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Topic: Can We Have A Manual Down-Shifting Discussion? (Read 1553 times) previous topic - next topic

Re: Can We Have A Manual Down-Shifting Discussion?

Reply #40 –
Different engines have different RPM limits. Usually, the larger the displacement, the lower the maximum RPM.

Pierce

Re: Can We Have A Manual Down-Shifting Discussion?

Reply #41 –
I can remember testing the Allison in the early 90s.    Driving a Ford 700 with a manual trans my left knee was starting to have problems ( clutch ) so I mentioned to the supervisor that the next new truck needed to be an automatic.    He was very hesitant because the company didn't think an auto would hold up.  They ordered one anyway and I never gave that transmission any mercy,, couldn't cause that route ended at 10:00 pm and I needed to get-er-done.    Stick it drive and smash the throttle.        That truck or transmission never gave me a bit of grief.  It held up to anything I ask of it.....  but that company also had excellent service policies.
      And the truck was propane.

 

Re: Can We Have A Manual Down-Shifting Discussion?

Reply #42 –
Quote from: Chuck & Jeannie –
I have been led to believe that the Allison brain will trigger a upshift to prevent engine overspeed, regardless of what gear is manually selected.  Have you ever observed this behavior from your transmission?  Just looking for comments from more experienced owners, like yourself.

I have not personally tested this assertion.  I don't ever let our C8.3 exceed 2450 (governor break rpm) - "Better safe than sorry".


I haven't checked in years, but believe my isl400 is ok to 2700-3000rpm in overrun (foot off the gas pedal). Somewhere in that range it will automatically upshift. I've never tested it. But the alarm sounds at 2500rpm. When that happens I hit the service brake and also retarder if cool enough.

Re: Can We Have A Manual Down-Shifting Discussion?

Reply #43 –
For another 2003 ISL 400. Serial number: 46210160:

Peak Torque 1200 lb-ft @1300RPM.
Peak HP 2100.
Governed RPM 2330.
Overspeed 2600.

Re: Can We Have A Manual Down-Shifting Discussion?

Reply #44 –
Quote from: Roland Begin –
To WildBil
Yes when over revving the transmission will upshift. Corrected my post.
Roland
I know you knew it, must have been the spell check. :))  ^.^d
I am looking forward to getting on the road to try my new setup. I have a real engine brake now. on my ISM.
Bill

Re: Can We Have A Manual Down-Shifting Discussion?

Reply #45 –
Owned 3 cars, van and pickup with no synchro in first gear. All were three on a tree. 

Re: Can We Have A Manual Down-Shifting Discussion?

Reply #46 –
Quote from: Realmccoy –
Owned 3 cars, van and pickup with no synchro in first gear. All were three on a tree. 
Are you sure it was no syncro in first?  I drove an old '50s two ton truck with syncro only in first, you had to "double clutch" between all the other gears. 

Re: Can We Have A Manual Down-Shifting Discussion?

Reply #47 –
Quote from: Pierce & Gaylie Stewart –
Does anyone here remember double clutching?

Pierce

Rode shotgun with my Dad as a toddler watching him double clutch his International flatbed. He had a brick and stone business in Western New York, I couldn't wait until my legs were long enough to reach the pedals.  Set me up for a lifelong yearning to push on a go pedal and see the countryside...
 

Re: Can We Have A Manual Down-Shifting Discussion?

Reply #48 –
These hills in Vermont have been giving my coach a workout for sure. I have mostly left it up to Allison to manage the gearing, but will try more manual shifting options heading up to Maine and see how that works out. I only use economy when its pretty flat. The retarder is getting a good workout on these roads.