Question about auto transmissions

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Old 03-27-2009, 01:00 AM
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Default Question about auto transmissions

Today, as I was gearing down at the top of a hill before heading downhill, on my 18-speed, with a weight of about 130,000 lbs, it suddenly struck me that how would i do this if my truck had an automatic transmission. Would I be slowing the truck pulling such a load, by using just the brakes & the jakes ?
 
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Old 03-27-2009, 01:11 AM
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Originally Posted by Graymist
Today, as I was gearing down at the top of a hill before heading downhill, on my 18-speed, with a weight of about 130,000 lbs, it suddenly struck me that how would i do this if my truck had an automatic transmission. Would I be slowing the truck pulling such a load, by using just the brakes & the jakes ?

It's been a lot of years since I used a truck with an automatic tranny...but for my money, with the weight you are talking about...at the top of the hill you would switch the tranny from auto over to manuel, preselect a gear low enough to hold the weight, yet high enough for you to maintain a decent downhill speed, use the jakes as needed, and the brakes sparingly...especially on a long grade. Switch the tranny back over to auto after regaining top gear.

On shorter grades, you would use higher gears.

Just my opinion.
 
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Old 03-27-2009, 01:29 AM
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X2 Stan.
 
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Old 03-30-2009, 01:05 AM
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Originally Posted by Graymist
Today, as I was gearing down at the top of a hill before heading downhill, on my 18-speed, with a weight of about 130,000 lbs, it suddenly struck me that how would i do this if my truck had an automatic transmission. Would I be slowing the truck pulling such a load, by using just the brakes & the jakes ?
we have 8 axles and permits for 105500
our company went to auto shift and the trucks are equipped with the telma electric brake on the driveshaft. we can downshift manually but with that telma brake we get down the hill lots faster than we used to with out heating up the brakes
 
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Old 03-30-2009, 03:52 AM
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Stan is correct about switching to manual before heading down the hill.
 
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Old 03-30-2009, 04:45 AM
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Originally Posted by homer
we have 8 axles and permits for 105500
our company went to auto shift and the trucks are equipped with the telma electric brake on the driveshaft. we can downshift manually but with that telma brake we get down the hill lots faster than we used to with out heating up the brakes
What is that? Neve heard of it....but then...have not driven a truck with an automatic...even that one you have....since 1986.
 
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Old 03-31-2009, 12:10 AM
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Stan, I googled Telma Electric Brake. Interesting reading. It's like a housing that goes around the driveline. I think you could use it on any truck, Not just one with an automatic transmission.
 
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