TXBobcat
Fulltime
Have a question for those with the Allison transmission or a smilar one like the one on my Ford.
I was just reading the new edition of the Escapees Magazine. The article Mountain Driving, pages 24, 25 & 26. On Page 26 third column 3rd paragraph. They are discussing driving a Workhorse W22 gas chassis MH using the Grade-Brake feature of the Allison transmission. I didn't know what it was called. Huh... Learned something new. They wrote "Mike allowed the vehicle to run against engine compression with the engine speed varying between 4,000 rpm to 5,200 rpm depending on the grade. Each time we hit 5,200 rpm the transmission would force a shift to 3rd in order to protect the engine. Each time this happened Mike applied the brake for a few seconds to scrub off speed and this allowed the transmission to down shift to second gear again, allowing maximum engine breaking in the safe speed range".
Now one of the things they mentioned earlier is that they elected not to use the Grade Brake but preferred to manually shift down using the column shift.
Has anyone not used the Grade Brake and had it shift up? I have always used the Grade Brake. I thought that was what is was built to do.
When going down a grade that was about 8% I used the Grade Brake and hit the brakes only when needed to keep it down to a lower RPM and a speed that was safe.
I would enjoy to read your comments.
BC
I was just reading the new edition of the Escapees Magazine. The article Mountain Driving, pages 24, 25 & 26. On Page 26 third column 3rd paragraph. They are discussing driving a Workhorse W22 gas chassis MH using the Grade-Brake feature of the Allison transmission. I didn't know what it was called. Huh... Learned something new. They wrote "Mike allowed the vehicle to run against engine compression with the engine speed varying between 4,000 rpm to 5,200 rpm depending on the grade. Each time we hit 5,200 rpm the transmission would force a shift to 3rd in order to protect the engine. Each time this happened Mike applied the brake for a few seconds to scrub off speed and this allowed the transmission to down shift to second gear again, allowing maximum engine breaking in the safe speed range".
Now one of the things they mentioned earlier is that they elected not to use the Grade Brake but preferred to manually shift down using the column shift.
Has anyone not used the Grade Brake and had it shift up? I have always used the Grade Brake. I thought that was what is was built to do.
When going down a grade that was about 8% I used the Grade Brake and hit the brakes only when needed to keep it down to a lower RPM and a speed that was safe.
I would enjoy to read your comments.
BC