ATs and mountain(downhill)

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pandus13

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Hi BITOGers,

I was coming back from FL to Chi and passed trough TN mountains (anybody from the Rockies, please don't make fun of me, i live in a flat plane).

Catch some traffic going up (smelled some AT, not burn smell), then the downhill started.

I intermittently pumped the brakes, and kept the right lane (out of the way of the 2FT bumper followers).

How do you use your AT in mountains (UP and DOWN) safely (no boiling/burning liquids)?

Thank you

P.S. i ask this because i remember a story where someone was behind a truck and he never light up the brakes because he was using the correct gears Downhill....
 
I don't really do anything different. All of my cars except the Trans Am (6 speed Manual) have large coolers.

The truck when towing, I let it do its own thing. When towing 7500lbs and heading down any of the larger passes here out west. I usually just lift off the gas. The trailer does not usually push the truck. I need very limited brake use with my set up. 4L85E/4.10 gears I have never seen the tranny temp go over 210 even when towing heavy in the heat of the summer.

The Caprice has a huge aux tranny cooler. No worries there.

Now I can tell you about burning up power steering fluid in the truck with hydro boost brakes...
smile.gif
 
I lock it out of OD, never had a problem doing that, and use the brake when needed going downhill. If things got hairy second or third gear briefly [depending on the vehicle] and the brakes, going downhill.
 
All our 3500 service vans have fancy grade logic in them. If enabled the trans does a ton of downshifting, but we live in the flat land of Florida.
 
Get good brakes so you don't have to worry about brake fade? Or you can just drop the car down a gear at the speed you are moving downhill and let the engine do the braking for the most part. At 40 MPH drop from 4 into 3rd and the engine should do at least enough braking to reduce the use of brakes to a point where even cheap brakes won't fade.
 
For your cars I don't think you have to do anything special even in the rockies, unless you have the 5 loaded to the gills. Then just pick a lower gear for going downhill. Locking in 3rd is probably all you'd need on any major hwy's, going up or down at 50-55mph if you want to be super easy on the car.
 
I make that same trip once or twice a year, usually with our 2004 Sienna 2WD van. (This is on the Interstate). On the way up, I just leave in drive. On the way down, I downshift a gear or two and don't use much braking at all, control speed with the throttle.
 
Originally Posted By: IndyIan
... unless you have the 5 loaded to the gills.

YEP,
2 adults, 2 kids, vacation luggage (3rd row down) ( yes i did carried sand and shells)

(I think the AT smell was from slightly overfilling at the last drain-and-fill.)
 
Going uphill I try to keep the torque converter locked as much as possible, that keeps it a bit cooler. There's times where I'll force the Cherokee into 2nd gear when climbing hills so it will climb the hill at 3500/4000 RPM in 2nd gear with the torque converter locked opposed to the same RPM with it unlocked in 3rd gear.

Going down, there's not much you can do unless you have a newer, smarter auto that will downshift and keep the torque converter locked. I'm kinda out of luck with the cherokee there. I did manage to smoke the brakes in PA pulling into a rest area to check on the trailer tires once.
 
Engine braking is stronger in lower gears. If you pick the correct gear for the conditions you will not need to touch the brakes except in an emergency.

Engine braking eliminates brake fade, ensuring the brakes will bite as intended if/when you need to use them.
 
Originally Posted By: Miller88
Going uphill I try to keep the torque converter locked as much as possible, that keeps it a bit cooler. There's times where I'll force the Cherokee into 2nd gear when climbing hills so it will climb the hill at 3500/4000 RPM in 2nd gear with the torque converter locked opposed to the same RPM with it unlocked in 3rd gear.
Yikes, those big tires are really eating up your power.

The only time I've ever downshifted my Jeep is when pulling my 2,000 pound trailer, and that's because everyone says to tow in 3rd to keep the tranny cool. It has no problem pulling.

I've taken it up some steep mountains, 75+ mph is no issue.
 
I put the F150 in manual mode and select the right gear for the hill. Coming down Pike's Peak it was 1st gear and 4000 rpm for half the trip.
 
You don't really need engine braking for descending the Smoky Mtns, IMO. The grades are not extremely long or steep.
 
More modern vehicles with any kind of grade control logic make it so you don't have to think about it much.

Previous vehicles, I use the gearing to keep off the brakes. Most of the time, locking out OD will do enough, otherwise some manual downshifting happens.

Have heard from others in my family "how did you not touch your brakes coming down that mountain pass" more than once... Use the gearing just like a big rig. Means my brakes are fully available if and when I need them...
 
Originally Posted By: Olas
Engine braking is stronger in lower gears. If you pick the correct gear for the conditions you will not need to touch the brakes except in an emergency.

Engine braking eliminates brake fade, ensuring the brakes will bite as intended if/when you need to use them.


The new automatics have plenty of gears and are easy to shift. I shift mine around town and in the mountains. Cuts way down on brake wear and adds to the fun of driving.
 
Originally Posted By: Nick1994
Originally Posted By: Miller88
Going uphill I try to keep the torque converter locked as much as possible, that keeps it a bit cooler. There's times where I'll force the Cherokee into 2nd gear when climbing hills so it will climb the hill at 3500/4000 RPM in 2nd gear with the torque converter locked opposed to the same RPM with it unlocked in 3rd gear.
Yikes, those big tires are really eating up your power.

The only time I've ever downshifted my Jeep is when pulling my 2,000 pound trailer, and that's because everyone says to tow in 3rd to keep the tranny cool. It has no problem pulling.

I've taken it up some steep mountains, 75+ mph is no issue.


They definitely kill the power. My camping and off roading trip to PA was an interesting drive towing the loaded up camper. On some of the bigger hills 40 was about all it could manage with my foot firmly planted on the floor. But there's a reason I prefer to tow the camper with my Focus haha.
 
It's not something we've worried about in 20 or 30 years. Old transmissions (and brakes) were an issue for vehicles in mountains, but anything reasonably modern is built to handled grades unless you're grossly overloaded.
 
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