[Dawn's Early Light Photo]

I see some are listed with this feature, some not -do all PM's have this? I also read that there is a brake-lock differential on PMs, not sure what the difference is, how they work and which PMs have what - can someone clear this up for me? Thanks.

 

[Chris]

No ProMaster has a traditional (mechanical) limited slip differential (a.k.a. "posi," "locker"). They all have stability control (ESP or ESC), which includes traction control (ATC) and "brake-lock differential." Brake-lock differential is similar to ATC because the system applies the brakes to a slipping wheel (in addition to reducing engine power, but to a lesser extent than basic ATC), which results in torque being transferred to the opposite wheel. By turning the ESP off, the brake-lock differential remains active, so you can spin both wheels at a similar speed if you are stuck in snow or mud. It's not recommended to turn off ESP above parking-lots speeds, because you will lose its other benefits (yaw control).

 

[Dawn's Early Light Photo]

No ProMaster has a traditional (mechanical) limited slip differential (a.k.a. "posi," "locker"). They all have stability control (ESP or ESC), which includes traction control (ATC) and "brake-lock differential." Brake-lock differential is similar to ATC because the system applies the brakes to a slipping wheel (in addition to reducing engine power, but to a lesser extent than basic ATC), which results in torque being transferred to the opposite wheel. By turning the ESP off, the brake-lock differential remains active, so you can spin both wheels at a similar speed if you are stuck in snow or mud. It's not recommended to turn off ESP above parking-lots speeds, because you will lose its other benefits (yaw control).

Thanks Chris. So all American market PM's have the same stability control features? I ask because I saw listings at the same dealer where some listed limited slip differential as a feature and others didn't.

 

[Chris]

Yes, to my knowledge, all ProMasters have the same electronic safety systems (ABS, ESP, brake-lock differential, etc.); perhaps they have subtle software tuning differences based on WB and whether 1500, 2500, 3500, but that is at the engineering level. These systems are not even optional; they are all standard.

I wouldn't trust any dealer's listing of any vehicle features. They often don't know and don't care about getting the details right; or they mix up one vehicle model with the next. (BTW, This is not a comment on RAM dealers; I mean ANY car/truck dealers.). I would only accept as credible information found in OEM-level sales and marketing literature (And even they occasionally contain errors), or in the best case, stuff printed on the window sticker of the vehicle you are considering (and make sure the sticker VIN and vehicle VIN agree).

As an aside, I'd like to see ProMasters offer (as options, at least) some of the "advanced driver-assistance systems" (e.g., blind-spot monitoring, lane-keeping assist, active cruise-control) that are showing up on Sprinter and others.

 

[rbisch]

By turning the ESP off, the brake-lock differential remains active, so you can spin both wheels at a similar speed if you are stuck in snow or mud. It's not recommended to turn off ESP above parking-lots speeds, because you will lose its other benefits (yaw control).[/QUOTE]


Have you actually observed both wheels spinning simultaneously when stuck in snow or mud?

 

[cRiPpLe_rOoStEr]

The brake-lock just emulates a differential locker, so it may lead to confusion.

 

[Chris]

I have not specifically observed this behavior of spinning both wheels on a ProMaster, but am familiar with these systems in the automotive industry in general. OEMs purchase these systems from suppliers (e.g. Bosch, Bendix, Teves) with specific tuning to optimize the performance on their vehicles, but they all work about the same.

 

[keithwwalker]

No ProMaster has a traditional (mechanical) limited slip differential (a.k.a. "posi," "locker").

I disagree, I don't think the PM has a LSD.
According to Allpar it is a brake-lock differential ie electronic control:

The electronic stability control includes ready alert braking (emergency stopping), brake assist, brake-lock differential system, hydraulic boost compensation, trailer-sway control, hill-start assist, drift compensation technology, rollover mitigation, and automatic brake lamp actuation.

http://www.allpar.com/trucks/ram/ProMaster.html

 

[cRiPpLe_rOoStEr]

AFAIK the only markets where a real LSD, outfitted by a 3rd-party, is offered for this platform are former French colonies in Africa and in the French Guyana. IIRC it's not compatible with the electronic stability controls used in the ProMaster.

 

[carryon]

I disagree, I don't think the PM has a LSD.
According to Allpar it is a brake-lock differential ie electronic control:

The electronic stability control includes ready alert braking (emergency stopping), brake assist, brake-lock differential system, hydraulic boost compensation, trailer-sway control, hill-start assist, drift compensation technology, rollover mitigation, and automatic brake lamp actuation.

http://www.allpar.com/trucks/ram/ProMaster.html

there is nothing to disagree with

that is what he said

he never said the PM has a LSD. It has brake lock diff system as you stated.

I think you may have read wrong

 

[keithwwalker]

No I didn't read it wrong, there is a true difference between a LSD and having electronics selectively apply brakes at each wheel. It is not a true LSD.

there is nothing to disagree with

that is what he said

he never said the PM has a LSD. It has brake lock diff system as you stated.

I think you may have read wrong

 

[30 Ounce]

 

[cRiPpLe_rOoStEr]

If the "brake-lock" traction control is related to the ESP, it might get disabled alongside the ESP when it's turned off. Anyway, since an all-mechanical LSD is pointed by suppliers as unsuitable to vehicles with ESP, don't expect it to become available in the ProMaster. BTW Eaton supplies Fiat with an electronically-controlled locker differential for some of its Brazilian compact cars and coupe-utilities, which automatically disengages at 12.5MPH, and maybe a similar system COULD meet the requirements of the segment in the ProMaster but I don't see it coming...