Engine/Transmission (1994 - 1998) ECM Reflash Question

[Dave Remillard]

I recently became aware of a TSB to reflash the ECM to change shift points on my automatic transmission. The TSB # is 21-04-95. I called my local dealer to ask about the cost etc. I was told that there are actually two reflash's that need to be done, and each would cost $75. 00 each. Since I have a zero trust for this particular dealer I would first like to know if there really are two TSB's, what would be considered a fair fee, and lastly, if any of you have done this, is it worth it. Thanks

 

[Joe G.]

You had better check the years that the TSBs refer to. You have a 47RH transmission. All the shift points except OD and torque convertor lockup are hydraulically controlled by a fly ball type governor. Later trucks have a 47RE that has shift points controlled by electronics.

 

[Dave Remillard]

Hi Joe... The TSB actually had seriel numbers for the ECM's that applied and mine match up to those numbers. Appreciate the caution however.

 

[Joe G.]

That's kind of strange. I cannot find anything in my '95 service about an ECM. The box the controls the transmission is a PCM (Powertrain Control Module). It is mounted on the firewall behind the air cleaner box. The only connection between the PCM and the transmission is for the OD lockout solenoid and the torque convertor clutch lockup solenoid. This connection is done with a three wire flat connection. The other wire is to 12 volts ignition on.



The 47RE PCM connects to the transmission with a round connector. I think it has 10 wires.



Basically, if you are trying to adjust the shift points for the 1-2 and 2-3 shifts there is no way to do it electronically for a '95 47RH transmission. If that dealer is trying to sell you a reflash to correct these shift points I would be very very suspicious. Check the connector. If it is a three wire connector it's a 47RH. It's on the driver's side of the transmission above and to the rear of the shift lever. There is a round connector on this transmission that is used for the starter interlock. It is directly behind the shift lever just above the pan. It also has three connectors.

 

[Dave Remillard]

My mistake as I thought the box behind the air filter (on firewall) was called the ECM (Electronic control module). And the box on the drivers side fender was the PCM. Now I've got that straight. The point is I am talking about the box on the firewall. The TSB is to change the shift point mainly for going into OD lockup. Presently it happens at 45 MPH normal driving conditions and is just plain and simple to soon. In MHO should be no sooner than 50 MPH. That is what I believe the reflash does. Just hoping to find out if anyone else has had this done, and if so, did it help. Again Joe... Thanks and I will take a look see at the connectors as you suggest. I know some would suggest just use the button on the dash and don't let it shift in OD until 50 MPH, but I guess I'm sort of inclined to think that in todays age, we shouldn't need to control shift points manually when we have an automatic. I for one thought that is what automatic stood for. Anyway, just me.

Dave

 

[Howard Durand]

I took my truck to the local dealer for a re-flash but found that mine is one that can't be updated. He was only going to charge $30 for the job.

The OD and TC lockup shift points are a major concern with the 47RH and are the ones that would be affected by the re-flash.

I don't understand how they could charge you for two when the entire update should be accomplished with one download from DC.



Find someone who is not quite so greedy.



I have been able to adjust my TPS to get the OD shift point up into the 55 mph range but it called for a drastic modification of the TPS.

 

[DCTECH]

wE CHARGE 1/2 HOUR TO REFLASH A PCM, ON A 95 IT IS REFLASHABLE TO RAISE LOCK UP SPEED IF YOU HAVE THE RIGHT PCM NUMBER.

 

[Dave Remillard]

Thanks for the feedback. I now have a couple more questions. First. . Howard, care to detail what you did to the TPS to get the results you have. I've adjusted voltages and cleaned the dang thing but still have the typical problems. Second ? is for DCTECH or ??? I see your in Michigan, me in Oregon, thus we can't do business. Just wondering are you a dealer, or can a reflash be done by privetly owned repair shops? BTW, my seriel number is correct for doing the reflash if I can find an honest place to do it for me.

 

[Joe G.]

