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Why shift to 2 or 1 going uphill?

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Bale

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Discussion starter · #1 ·
Just curious: The owner's manual says you should shift to 2 or 1 when climbing steep inclines.
I see the point of that going downhill, to get better engine braking, but why do it going uphill? Won't the transmission select the appropriate gear automatically?

(Guess I have a 42RE transmission and 249 TC).
 
#4 ·
That only applies to a manual transmission, and you have an automatic. Someone please correct me if I'm wrong though.
 
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#5 ·
Bale said:
Just curious: The owner's manual says you should shift to 2 or 1 when climbing steep inclines.
I see the point of that going downhill, to get better engine braking, but why do it going uphill? Won't the transmission select the appropriate gear automatically?

(Guess I have a 42RE transmission and 249 TC).
Click to expand...
So it will stay locked in that gear & not try to upshift.
 
#7 ·
Same reason when you're towing a trailer and usually have the OD off. More power, and for going up hill more traction. If you take a hill in OD that is say a 10% grade and you're going 35 mph...you're going to be going nowhere fast. You won't have the power to carry the vehicle up the hill. Same reason you use 1st or 2nd when hill climbing off road, you get more traction and more power to the ground to carry you up the hill...Somebody can explain it better than I did..but I gave you a general idea.
 
#8 ·
Most of the answers are far are pretty correct. The biggest reason is transmission heat because the torque converter slips more when upshifting below 2250rpm. Above 2k and you reach the natural stall speed generating less heat on a tough section of terrain.

This is for things like rocky mountain grades and off road hill climbs. Not to be used over 25mph this way.
 
#9 ·
When I used to go up 7% grade hills I had to turn O/D off to make the 5.2L V8 get up the hill... I did it to save my transmission from blowing up by switching back and forth from 3rd to 4th, obviously that didn't work.
 
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#10 ·
When the engine RPMs are up you are delivering max transmission fluid pressure to the clutches, and max flow thru the cooler. And as noted you're also above the converter stall speed which reduces converter slip which in turn reduces fluid heat.

It's also a control issue. The last thing you want is an unintended upshift because you backpedaled for a big rock, etc. When it upshifts you'll apply more throttle, which creates a downshift, which will create lurching and wheelspin. Not the hot ticket for a vehicle that's in a precarious situation. Precarious situation equals smooth application of controlled power.
 
Discussion starter · #14 ·
Thanks, think I get it now:

- Easier on the tranny (less chance of overheating), as long as you stay within reasonable (not too low) RPMs

- Prevents gearshifts that could induce wheelspin and loss of traction

Makes sense, I guess! :thumbsup:
 
#15 ·
Bale said:
Thanks, think I get it now:

- Easier on the tranny (less chance of overheating), as long as you stay within reasonable (not too low) RPMs

- Prevents gearshifts that could induce wheelspin and loss of traction

Makes sense, I guess! :thumbsup:
Click to expand...
Bale, thank for bringing this question up here because it makes me think .

I know far more about old muscle cars, old foreign car and old motorcycles than I know 4x4's .

And my 2 cents, may very well, mean nothing here .

I am here to learn and help some if I can .

Phit
 
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