When is 600HP not enough.

[LongRanger]

At the Freightliner class Mike said that you need to be proactive and downshift early to keep the rpm’s up.

[8TiresRollin]

Originally Posted by PanJH

You need to watch the water and tranny temps-- lugging at too low RPM will raise them and could be the start of trouble. Knock it down an gear or 2 and get it in the sweet spot.

And will drive your EGT up to the sky high limit. Bad for turbo.

[Desertboyz]

I used to take the 154 as a short cut when I went to Cal Poly SLO about 100 years ago. I passed all the old farts with their rigs but usually got stuck behind the one old goat who had to win at the top right before it turned to one lane. And then he went 45 until it opened up again.

[Stuart W]

The 154 has always been my choice, motorcycle, car and RV, saves about 20 minutes going north. Technically I think it’s restricted to 40 feet and under.

[Deucenut]

Originally Posted by BBelanger

I plead guilty to not manually operating my transmission. I just keep the pedal to the metal or the cruise control on, and I pass tractor trailers going up hills. I figure everything must be working alright. Doesn’t the automatic transmission have all this stuff programmed properly?

Driving like this in hilly or mountain terrain will cause your transmission to eventually overheat, not to mention your rear end. I would suggest if you had a Pyrometer gauge, your exhaust gas temps would be way up in the red and you'll be going through fuel like crazy!! Yes, the transmission and the computer are programmed to downshift etc, but there is such a thing as being easy on the equipment IMO.

If you trade your coach in every 4-5 years (like a lot of people on this site seem to do) then by all means, drive it hard! lol If you plan to keep it for the long haul, then going easy, backing off a little and downshifting is your best bet for the equipment.

[Rotten-Red]

Originally Posted by Deucenut

Driving like this in hilly or mountain terrain will cause your transmission to eventually overheat, not to mention your rear end. I would suggest if you had a Pyrometer gauge, your exhaust gas temps would be way up in the red and you'll be going through fuel like crazy!! Yes, the transmission and the computer are programmed to downshift etc, but there is such a thing as being easy on the equipment IMO.

If you trade your coach in every 4-5 years (like a lot of people on this site seem to do) then by all means, drive it hard! lol If you plan to keep it for the long haul, then going easy, backing off a little and downshifting is your best bet for the equipment.

How is the rear end temperature going to be affected by engine RPM or what gear the transmission is running in? The drive shaft will be turning the same speed regardless what gear your in or the RPM.

[BobKatMsu]

Driving through Montana today and showing DW, who was driving how to down shift manually. She loved blowing by the 18 wheelers.

[TonyMac]

Horsepower is not the issue. The issue is this guy does not know how to drive. Nice to know he's out there -- somewhere -- with 40,000 pounds of mayhem.

[Deucenut]

Originally Posted by Rotten-Red

How is the rear end temperature going to be affected by engine RPM or what gear the transmission is running in? The drive shaft will be turning the same speed regardless what gear your in or the RPM.

Lots of torque can heat up a rear end.

[Rotten-Red]

Originally Posted by TonyMac

Horsepower is not the issue. The issue is this guy does not know how to drive. Nice to know he's out there -- somewhere -- with 40,000 pounds of mayhem.

Who you talking about?

[BigDogSolo]

Allison actually recommends being proactive by downshifting going up (and down) grades versus letting the automatic "take over".

[TonyMac]

Originally Posted by Rotten-Red

Who you talking about?

The boy with a 600hp engine but not enough skills to know how and when to downshift. I think I had that figured out at age 16.

[TonyMac]

Originally Posted by BigDogSolo

Allison actually recommends being proactive by downshifting going up (and down) grades versus letting the automatic "take over".

I've never seen that. Can you tell me where you found this and what trannys it applies to? My Allison is pretty good at selecting the proper gear, so I let her do it. Sometimes she up shifts, only to lose speed and have to downshift. I'll take over because she can't see out the front window and doesn't know what's coming. I'll down shift manually, and pick a speed that is comfortable for Allison and her Cat, till we clear the grade. But usually, she does a pretty good job by herself.

[Deucenut]

Originally Posted by TonyMac

I've never seen that. Can you tell me where you found this and what trannys it applies to? My Allison is pretty good at selecting the proper gear, so I let her do it. Sometimes she up shifts, only to lose speed and have to downshift. I'll take over because she can't see out the front window and doesn't know what's coming. I'll down shift manually, and pick a speed that is comfortable for Allison and her Cat, till we clear the grade. But usually, she does a pretty good job by herself.

My Cummins manual specifically says to up/downshift to maintain optimal rpms