Question For Carlton Bale

[lynnbrown]

Carlton, I was told by my dealer when I ordered my new HO 48re that the torque converter will not be under warranty if used with the Jacobs e-brake. Do you have a info on this.

Wyolaramie.

 

[DBVZ]

I was told the same, and asked the same question on several forums. As I understand it, the 48re is "e-brake compatable", and some testing is supposed to be in-progress. When Dodge is confident the 48re will stand up to the reverse brake pressure they MAY approve it for use with an e-brake; which should mean the warranty will be OK. So far I have only heard second (or 22nd) hand about testing with the Jacobs brake, and nothing about PAC or any other e-brake alternatives.



Mine is supposed to be in transit, second rail arrival. The next status change should be at the local rail yard, and delivery in just a few days - unless they lost or damaged it. Perhaps by February 1. Then the real fun begins!

 

[jelag]

I was at the PacBrake factory last week..... we talked about the exhaust brake for the automatic..... they are going to recommend the same part number C14030 once DC give the transmission their blessing and approves it... .



On another note..... it looks like their won't be an exhaust brake for the new powerstroke..... when testing the engine it was found the valves floated at 22 psi of back pressure..... not enough to do any good as far as PacBrake is concerned... When Navstar was asked they said they had a limited budget from Ford to develop the engine and it wasn't in the budget for next year...



The old first generation engines had valve springs that would allow 35 psi and you could upgrade the exaust valve springs and increase the back pressure to 60... .....



Have a great evening... .



Jim

 

[DBVZ]

Jim and Carlton,



Does the Jacob's Brake and/or the PAC Brake "Know" how to tell the 48re transmission to stay locked during operation? How is that accomplished?

 

[Carlton Bale]

48RE Update

Due to some delays, testing of a 48RE transmission with the Cummins/Jacobs exhaust brake will not be completed before the end of March at the earliest. That's the best estimate of an announcement date I can give at this point.



As I understand it, the 48RE transmission was designed to be e-brake capable. However, endurance testing has to be completed before warranty certification is given.



If you add a brake now to your 48RE, you would be taking a chance that the e-brake is not approved for that transmission. If a brake causes a transmission failure, it would not be covered by warranty in this situation.



The 48RE transmission has higher internal pressures that allow it to transfer reverse torque. So, this reverse torque will occur even without a brake. However, because diesel engines do not have any throttle/butterfly or any other restriction, there is almost no deceleration caused by the engine and almost zero reverse loading on the transmission when coasting.

 

[jelag]

Carlton please correct me if Im wrong.....



There were some vendors that offered a lock up condition on the early transmission used in the second generation trucks... . it held the fluid pressure up to keep the torque converter and clutch packs locked up to transfer the power to the engine so that the exhause brake would help absorbe the energy.....



I'm assuming that the new transmission will have these features built into them. The ECM looks for the switch on the exhaust brake to be ON and when it see's the ON condition, will activate the exhaust brake at the required time..... This is when the engine is at idle and now per Carlton when the cruise control tell's it come on when the truck exceeds the limits set forth in the program... ...



I'm also assuming that when the ECM see's the ON command for the exaust brake..... it will now hold the pressures up in the transmission to allow the power to be transmitted to the engine just like we see in the Allison World Transmission that's in the mid-range trucks.....



As we see these truck pull larger and larger loads, they will exceed the ability of the brakes to stop the load... . it's only natural that the engineers look to other methods to absorbe that energy and hold costs down..... after all, its cheeper to sell the customer an exhaust brake on those trucks that need the extra braking, than to build larger brakes on all the trucks they build... .



After all, its the money that drives the process... ...



Jim

 

[Carlton Bale]

Originally posted by jelag

There were some vendors that offered a lock up condition on the early transmission used in the second generation trucks... . it held the fluid pressure up to keep the torque converter and clutch packs locked up to transfer the power to the engine so that the exhause brake would help absorbe the energy.....



