Manually shift with an automatic?

[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.

[Todouble]

Wow! I do think he's wrong. Just make sure it's in tow/haul mode when towing and let the auto trans do its thing. You gotta love these service centers.

[Ford Idaho]

NO,NO DANG WAY!

The transmission control module is smarter than who ever told you to "manually shift" the auto.

Use the Tow/Haul mode and all will be fine, it's what I did with my 2010 in Colorado last year when coming down from Eisenhower tunnel.

[dmac1951]

He doesn't know what he is talking about. The 68RFE transmision is as good as anything thing out there. Put it in tow/haul and let her go. I do sometimes use the manual control (+ or -) to keep my 2500 from shifting into 6th gear. Use the engine brake if you have a diesel and you will need to gear down very little.

[panthercity]

On our trip to the West Coast last year, I would shift manually in the mountains if my EGT got too high. Otherwise, nope.

[NoviBill]

For anything but downhill let the transmission controls work. In tow-haul mode it will do the right thing. For downhill you may need to manually downshift to slow yourself (remember brakes will overheat and fail if applied for to long). For many new model vehicles setting the cruise on a downhill will tell the engine and transmission to slow you the the cruise speed.

[Papa GLS]

Have a 2500 Chevy Duramax Z71 & when I'm in the mountains or big hills I just use tow mode. When on relatively level roads I take it out of tow, put it in OD & cruise control. Never a problem. Has the Allison tranny & I believe it makes all the difference in the world.

[captnrick3]

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.

That's the craziest thing I ever head of. Ford Idaho is spot on, no way you can manually shift and do better than an electronic transmission control module. Only for down hill situations for sure.

[atcla]

Thanks for all the quick replies everyone! It sounded crazy to me, now I know it is!

[uphillracer]

I have a 2008 LR3 and it has a sport shifter. I learned to use it so I could stay in cruise control and just downshift on the uphills as needed to the gear needed. If I tried to use cruise with the 6 speed automatic it would spend way too much time in 3rd. Also, I go no further than 5th gear per service dept. advice. It all probably depends on the particular vehicle and its design for the job of towing.

[AZMac]

OK, and I know I will take grief for this, but, using your manual shift control is necessary for some conditions.
I have the exact set up (2010 Ram 2500 with the diesel and automatic transmission). I tow a CC Silverback with a dry weight of 11K + lbs.
Where I live, in northern Arizona, there are numerous hills to climb. I should mention that I have both turbo and transmission sensors and closely monitor the temperature of both.
When going up these hills (3 to 6 % grades), I will generally shift down to 5th gear. This, I have found, drops both the turbo and transmission temperatures. I hear what others are saying ...let the automatic function do the work, however, in my experience, it want always drop into a lower gear, which results in the turbo getting above 1,000 degrees, which I try to avoid.
Bottom line, it want stress the transmission either way. I just like being in control of things I can.

[mud yapster]

I have the 2015 Ram 3500 with 6.7L coupled with the Aisin tranny towing 18K I use tow haul and set the cruise. On rolling hills I thing it shifts to much but hay what do I know about the Aisin tranny shift patterns. I know it under warranty for 100K miles and it was a $2995 option. Let her roll and shift like she wants cause it doesn't slow down for any hills so works for me.

[grandpacsf]

I have a 2007 Ram 3500 with 6.7/auto and pull a 2013 Silverback 33RL. I always use the tow/haul and exhaust break, set the cruise at about 65 MPH and let the computers decide when to shift or slow down even on the I 15 Great Falls to Vegas and then to Phoenix. The only exceptions, I kick off the cruise on a long down grade where I like to start down hill at about 80 - 85 MPH. I rarely need to use the breaks! Even the "hole" between St. George & Vegas where the speed limit is reduced.


____________________________
Central SK.
2007 Ram 3500 4x4 SRW 6.7, Air-Lift Air bags
2013 Silverback 33RL, TrailAir Hitch, 4K Onan at the rear
RV usage - 130+ nights per year

[fvstringpicker]

With my duramax, I try to maintain 2000-2400 RPM on steeper/longer grades. I use manual to limit shifting to a higher gear and dropping the RPMs.

[frozen]

A 68RFE pulling a heavy load, in tow/haul, and in cruise will loose several mph before downshifting as it climbs long, steep hills. Then after downshifting it will burn a bunch of fuel as it recovers the lost speed. A manual downshift before beginning the climb will prevent that loss. And coming off a 10,000' pass without some manual intervention even with the exhaust brake activated will take a lot of foot-braking. I am very happy to have manual shift capability and use it a lot in mountains.

[bruane]

I have an F150 and it always runs in Tow/haul Mode. I have been through the Rockies twice and and go backwards across the Appalachians every year. Tow Haul mode with the electronic controls is a a major transmission and safety manager especially on the down hill stretches where it become basically feet off and let the controls manage the speed etc. No burning brakes phenomena!

[micpib1]

As a former truck/bus driver, I always shift my auto transmission to keep my RPMs in control. I have yet to see a computer that can shift my transmission in anticipation of a steep up or down grade. The computer will shift up/down when the RPMs get to high or low, I believe that keeping my 2013 Ram with a Cummins within it's normal operating limits will extend it's life just like my truck/bus Cummins motors. I do use the Tow/Haul Mode when I have a worthy load. Also, I live in a very steep mountain area and have followed to many RVs with out of control speeds for the terrain or I smell their brakes most of the way down the long grades. So I will continue shifting my auto and smiling while I drive past all of those repair shops... I hope. JH

[robbdrell]

Just spent the last month pulling my Rockwood TT with my Tundra 5.7 through the mtns of Colorado. Being from Florida I have no experience with mtns. My research on-line told me to just trust the Tow-Haul mode but on the long grades I felt compelled to down shift to 3rd and even 2nd gear occasionally for fear of not gathering up too much speed downhill and not using the brakes too much for fear of "glazing". So if I just waited out the Tow-Haul mode will it have eventually slowed me down to a safe speed or was I right to downshift to avoid a runaway situation? Just trying to do the the right /safe thing. Any suggestions are appreciated.

[micpib1]

Robbdrell, I believe you did the right thing, thanks. JH

[kandl]

Originally Posted by atcla

It sounded crazy to me, now I know it is!

Actually not so crazy. But less applicable for recent TV power plants that produce gobs of power and transmissions with more than six speeds. The logic has been touched on here and it is simply this: you can react faster to rising terrain than the PCM will because you can see it. Our Dodge pickmeup is pushing the envelope with our TT and sports the older 5-speed trans. While mountaineering, I can stay way ahead of the PCM on downshifts by manually performing same. That can translate into a 15-20 MPH top speed difference while ascending a 7 or 8 percent grade without pushing the engine into banzai mode. As for going down the other side, your brake controller should be commanding downshifts as required by simply giving the brake pedal a good jab.

Your mechanic is not entirely out to lunch.