Manually downshifting a 5-45RFE tranny or throttle downshift it?

[nascar72]

Hey guys thanks for letting me join the forum. I have an '03 Ram 1500 4x4 quad cab with 5.7 Hemi, 5-45RFE tranny and 3.55 gears. I'm towing a 24ft 5ft wheel camper RV that weighs around 7000 lbs cargo included. Been towing RVs for few years now and been doing it in 3rd gear (O/D off) everytime no matter what truck I was driving. So far so good. Now, I've been towing my RV camper mostly on hilly roads with quite some steep inclines and I've always wondered if I should manually downshift or go with throttle downshift? I've tried it once going uphill in 3rd and obviously loosing alot of momentum dropping from 65mph to 50mph at wich speed I decided to manually downshift in 2nd. Didn't like the feeling at all when it dropped in 2nd compared to when I kick it down with the throttle. So what would be the proper way to manually downshift and what would be the ideal speed to manually go from 3rd to 2nd or should I keep going with throttle downshift? And...when you manually put it in 2nd, witch 2nd does it grab? The "takeoff gear" or the "kickdown gear"? Thanks in advance for your feedback.

 

[BWL]

If its struggling to pull 3rd so you drop speed I'd shift it manual until you get to the top of the hill rather than put all that strain on things and generate all that heat shifting under load and hunting for the correct gear. then go back to auto. For all its bad press the 545rfe in my last truck worked just fine for a lot of miles and was still working well when I sold it. Does the 03' have a tow haul mode like my 06 did?

 

[nascar72]

Unfortunately it doesn't have the tow haul mode. Just the O/D Off mode. I wish I had it though. Mine has 120k miles on it. Had the fluid and both filters changed last year and runs great. As I mentionned above, I tried manually downshifting in 2nd when the engine started to struggle and it keeps giving a mild to strong bang when I manually downshift from 3rd to 2nd. Maybe my speed is too high or should I do that at speeds lower than 50mph and can the engine susbtain or endure 3500-4000 rpms for 1-2 miles?

 

[Smokeybear01]

The engine shouldn't have any problems pulling at 3500 RPM for a couple of miles. I've done much worse than that pulling overloaded trailers through mountain passes with a 2008 (5.7) and no ill effects. In fact, that truck never gave me a single problem unlike some others I've driven. That racing engine does give you pause though.

 

[crash68]

Maybe my speed is too high or should I do that at speeds lower than 50mph and can the engine susbtain or endure 3500-4000 rpms for 1-2 miles?

When towing a load with a gasser, you better expect to have the rpms up around the torque peek of the engine, with your Hemi it about 4400 rpms. The engine will hold together many miles just fine, it's the owners that freak out about it. If you want to be able to tow in the 2K rpms range, get a diesel.

 

[RVGuy]

When towing a load with a gasser, you better expect to have the rpms up around the torque peek of the engine, with your Hemi it about 4400 rpms. The engine will hold together many miles just fine, it's the owners that freak out about it. If you want to be able to tow in the 2K rpms range, get a diesel.

I towed my trailer home 800km in a headwind the whole way with the engine screaming at around 3000rpms for 8 hours.

I can vouch that the Hemi doesn't mind working at those RPMs for as long as you need it to. Your ears though? That's another story.

 

[Snake15eyes1998]

I manually drop mine into 2nd gear around 55mphish. Sometimes 1st around 35-40mph. I let my rpms scream at 4000-4500RPMS. All the way up parleys, here in Utah. Thats where all the torque is for our hemi's. As you shift into 2nd or even 1st. Let your foot off the gas just a little bit. It will drop onto 2nd or even 1st just fine. Then before you give her hell. Wait for the gear to fully engage. Your radiator temp will definitely jump, but not anywhere close to overheating.

 

[Marley]

Tow a 7500# trailer often in the mountains of VA and WV.

I often see 4500 and even 5000 RPMS by manually down shifting......Hemi's don't mind.

On the interstate in tow-mode, 3000 RPMS sounds ideal.

Only issue I have is loud duel exhaust when towing.

 

[jmd4100]

Tow a 7500# trailer often in the mountains of VA and WV.

I often see 4500 and even 5000 RPMS by manually down shifting......Hemi's don't mind.

On the interstate in tow-mode, 3000 RPMS sounds ideal.

Only issue I have is loud duel exhaust when towing.

I have the same issue[emoji1787] 24" straight through got wayyyy louder by the time I got to my destination from the time I left the house. Guess I broke her in right [emoji23]

Sent from my SM-N975U1 using Tapatalk

 

[grpht03ram]

What kind of engine coolant temps do you guys see on the 5.7/4.7 under load going up hills?

My temps will rise to about 225 while under load uphill then come right back down to normal on the downhill side.

 

[Snake15eyes1998]

What kind of engine coolant temps do you guys see on the 5.7/4.7 under load going up hills?

My temps will rise to about 225 while under load uphill then come right back down to normal on the downhill side.

I would have to look again, but if I remember right. I think mine will jump up right around 215ish. Then drops right back down.

 

[grpht03ram]

Anything past the halfway makes me anxious. I wish Dodge had put a 2 row radiator in all the 3rd gen trucks.

 

[Snake15eyes1998]

Anything past the halfway makes me anxious. I wish Dodge had put a 2 row radiator in all the 3rd gen trucks.

Mine doesn't go past the half way mark. It stays right on the half way mark( while towing up hills) or just below it( not towing). If yours is going past the half way mark, I would say, you're truck is running a little hot. Hotter then normal. I would check your fan clutch,coolant level, etc, also look at TOWING IN O/D OR NOT threads. If you're RPMs are low while towing up hill or you're engine is lugging. You're engine can heat up. Those RPMs get the coolant moving and you're fan going. Really bringing it some CFMs. Plenty of threads that talk about this in towing. Good luck man

 

[TheEnder]

What kind of engine coolant temps do you guys see on the 5.7/4.7 under load going up hills?

My temps will rise to about 225 while under load uphill then come right back down to normal on the downhill side.

All depends really, 220-230 is the highest i’ve seen her. Transmission temps are at around 190-200


Sent from Blue Onyx

 

[tron67j]

Couple thoughts:. 1) do you have larger tires than stock ones for your truck; 2) have you weighed your unit full loaded at a truck scale; and 3) what type of fifth wheel are you towing? You could be over your maximum towing capacity with that set up. Note that trailer dry weight is from factory and dealer add ons such as extra awnings, propane in tanks, and other things will dramatically increase the weight further. Before looking for a fix that may not be found, get your fully loaded, including people and pets, rig weighed.