ramroo]

Last time I pushed an held my TC button for a few seconds the entire dash lit up with all kinds of errors and then couldn’t turn TC back on. Thought I broke something. Only way to clear was to turn the truck of and start again. All was fine then. Wonder if it had something to do with my Tazer. Weird stuff sometimes happens with that connected.

Probably. Just curious, what do you do with the Tazer that is beneficial?

 

[theblet]

Yes, momentary push of ESC toggle is good ( partial disable ESC), this turns off TC (Traction Control). No need to fully disable ESC with paddle switch hold down, that just disables some other layers of the ESC that is no need too - AEB Automatic Emergency Braking, ACC Adaptive Cruise Control.

I don't have paddles. I think you can fully disable by holding down the TC button, but not sure. I know we don't need to do this for the test, but just for curiosity sake.

 

[Dewey]

Probably. Just curious, what do you do with the Tazer that is beneficial?

Kill3Honks. Worth every penny for that. Also changed my DRL to Amber and removed the fog light drop out with brights. The 0-60 timer is fun to mess with. Can also change the tire size which I eventually plan on doing in the future.

https://www.zautomotive.com/zpu/instructions/TazerDTUserGuide1817.pdf