Hey all!

New to the forum but not new to diesels....just purchased my second 04 1/2 Common Rail and work for a major truck manufacturer as an engine rep, so I know these Cummins engines really well.

However, what I have noticed with both of my Common Rails is how the throttle stiffens when putting the truck into reverse and stays that way in forward gears, raising the 2nd gear shift limit until you get about half throttle and then something "clicks" in the throttle and it goes back to normal throttle tension and shifting. My first Common Rail I got in 2006 with only 45k miles on it and second one I got with 225k on it and they both do it.

Problem is that no one, not even my cousin (that owns a transmission shop) says that they have ever noticed the issue. Now that both of my Common Rails have done it, one would think that it's some some of intentional design when backing but I have never confirmed nor seen any mention of it on the Internet or in the Owners Manual.

And yes, I have already gone through both trannies and installed the governor pressure solenoid, transducer, and band adjustment for the 1-2 shift issue that they both were experiencing but the pedal issue stayed the same.

Both have the earlier version of the 48RE with the TV cable. After digging into it a little further, it appears that the transmission valve body is pulling back on the TV cable when putting it into reverse, hence the difference in pedal feel and delayed shifting.

What I want to know is if the rest of you get this and if anyone has an explanation for it?

Thanks!

 

Never heard of this! the 06 uses a TPS on the pedal so there is no way for you to feel anything through the pedal! 04 not sure about that one someone else will chime in!

 

04.5 has cable runs out and attaches to the tps assy. under the driver batt. tray. Could be a linkage issue. Have you tried pulling the pan and have somebody shift trans and see if something is hanging up?

 

No, the TV cable runs directly from the throttle linkage directly to the transmission. The TPS cable you refer to goes under the battery tray is also for the cruise control.

Yes, I have had it apart when I serviced the tranny on my first 04.5 a few years back and checked this one out when I serviced it last week and everything is free. You can also move the cable through its travel where it attaches to the shifter arm on the transmission. If it were a cable issue, then it would happen all the time, which it doesn't...only when backing up. However, what caught me off guard with my current truck was that the throttle would stiffen and then the truck would downshift into 1st really hard when coming to a stoplight but only did it when the transmission was hot (was towing four motorcycles to Arkansas). I had only had the truck a week, so I went straight in and replaced the governor pressure solenoid, transducer, and adjusted the bands and the throttle and downshift issue has gone away. I only get it now when backing up

Just based on the fact that both of my trucks have done it seems that Dodge intentionally made it do this maybe to make it harder to give excessive throttle when backing up, especially when hooking to a trailer? Who knows. Strange that I have had two trucks do it but I can't really find anyone else that has noticed it.

 

The problem is a failure in the TV valve on the VB. It is not something that is intentionally done at all. This is a known issue and Sonnax has a repair kit specifically for it. Any pre-05 transmission all the way back to 1965 can and has had this issue, hence the fix.

 

I saw that the other day on Sonnax's website but didn't think that it applied to this issue. I'll look at it again. Thanks!

 

Any time you have a hang in the throttle like that check the cable first for free movement. They casn fray and cause issues but it should be all the time. If the cable is good it is almost always the TV having a groove worn in it and hanging at a certain point in the throttle advance.

 

Cable moves freely and doesn't appear to be frayed. I would also agree that the TV valve is hanging since the truck has 225k miles on it but question if it's this since my first Dodge only had 45k on it when I bought it in 2006 and it did it, too. Do you know if it can happen to low mileage vehicles, too?

 

Yep, there is no mileage requirement for it too happen. The problem was a QC issues with tsome of the parts used in the VB. Those could be scattered across many years and there is no telling when and where it will happen.

 

Figures that I end up with two that do the same thing and no one else seems to have noticed it much. Just my luck. LOL

Thanks for the help!