Manually shift with an automatic?

[Tonkatoy77]

I manually shift my Duramax on hills. I think a lot of you guys would too if you had an EGT gauge. If I let the tranny "do it's thing" my EGT's will go clear up to 1300 degrees before it downshifts. If I downshift as soon as I hit the hill, it doesn't even hit 1000 degrees. Also, once it downshifts I want it to stay in that gear until I reach the top of the hill. If I let the tranny "do it's thing" it will try to up shift as soon as it has a chance, and then have to downshift again before I get to the top.


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[RubyDually]

X2 here..

I use the T/H mode usually in 5th where I'll manually downshift if I see the exhaust temp going over 1000* and if the transmission is going to constantly shift up/down on the hill.

Like Tonkatoy77 said.... this way the exhaust temps stay below 1000*

I also prefer to stay out of 6th gear when towing @ 100 kph (63 mph). In 5th gear the rpm's are around 1800-1900 RPM's with temps in the low 600's. Lugging along in 6th the RPM's are down to 1600 and temps are often in the 700's on the same stretch of flat land. Plus on the small hills the transmission will want to shift more often when keeping it in 6th.

[bruane]

I note that a lot of people that vote in favour of manual shifting have earlier truck model i.e. less than 2010. My 2-13 F150 ecoboost has all kinds of sensors that measure the lateral and vertical movements and feed the systems that manage the transmission and in turn manage the Tow/Haul process. As one member commented measuring slope is a matter of perception. This equates to a pilot blind flying. The pilot has to trust his instruments not his senses when flying in a cloud or he or she will soon be disoriented.
My advise is if you have a late model with Tow/Haul mode and good display systems then trust the on board computers before your perceptions. Its easy going up hill with cruise control but down hill with 6/8% grades and a turning roads as in the Canadian Rockies the truck performed flawlessly and only need a quick bleed on the brakes when warning signs for 20/30 mph on some turns came up. There is more computing power in one of these trucks than on board of the whole of the Apollo systems and a better failure rate than them. The marvels of modern mass produced software!
I have been involved with computers in all kinds of applications since 1967.

[atcla]

Well, sounds like good arguments for manual and automatic use. I guess it all depends on your equipment. I will continue to trust the automatic unless it feels like it's struggling, which I have noticed in cruise control on long climbs...it seems a little slow to react to the climb. And of course going down making sure to downshift! This really is the best forum, I learn so much from all you people that have been doing this for years! Thank you, I only have 1 year under my belt so far!

[donniedu]

Yea, I use the gear selector button a lot. Especially if I am climbing hills. Combined with tow/haul mode and the factory EB I am able to have total control at all times and keep my motor in the optimal power range.

[Tonkatoy77]

I guess my question to the people saying that the ECM, TCM, and BCM are smarter than the driver, why even have the manual mode?


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[checkmate99]

I agree with micpib1. I tried both methods with my 2010 Ram Hemi (5 speed auto w/overdrive). Even in tow/haul, the trans spent too much time searching for the right gear, and heating up the trans temp. Manually shifting keeps the engine in the right power zone, and the trans much cooler. It also eases my nerves by not worrying about all that heat, which is a trans killer. I believe you received some good advice.....you can take it or leave it!

[kandl]

Originally Posted by bruane

As one member commented measuring slope is a matter of perception. This equates to a pilot blind flying. The pilot has to trust his instruments not his senses when flying in a cloud or he or she will soon be disoriented.

Bad analogy. IFR engaged in IMC implies that the operator (driver/pilot/stick actuator) is not looking out the window. Fellow RVers, your TV may have all the latest bells and whistles but I urge you to look out the window!

[Jim34RL]

Originally Posted by atcla

So we had our 2010 RAM 3500 Cummins Diesel in for service at our favorite mechanics shop. He told my wife since we are towing a 37 foot 5th wheel that I should be manually shifting the gears. I understand when going down a long hill to downshift to save brakes, but to always manually shift? Has anyone heard of doing that? Seems like a lot of work on normal roads.

I have done this since new on my 2008 RAM with the Cummins and the 68RFE auto. I try to keep the engine rpms between 1500 and 2000 for best engine performance and fuel economy. If you do not the engine will lug in either fifth and six gear at 40MPH and lower the engine rpms are under 1300 could be as low as 1100.

The way that I operate my truck is to lock out 5 and 6 gear in town and shift up to fifth and six as needed on the highway with and without the trailer. The exhaust brake is on 100% of the time regardless if I am towing or not. This keeps the soot level down in the turbo and from getting the dreaded P2262 and P061A engine codes-turbo issues.

I will also downshift when pulling up a long steep grade with the trailer attached to fifth gear to raise the engine rpms and cool the EGT's; I do not like them above 1100F.

[Filterman]

Here's my solution and it works pretty well. We do a lot of tough hauling in very mountainous terrain. Run of the mill highway stuff, auto with tow haul turned on works well, until you get into lower gears. When I get into severe up and down terrain , I shut off tow haul and shift manually. There are certain situations that ( like all computers) the auto in tow haul just isn't practical. I pull with gas so no engine brake. The two haul always wants to keep shifting you down to the point the ROMs are too high and the gear too low.

[mikemc53]

OK, I'm totally new to this so I have few opinions but always curious as to how others handle things.

I have one of the older units (2004 Dodge Ram 3500 Quad Cab, 4X4, 5.9L Cummins HO, auto trans (48RE)). The trans has been completely redone with BD triple disc billet torque converter, new valve body and oversize oil pan. From what I can gather the tow/haul mode in my truck is not really linked to particular sensors but is basically a manual lockout of overdrive. So, in essence, not really a "smart" tow/haul mode.

