Hi guys, first post here. Been lurking for months and finally registered.
I'm having problems with my 07 5.9 Mega Cab.
I bought the truck used with about 55,000 KM on it. The trans. never really felt right in my opinion so I had it in to the dealer for service. They said it just needed fluid and filter change and the bands adjusted. That was Feb 08. In Sept 09, the dealer finally had to rebuild the tranny. I've had it back in almost every month since. The latest problem is that the truck doesn't want to downshift unless you stab the pedal 2 or 3 times. Sometimes I have to manually shift it into 2nd. The dealer has had it again and says they can't find anything wrong. Had a mechanic friend drive it and he figures it might be a software issue. Said it seemed that the trans was hitting 3rd then immediately into 4th. I know next to nothing about the actual workings of an auto trans.
I've been reading for the last 2 days on how wonderful the 48RE is and I'm at my wits end trying to figure this thing out. I'm tired of being passed by 18wheelers uphill. I tow a Jeep that with trailer weighs about 7200lbs.
I have 35s on the stock 3.73s which I know will suck some power but the Cummins shouldn't even notice 7K behind it. Tried the Smarty JR towing tune last time out. Power was definitely better but the trans can't seem to get it to the ground properly.
If I can't get this thing figured out I'll be looking at a 2010 replacement. (last resort).
I've been thinking about a Gorend but if its not the actual trans, spending $4K on another trans might not help. Nobody seems to believe me when I describe the problem. Trucks not throwing any codes either. Am I losing it or.....?

Any help is appreciated. Going into a different dealership Tuesday.

Brett

 

48RE is a pretty good trans when bilt correctly. Georend is the only way to go. A valve body and converter might fix all your issues, but I am not a tranny guru.

Tobin

 

Goerend builds a excellent transmission. Worth every penny ! Shifts are firm and quick. Gets power to the ground. Super smooth ! I pull 16000lbs and it is day and night difference between the Goerend and my stocker. It just works !

Daves crew is busy but they always managed to call and answer all my questions. Dave is very very knowledgable ! I like my new trans so much I ordered another one for my father in laws truck. Nothing but good to say far !

 

I would say give Dave a call @ Georend's. I have the 06 Mega with the 48re. My stock T/C went at 40k, and then the dealer did something to the tranny when it was in for work. My truck would not down shift at all. After a rebuild it just never was right. Last week I had a 3 disc T/C an
constant presure V/B and several other parts. I have 3k into it. Going to tow about 4k here in about an hour. My tranny now has a firm shift and I am running about 600 rpm lower than with the stock.

Dave is a great guy, he will build to suit for what you plan on doing with your truck.

 

So the truck's at a different dealer today. They still can't find anything out of the ordinary. They have talked to a Chrysler tech and they wanted to know how much weight I'm towing. They say that 7100lbs might not be enough for the truck to know to downshift. Suggested to try towing with the OD off.
What do you all think?
Thanks for the previous suggestions too.
Problem is if I let it go and not downshift I hit 1300+ on my EGTs pretty quick.
Truck has an AFE Stage 2 intake (I think, can't remember now) and a magnaflow turbo back exhaust. As mentioned I tried the Smarty Jr Tow tune last time out too. Adjusted for the 35s as well.

Brett

 

when im towing and mine starts ******* in 4th uphill, i hit the OD off button, top the hill and change back to tow haul.......works well enough

 

I have a Georend transmission full tilt with billet input shaft, billet output shaft, billet fly wheel, and although it was not cheap, it was worth double the price I paid. Changed the entire driving experience and now that I have over 120,000 miles on it, not only is it great performance, but it lasts as well.

Dave is very knowlegable about the 48RE and many other transmissions as well. He is patient with questions, (I know I asked many) and his product is top quaity. Every torque convertor, valve body, and fully assembled transmission is dyno tested for performance before it is shipped. He is about as nice a person as you will meet.
I drove from Georgia to St. Lucas Iowa to have him do the install, and two years later I was in the area and asked him to check it out to make sure it was all working well, and he took it for a 30-40 minute drive and stated it was working just fine. Ask around, you will find there are many who will verify that his customer service is what we all dream of.
That said, there are many fine transmission rebuilders who have many happy customers, but my experience is with Dave Georend.