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Discussion Starter #1
Got me a 2500 gasser. Got some questions for those who tow big loads in Hemi's like I plan on doing. Engine seems to definitely have the balls to get the trailer up the hills (when rpm is appropriate) and the truck brakes/suspension are great. It's the auto 55rfe that needs attention. Supposedly my truck's computer is unique so a tuner isn't really an option (info on this)? Basically the issue at hand is when pulling hills the trans goes down to third gets to wanted speed and then shifts back to 4th which is not an optimal rpm range for climbing hills. Any way I can make it stay in 3rd when climbing hills? People are going to say go to 4.56 and that would be great but to do that would probably cost me more than I payed for the rig. Tires are 265/70r17 stock size bfg ko2 ats. Trucks got 238k so tired but runs really good and shifts really good. Im all ears if yall got any other future tow mods that don't cost a fortune for these trucks.
 

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could drop tires size but gearing would be a lot better
i was told on my 03 ram 1500 that a tuner won't change the shift points at all (from a service tech )
i also have the hemi in it running 35 inch tires ( but i am planning t do a gear swap to 4.88 )
 

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I can't remember the shift configuration on that year Dodge, I have found with my 15 to lock out 5th and 6th while towing heavy (10K fifth wheel camper)
That's the sucky thing with the Hemi, no power till it's revving.
Do you have the tow mode on the shifter?
One thing on it up shifting, don't let off until it shifts on it's own, in other words don't lift your foot so it can shift just to have to get back in it. It will scream until it needs to shift. At least that is my findings but I have 5 year 100K warranty on my power train. :flipoff2:
Any idea what gears you have?
 

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Discussion Starter #4
The truck's got 3.73s on it. Read last night that 2nd gear was 1.67 (odd for a trans in a hd truck but oh well) so I plugged that into an rpm calculator and around 55mph I hit 4000 rpm in that gear, tested it and thats about right. Next time I tow 6k+ with the truck and find myself struggling on the hills I think I'm going to throw it in 2nd and see what that does for me. Heard of others doing this too on some other forums after some searching.
 

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I had that exact same truck with that same problem. Now way to hold in 3rd, shift to 4th then no balls for hills, then it would drop to 2nd and scream. I tried the Superchips programmer and added the custom trans tuning software. It really didn't solve the issue. I played with tire size, that wasn't it either. I added that Somex trans line pressure booster in hopes of something magical. Nope, no help.

I just learned that cruise control while towing was useless and to plan about a mile in front of any hill. Slowly speed up and let it slow back down as you crest the hill. It kind of became a game to keep the trans from shifting. Unfortunately I was just a huge annoyance to every other vehicle. They passed me going up hill, I passed them going down hill.

Liked the truck, but the lack of trans control was a big part of the decision to sell it.
 

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actually re-gearing the diffs is the way to go on a 545rfe. its technically a 6 speed but the "3rd" gear is actually a passing gear between 2nd and 3rd called 2nd prime. So in all actuality you have a old school 3 speed torqueflite with 2 OD's and a passing gear between 2nd and 3rd. complete shit situation for towing. The only thing you can do to compensate is to re gear.
 

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I had that exact same truck with that same problem. Now way to hold in 3rd, shift to 4th then no balls for hills, then it would drop to 2nd and scream. I tried the Superchips programmer and added the custom trans tuning software. It really didn't solve the issue. I played with tire size, that wasn't it either. I added that Somex trans line pressure booster in hopes of something magical. Nope, no help.

I just learned that cruise control while towing was useless and to plan about a mile in front of any hill. Slowly speed up and let it slow back down as you crest the hill. It kind of became a game to keep the trans from shifting. Unfortunately I was just a huge annoyance to every other vehicle. They passed me going up hill, I passed them going down hill.

Liked the truck, but the lack of trans control was a big part of the decision to sell it.
So let it scream in 2nd. :confused: I did 2 trips to Moab in mine (same truck, but 33's and 4:10's, crawler on a car hauler) and would crest the mountains at 70mph+ over 5 grand, passing everybody.

[approaching mtn] cruise on 70mph
[foot of mtn] tap brake pedal/disengage cruise, push accel. pedal 3/4 to floor
[on bottom of mtn] hold 3/4 pedal, wait, speed dropping slightly
[half way up] still 3/4 pedal, just downshifted, speed picking up
[3/4 way up] LET IT EAT--- GET SOME--- move to left lane and pass people
[before top of mtn] now 7/8 pedal, glorious roller hemi sounds, holy shit we're actually speeding, these headers sound like Steve Vai playing amazing grace to St. Peter!!1!

:flipoff2:
 

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Discussion Starter #9
Currently get 10.5mpg empty. According to calculators with the 545rfe's .67 od gear and my 31.6" tires I'd be at about 2450rpm at 75mph with 4.56 gears. This would be sweet don't think mpg would suffer too much cause it already sucks terribly. Anyone have 4.56 gears w/ stock tires? Can yall confirm rpm?
 

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A few years back I was following several forums doing research. The 1500 guys can't say enough good about running the 4.56 gears, and tires right around that size. They claimed better fuel economy up to 75 mph too.
 
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