I did like Howard. Modified the TPS mounting holes so I could turn it more. That was enough to get my OD and lockup shift points where I wanted.

 

[Howard Durand]

This is a picture of the back side of the TPS.



Be aware that this is a pretty radical modification. I have a spare TPS so figured I wouldn't lose much if this didn't work.

It did work for me.

I was only able to get about 0. 9 volt with just the spacers removed. I am now getting 1. 3 volts which moved the OD shift up to between 55 and 60 mph when the truck is cold.

As it warms up the shift point drops back some.

 

[Bob4x4]

Dave,

The flash is a dealer only item. Cummins can flash the ECMs except the 3rd gens. The flash is worth doing but only one is required. The new flashes contain all the previuos upgrades that are still known to work. I do adjust the TPS on the high side of the spec... . it does work a little nicer for most trucks.



Bob

 

[Howard Durand]

Here is the front view.

 

[Howard Durand]

Here is the plate that holds it in place. I used the original bolts and the inserts as spacers to make sure I don't put too much squeeze on the TPS.

 

[Dave Remillard]

Thanks guys. Howard, that is radical alright, but sure seems reasonable. I have wobbled out the mounting holes already, but looks like I can get a bit more carried away. Right now I can only get 1 Volt max at idle position. Glad to hear Cummins can do the reflash. I'll give Cummins NW here in Portland a call and see when I can get it taken care of.

 

[Bob4x4]

Sorry for any misunderstanding,Cummins can flash the ECU not the PCM.



Bob

 

[Howard Durand]

Dave,



Be careful when you get close to the throat of the connector. You don't want to expose the wire that is molded into it.



I compressed the size of the spacers and am getting 1. 3 volts now.

When first starting out, with everything cold, the shift point into OD takes place at about 60 mph.

After everything gets warmed up, it drops back to 50 to 55 mph.

I haven't towed the trailer yet since making these changes but am confident that it will be better.

With the DTT valve body, TC lockup doesn't occur until I lift the accelerator and allow it to shift and, since I got the TPS voltage up, the TC doesn't disengage when I take my foot off the accelerator. It stays locked until about 1100 rpm. This is going to be real nice when using the exhaust brake.

 

[jimk]

I have 1. 3 volts at idle an it goes into overdrive at 45. I guess it is just my luck . I have never be to happy with it an that only adds resolve to be rid of it. I did not intend on keeping it but it would have been nice not to have used the lock out button once in a while. Thanks any way HOWARD, as it is nice to see some one who wonts to help out. Regards Jim

 

[tgrfan2]

I tried to reflash my 95. The dealer said I needed a new PCM. He did not charge for the attempt. I decided to install a toggle switch instead per TST. This is not the mystery switch, but only interrupts the ground so you can delay lockup. Since you have a temp gauge it will cost you about $5 to try it. It has worked fine for me for 90K. I usually just leave it in the unlocked position in the city and run with OD off. I have never had any trouble with overheating the transmission except in severe stop and go driving pulling a 9K TT and I wasn't going fast enough to lock up the transmission long enough to cool it down.

 

[Dave Remillard]

Thanks for clearing that up. There are at least 4 Dodge dealers in the area, maybe one of them will be a bit more honest in their pricing for a reflash. I know... dealer and honest in the same sentence just doesn't seem to go together.

 

[Howard Durand]

I have a switch that allows both manual lockup and manual unlock and use it the same way as tgrfan2. I only use the manual lockup for the exhaust brake.

I usually don't mess with OD, just let it do it's own thing. Even around town. But I keep the TC unlocked to prevent the chugging and jerking that occurs when it locks up and the rpm drops. The problem is the same when driving heavily traveled 2 lane roads.

I was getting some horrible noises occasionally when I would be accelerating trying to get rpm up then something happens that I have to get off the accelerator real quick. I was thinking I was slipping the TC but, after some reading here on the forum, I am convinced now that noise was the turbo barking. Under the same circumstances,but keeping the TC unlocked, that doesn't happen.