Help shifting a 6spd Eaton Fuller?

I had a 5 speed mack a very long time ago and I do not recall exactly where I shifted at. The range is from 600 idle all the way to 2300. It's not a very fast truck. Engine starts to wake up about 1300. Begins to pull ### off at about 2000.

All heavy truck engines have a torque RPM below which it will refuse to pull anymore and begin to lug, buck, bounce or fight you. Or even stall. That is your bottom number. Find a big hill, hit it in one gear stay in it until that nose starts hopping. There is your torque RPM.

You can literally hear by ear it's song. If it's coughing a fit it's not working well in too high a gear, downshift one GENTLY and Smoothly. If you get it in there, music should be the result. If you push it too much you will feel as if you about to lose your drives or your turbo screech icepick in your ears. Time to shift up.

There is also a high horse power RPM. today's trucks are engineered to run about 400 or 500 RPM apart between the two RPM's for either wind it out shifting or progressive shifting (Which is beyond the scope of this post)

Your rig should be at least 500 RPM higher than that point at which she bounced or bucked on you at or under Torque RPM. You can probably find the engine stamp on the block, google it by make and model and discover it's operating chart which all engines have. Which is a curve expressed between two RPM's for shifting.

 

Why does everyone think there is a magic speed to gear correlation without knowing rear ratio and tire size. Even then we have to plug it in to get close.


Here's a hint start at your best guess. Dont push hard on the stick, if it doesn't fall in gently bring up the rpm if by 1500 it doesn't fall in go down one hole repeat.


Is this in a M2 business class by chance?

 

I haven't seen a class 8 with a 6+1 in it, seen a bunch of fl-50/60s and m2s with them

 

Freightliner M2 106 is what I drive and its easy - peasy.
Someone once said they stopped reading a post I put up after I said something about 2500 RPM.
The 3126 Cat sings like a bird at that, 2000 is good for a steady 70 MPH all day.
I have 19.5 tires on and usually start out in 2nd, run it up to 1500, shift, 1500 again, shift, etc.
Coordinate depressing the clutch so it's about a half second before you move the shifter.
Same with on the way down, its a slow progression - w/clutch all the way in, select next lower,
let it out easy, and on and on. Don't like to over-rev either going up or down,
as there is no load, and it truly is just over-revving the engine.
Get on a side road with no one behind you and just do it.

 

I have a 6 speed international 4300 flat bed tow truck and it’s fully synchronized.
No double clutch or rpm matching required.

 

I actually do the whole clutch release thing first, and then put it - to it.
I buy the parts, and I do the labor, (clutch,) - and don't slip it unless absolutely necessary.

The 1500 RPM thing is just a reference of what it sounds right to shift at - for me, on this unit.
I follow thru with pedal to the metal each time- smoothly, with no lurching or stalling; it must work?
Got the comment once from someone that I had a "Ham - Fisted driving technique."
I'm not racing anyone, but I don't go slow either. Shifting to me is to get me up to warp speed.
I'm not delicate doing it, but I don't grind gears either. Hesitate with slight pressure and it drops in.

 

My 98 4900 came with a 6+1 a DT530 and 5.38 rears. I floated them just like bout anything else