04 vs 04.5

[p-Bar]

What do you mean not enough ram?

Not enough memory in the ECU. RAM= random access memory

 

[AH64ID]

Thanks.

Interesting, aparantly the auto needs a lot more RAM than the manual. It's only one more logic function, which is the locking of the torque converter.

 

[p-Bar]

Thanks.

Interesting, aparantly the auto needs a lot more RAM than the manual. It's only one more logic function, which is the locking of the torque converter.

John I followed that long thread from the start on Jacobs testing the brake on the Ram and getting Chrysler approval . The whole lockup deal is a sham.

https://www.turbodieselregister.com/threads/76813-48RE-Exhaust-Brake-Current-Status

 

[AH64ID]

What is the sham?

If the Trans is already locked on decel then what additional software is needed?

 

[p-Bar]

Just how such a big deal got made about the torque converter having to be locked up.

 

[cerberusiam]

The auto has a complete TCM module dedicated to it. Actually quite a lot goes on in the TCM:

TH algortithm along with standard shift algorithm
Fluid temp reading and algorithm to do something whne it gets to high or low.
Gov pressure reading and code to compare to a table along whith wheel speed
Gov solenoid settings table and code to compare against gov pressure readings and wheel speed
OD control and all its associated parameters and fail safes
Lockup control and all its associated parameters
On the 05 a whole alogrithm and tables for the TTVA motor


IIRC, the problem is not with the lockup, the problem is making sure it is ion the correct gear AND locked up correctly for EB operation. The TCM was missing the controls to downshift and lock the TC correctly based on what the Dodge engineers thought it should do, not that it did not work at all. I don't ever remember Carlton or anybody saying positively that the ECU did not have enough RAM, it was inferred that prior to 06 the ECU did not contain the controls to operate effectively with the EB. All they need to do to make the 05's work was change how the TTVA behaved when the EB was activated. The 04's were never going to get it because there was no TTVA to control and make the downshift work right.

There was even talk of a flash to fix that in 05 ECU's. Unfortunately it was all vaporware. No way was Dodge releasing a flash to retrofit older vehicles to use an EB because it would cut into sales of new vehicles. Conscious decision on Corporate's part to continue with planned obsolesence to drive sales of new trucks, and, bail on warranty of older ones.

 

[p-Bar]

Cerb this is from the thread Carlton started:

48RE + Exhaust Brake: Current Status

update 11-May-2005: The Jacobs Exhaust Brake has been warranty-approved by Dodge for use on 2006 automatic transmission trucks. All of the brake and transmission controls are integrated into the Engine Control Module and no external lockup-box is needed. Manual transmissions, of course, are approved as well.



Obviously, this brings up the question "what about older vehicles". We're still hoping to be able to release a software update for MY2005. Unfortunately, every last resource is devoted to upcoming production changes and the MY2005 request is pretty far back in the queue. I don't know how long it will be, but probably not this year. I tired my best to get a higher priority but was unsuccessful.



For MY04 and MY04. 5, a compatibility issue was identified. These vehicles have a different revision of the Engine Control Module with less memory and the new software simply can't fit. Warranty approval is not possible with these vehicles anyway because of the thrust washer (discussed in this thread). The software may have offered some additional protection for those forgoing warranty approval and installing a brake anyway, but it is not feasible given the memory limitations.







update 5-Feb-2004: Cummins is still working closely with the 48RE transmission group to make the 48RE compatible with the exhaust brake. One hardware change went into transmission in January and another is planned for February. We are also working on a second round of software changes that require extensive testing. I won't make any promises. We've encountered several unexpected issues along the way and there could be more. I'll post as soon as I have more information.







07-08-2003: Below is the information that was sent to Cummins Distributors. We tried, but couldn't get warranty approval for the MY03. 5 48RE. I'll let you know as soon as I can.



Extensive testing has been conducted of the Dodge Ram 48RE automatic transmission with an exhaust brake-equipped Cummins Turbo Diesel. Dodge and Cummins have identified vehicle control system and hardware changes that are necessary before factory approval is given to this application. For this reason, use of any exhaust brake on a 2003 Dodge Ram with an automatic transmission will not be approved.



Dodge and Cummins are working to approve the use of an exhaust brake with the 48RE automatic transmission during the 2004 model year. The strong level of customer interest for an automatic transmission and exhaust brake combination is appreciated. Dodge and Cummins will jointly continue to pursue a product offering that meets the reliability and performance expectations that customers have come to expect.


__________________________________________

Carlton Bale

Cummins Product Engineering

Cummins Exhaust Brake Official Web Page

Installation and Operators Manuals for Cummins/Jacobs Exhaust Brakes

Last edited by Carlton Bale; 05-11-2005 at 09:48 AM.

 

[cerberusiam]

Like I said, the 05 need a flash to control the TTVA correctly and it would have been fine. Never happened for the stated reasons.

The 03 and 04's were never going to get approved, not with the manual TV control. The TTVA motor was the key to making the down shifts and the TC lock adequately when the EB was engaged. By default the TTVA motro backs TV pressure off whe the throttle is released and that will not allow donwshifts to happen correctly nor adequate pressure on the TC cltuch for max loads on a stock trans. Add a shift kit and a better TC and all these problems pretty much disappear but that is not the corporate way.