Downshifting
 

im looking to get my CDLs and start a new career...ive signed up with Schneider to go to Charlotte hopefully 3/15....im trying to get a headstart with driving here at work... i work in a warehouse and run the docks but occasionally i get to drive a switcher truck and since ive gotten my learner's permit ive tried driving one of the mack's that we use to go between plants that are a couple miles apart....i dont any issues up shifting but its the downshifting that im having a diffucult time doing.. are there any tricks to it ??? if anyone could give any suggestions I would definately appreiciate it.. Thanks!!!!

Takes practice .

Match the RPM to speed .

Kick up the RPM about 200 to 400 and then shift .
You just have to learn to watch the tech , until it becomes natural .

It actually works much better when you watch the tach. 8)

I keep tryin... but its not working out very well...guess im not holding my tongue right ....maybe tomorrow night I can ride with someone for a few hours and watch them and see how they do it.....

You're not rapping out on the next gear up are you?

i dont believe so... couple of the full-time switchers that use the mack's regularly say that the ones we have are difficult to learn on.... i believe them :lol:

Re: Downshifting
 

I hope I can say what I am trying to explain, example.. if you go from 6 to 7 at 35 mph and 1900 rpm ( just made up numbers) then when you downshift from 7 to 6 you would do it at the same speed and rpm. so you would get down to 35 mph, push the clutch in, rev it to 1900 and shift into 6. I hope you can figure out what I'm trying to say, it's hard to figure out how to say it.

If it's an older Mack with a 5 or 6 speed transmission, then there is about 900 RPM's between gears.

If you're trying to downshift one of those by raising the RPM's by 400 RPM it ain't gonna work.

the old 5 speed maxidynes were something else, the first one I drove the boss said wind it up, kick it onto neutral, count to 100 then hit the next gear, he wasnt far off :D :D

:oops: Beer and typing don't mix !

All I drive is 10 speeds so my style might not work for what your driving but this is what I do and its good info. I watch the tach and the speedo.

For down shifting here is a speed chart

9th - 45mph
8th - 35mph
7th - 25mph
6th - 15mph
5th - 10 mph
4th - below 10mph, only need a small shot of fuel to get her to slide in

I remember these if I miss a gear down shifting or up shifting, lets say I had to stop really quick for what ever reason, car pulls in front or stops all of a sudden. To get going again I look at the speedo, move it in front of the gear I know it will go in, give it some fuel and she will slide in.

Stopping for red lights and general stopping I use the tach, If I skip down shift two gears, from 10th to 8th I let the rpm drop to about 900, give it fuel to around 1500 ( that depends on your truck) and she will go into 8th, or one gear I let it go to 1100-1200 rpm, shoot the fuel to 1500 and she will go to 9th for example.