Would manual shifting make sense with this one or is it still recommended to let the tranny do it's thing?

[Jeff in NC]

Originally Posted by mikemc53

OK, I'm totally new to this so I have few opinions but always curious as to how others handle things.

I have one of the older units (2004 Dodge Ram 3500 Quad Cab, 4X4, 5.9L Cummins HO, auto trans (48RE)). The trans has been completely redone with BD triple disc billet torque converter, new valve body and oversize oil pan. From what I can gather the tow/haul mode in my truck is not really linked to particular sensors but is basically a manual lockout of overdrive. So, in essence, not really a "smart" tow/haul mode.

Would manual shifting make sense with this one or is it still recommended to let the tranny do it's thing?

I have a similar tow beast...2005 Dodge Ram 2500 Quad cab w/ 5.9 Cummins with a built 48RE and Smarty S06-PoD. I am towing pretty heavy. When ready to go camping I am at 19.5K combined.

The 48RE is just the old 727 Torqueflite with an OD unit bolted to the back. So technology wise it s pretty old. I have learned that it can be built relatively inexpensively (when compared to other transmissions) to withstand more than I can ever imagine.

The shop that built my transmission advised just that. Do not lug the engine. Third gear can handle way more torque than the OD unit. Higher engine RPM will also make more line pressure to prevent slipping of the clutches.
Since 2005 was a weird year that Dodge did not give you the ability to lock out OD (just tow/haul mode for 2005. 006 had both) I had to add a BD OD lock out kit to give me that function. Higher RPM when climbing a grade = lower EGT as well.
I will typically lock out OD until I am going faster than 55-ish. I have found the need a few times to manually downshift to second in traffic but generally do not.

If you do not have gauges for EGT and transmission temp I would suggest that you get them. I use the info from them to adjust my driving style accordingly

[Gitiup]

I only manually shift in my Vette, I let the diesel do the talking.

[Jim34RL]

Originally Posted by mikemc53

OK, I'm totally new to this so I have few opinions but always curious as to how others handle things.

I have one of the older units (2004 Dodge Ram 3500 Quad Cab, 4X4, 5.9L Cummins HO, auto trans (48RE)). The trans has been completely redone with BD triple disc billet torque converter, new valve body and oversize oil pan. From what I can gather the tow/haul mode in my truck is not really linked to particular sensors but is basically a manual lockout of overdrive. So, in essence, not really a "smart" tow/haul mode.

Would manual shifting make sense with this one or is it still recommended to let the tranny do it's thing?

I believe that most Ram owners (Dodge no longer builds pick-up trucks) who have the 68RFE are the ones discussing the shifting technique at least on RAM’S. The reason is there are two overdrive gears in the transmission; 5th gear (0.82:1) is a single OD and 6th gear (0.63:1) is a double OD gear ratio. Truck will lug if in 5th and 6th gears in town.

With my truck and the 3:73 differential gear set with the LT285/70R 17 tires; at 30 MPH the engine RPM’s are around 1200 if I am in 5th gear. The engine seems to be lugging to me which is not good for a diesel. I toggle the switch to 4th gear locking out 5th and 6th gears the engine RPM’s are above 1500. The truck will still shift like it normally would but will not be able to shift to 5th and 6th gears. These are electronically locked out; tow/haul is not effected at all shift points are still changed when tow/haul is engaged.

[atcla]

Jim34RL, that's interesting. So if I use the +/- and set it to 4th gear, it will still be just like the norm except lock out 5th and 6th? Being fairly new to all this I'm learning a lot! Thanx!

[bob caldwell]

Originally Posted by Jim34RL

I believe that most Ram owners (Dodge no longer builds pick-up trucks) who have the 68RFE are the ones discussing the shifting technique at least on RAM’S. The reason is there are two overdrive gears in the transmission; 5th gear (0.82:1) is a single OD and 6th gear (0.63:1) is a double OD gear ratio. Truck will lug if in 5th and 6th gears in town.

With my truck and the 3:73 differential gear set with the LT285/70R 17 tires; at 30 MPH the engine RPM’s are around 1200 if I am in 5th gear. The engine seems to be lugging to me which is not good for a diesel. I toggle the switch to 4th gear locking out 5th and 6th gears the engine RPM’s are above 1500. The truck will still shift like it normally would but will not be able to shift to 5th and 6th gears. These are electronically locked out; tow/haul is not effected at all shift points are still changed when tow/haul is engaged.

X2

[Jim34RL]

Originally Posted by atcla

Jim34RL, that's interesting. So if I use the +/- and set it to 4th gear, it will still be just like the norm except lock out 5th and 6th? Being fairly new to all this I'm learning a lot! Thanx!

Yes that is correct. Now I would also run the exhaust brake 100% of the time. The only time not to use is when the road surface is slick say snow covered or ice covered. The reason is this keeps the turbo from sooting up and allows the slider ring to function correctly over time.

I could give you more but I am trying to keep this simple.

For more information go to Turbo Diesel Register. Com, the best site on the web for the Ram Cummins truck owner to learn about the truck. We are not a group of kids who are trying to hot rod the truck. We cover the first gen all the way thru the 4 gen trucks and the 1500 Eco diesel too. I have been a member since Nov 2007 will worth the $35.000 yearly membership fee.

[bob caldwell]

Kinda spendy, but.....

[atcla]

Thanx for the info Jim, I'm going to check that out!