I bump my transmission into manual mode all the time. In addition to mountain driving, the Interstates around here have a lot of short exit ramps and cloverleafs where speeds go from 75 to 25 or a full stop in a hurry.
"Don't believe everything you see on the Internet" - Abraham Lincoln
Do it all the time with auto transmissions, have been for years. Just have to take it out of "Drive" and use the manual or sequential mode to limit the upper gear. May still need to use the brakes, but not as much. Newer electronic controlled transmissions that I've used will downshift themselves when going down a hill when using cruise control.
Just be careful on icy roads. There is no clutch to slip/feather when down shifting with an auto trans, dropping the trans a gear can break loose the drive wheels and put you in a skid. Better off using brakes (gently!) on ice.
And for the earlier thread on engine braking vs down shifting - you get more effective engine braking by down shifting.
Modern trucks and SUVs with towing packages are great at automatically keeping the vehicle in the right gear on steep grades, both up and down.
Until they break, which happens more often now with transmissions than 10-15 years ago, because they are so complicated now. They are marvels of modern engineering, but for the most part, they aren't as reliable as the old mechanical four speeds of not so long ago yesteryear.
Cincinnati is a hilly city. It seems like everywhere I go, I have a steep hill to deal with.
I used to go through break pads like water. As I got older I resorted to downshifting on hills. I probably have 1/4 the number of brake pad replacements.
Compression braking in a gas rig uses the engine to slow the vehicle, not very effective in a diesel UNLESS the diesel has some type of gate to create vacuum or backpressure. 12v cummins.....no luck, 7.3 up fords....luck.
There is also a retarding feature in some auto transmissions that use the converter to eat up load. Early transmissions had troubles trying to redirect load through different bands....fords would chew reverse band by down shifting manually. Allison retarder was/is awesome.
My '08 Dodge 6.7 Cummins has an exhaust brake, not compression. It's a little less effective but a lot quieter. Mechanics say to use it all the time, not just on hills. They say that during the braking cycle, it will keep the crud blown off the turbo and make the turbo last longer.
That's the "gate" to produce backpressure. The only down side is it can float valves in extreme situations. Factory setups have enough safeties in them to make it nothing to worry about.
Originally Posted by BrentD
I would not buy something that runs on any kind of primer given the possibility of primer shortages and even regulations. In fact, why not buy a flintlock? Really. Rocks aren't going away anytime soon.
You don't say what year your pickup is, but almost everything made in the last 8 years or more, the engine/transmission computer interface senses several inputs as you start downgrade, you manually drop down one notch on the selector, or press a button on the dash, apply the brake at the speed you want to maintain for about 2 seconds, and the release brake pedal and inasmuch as the engine and transmission can, it will try to maintain the speed you selected. Think of it as setting a downhill cruise control. This of course doesn't work well with a 14,000 pound backhoe on a 6% grade. Owners manuals are so dumbed down that they don't explain this well, Toyota, Dodge and GM all have it, I don't know about Ford or Nissan.
Well this is a fine pickle we're in, should'a listened to Joe McCarthy and George Orwell I guess.
I was surprised by the 05 Durango w/ 5.7 and five speed auto when we got it. It was the first vehicle that I had ever seen which, with cruise control on, down shifted automatically to reduce speed on downhill grades.
To the OP's question. Yes it is absolutely advisable to downshift the automatic transmission in down grades. It will not hurt the transmission, and on a long down grade will prevent brake failure.
Sometimes it is necessary to tap the gas pedal a little bit and raise engine RPM before the trans will actually shift into the lower selected gear. At least this is true on the older vehicles I have driven.
People who choose to brew up their own storms bitch loudest about the rain.
Been driving going on 50 years, all of my vehicles were manual transmission until last year when I bought a Nissan Frontier pickup. Engine braking (going down a hill in a lower gear instead of riding the brakes) ain’t much of an issue in mostly flat Texas.
Last month I was driving around Pennsylvania, Upstate NY and Vermont, lots of steep grades. Way back in the 60’s my English grandpa taught me you drive down a hill in the same gear you’d drive up it.
Engine braking with an automatic transmission, good or bad?
Been driving going on 50 years, all of my vehicles were manual transmission until last year when I bought a Nissan Frontier pickup. Engine braking (going down a hill in a lower gear instead of riding the brakes) ain’t much of an issue in mostly flat Texas.
Last month I was driving around Pennsylvania, Upstate NY and Vermont, lots of steep grades. Way back in the 60’s my English grandpa taught me you drive down a hill in the same gear you’d drive up it.
Engine braking with an automatic transmission, good or bad?
............I suggest you consult with a trans specialist cuz opinions will vary one way or another here on this one.... I have a 2015 Ram Hemi 2WD truck with the 8HP70 8 speed auto trans. Although I do not downshift all of the time, I have not had any issues downshifting on downgrades or on off ramps. In fact, there are two buttons on the steering wheel; one for upshifting and one for downshifting. Never have had a wrench turned on my transmission @136K plus miles. Only fluid and filter changes....Shifts just as good and as crisp now as when I bought it new.....Of course the trans fluid that I use, namely the Amsoil Signature Series full synthetic beginning at 55K miles and changed again at 125K miles, may have something to do with my trans still shifting as good now as when that truck was brand new........
What would you rather replace - brake pads or transmission parts?
Exactly!
Towing a load down 6 or 10 miles of six percent grade, and you refuse to abuse the transmission by downshifting will guarantee you never have to repair the tranny....or the brakes.
People who choose to brew up their own storms bitch loudest about the rain.