I'm assuming that the new transmission will have these features built into them. The ECM looks for the switch on the exhaust brake to be ON and when it see's the ON condition, will activate the exhaust brake at the required time..... This is when the engine is at idle and now per Carlton when the cruise control tell's it come on when the truck exceeds the limits set forth in the program... ...

Jim, that seems to be an accurate summary.

 

[Bill Stockard]

Jim & Carlton,



Thanks for the very informative posts. We learn from posts like you just wrote.



I am one of those considering the 48RE on my next truck, but only if it is exhaust brake compatabile.



Those of us who tow/haul with diesel engines at the truck's maximum GVW and/or GCW ratings in the western states must have additional braking on long steep downgrades for safety. Engine exhaust brakes provide this additional safety margin.



Bill

 

[DBVZ]

Jim and Carlton,



Back to my earlier question, from what Jim wrote (and Carlton agreed with) for the e-brake to work effectively, the ECM must know the e-brake is activated, and the ECM must notify the transmission to stay locked during e-brake operation. Does the Jocobs Brake, or PAC Brake have a sensor connection that is integrated with the ECM to do that, and does the transmission respond to that? That feature would not be needed for the 6 speed, so how do we confirm the e-brake by Jacobs or PAC etc , and the 48re, have been designed to work together? How do we know for certain the ECM will know the e-brake is activated, and will know to tell the 48re to stay locked?

 

[Carlton Bale]

The Cummins/Jacobs brake is designed to work with the 48RE transmission. All integration work has been performed. We're just waiting for warranty approval from DC.

 

[jelag]

I have not seen the circuit for the new transmission... . however when we connect a PacBrake to a mid range truck with the allison world transmission, the tranmission has been programed to be used with an engine brake...



The input to the ECM is where it all starts... ... the driver turns on the switch for the exhaust or engine brake as the case might be... . this is nothing more than an input to the ECM... . once the ECM knows the switch is on, it than will control the transmission and engine/ehaust brake for best performance..... this mean it will activate the exhaust/engine brake as needed to slow the vehicle... remember there are several inputs... speed sensor, throttle position... . etc..... it becomes seamless... . when the engine/exhaust brake is needed, it also will hold fluid pressure in the transmission to hold the clutches and torque converter locked...



Normally the fluid pressure falls as the truck slows down..... holding the fluid pressure up does nothing to hurt the transmission in fact the high pressure helps keep the system locked up.....



On most of the Allison applications, the engine/exhaust brake will extend the life of the service brakes 3-5 times and leave enough extra braking power for long downhill runs... .



However most customers with the PacBrake system leave the brake in the "turned on" position all the time... ..... loaded or empty and its a matter of understanding how to touch the throttle to either let the engine coast or absorb power.....



On the 03 Dodge there are two connections... ... 1) connection from the off - on switch to the ECM..... This tell the ECM that the operator wishes to have the exhaust brake active..... 2) the ECM actually turns on the PacBrake Exhaust brake as needed based on the programing of the ECM.....



I haven't taken a look at the wiring diagram of the Jacobs unit... its on thier web sight... ... but I assume it uses the same input and output that we use... . as this is the standards set forth by Cummins... ... .



Cummins has a great relationship with PacBrake as well as Cummins... . its shares information to both companies... . PacBrake was the first company to design an exhaust brake... and the first company to combine the use of an exhaust brake and enging brake on the same engine... ...



I'm rattling on here..... let me close by wishing all of you a great weekend...



Jim

 

[DBVZ]

Ok. I just wanted to be sure that PAC was designing the system expecting it to work with the automatic transmission. But, if the ECM is in control of everything, and the DC programming actually does anticipate an engine brake with the 48re, it ought to be fine - right? If the ECM needs to know if the e-brake switch is on to do it's thing to properly activate the e-brake (any e-brake), then it ought to properly control the 48re regardless of which e-brake is installed on the truck.

 

[jelag]

DBVZ



<snip>



If the ECM needs to know if the e-brake switch is on to do it's thing to properly activate the e-brake (any e-brake), then it ought to properly control the 48re regardless of which e-brake is installed on the truck.



<snip>



That's the way we see it.....



Have a great evening... ...



Jim