double clutching

[609albert]

just got my L 54 MACK back on the road and not used to the shifting double clutching ,start out in 2nd gear and have trouble sometimes getting into 3rd, have to stop and start again,sometimes catch it just right, also downshifting from 4th to 3rd, I know you have to catch the engine speed just right.

would a tachometer help me or any other hints that would help shifting?

[Rob]

just got my L 54 MACK back on the road and not used to the shifting double clutching ,start out in 2nd gear and have trouble sometimes getting into 3rd, have to stop and start again,sometimes catch it just right, also downshifting from 4th to 3rd, I know you have to catch the engine speed just right. would a tachometer help me or any other hints that would help shifting?

A tachometer is a good visual aid but once you relate the shifting sequence to the engine sounds and vibrations, it will be 2nd nature to shift the truck. Everything has a learning curve. Practice, Practice, Practice, is the only way to become a master.

Rob

[fxfymn]

With my Mack I have found that I need to pause quite long in neutral with the clutch out when upshifting in order to shift smoothly. When downshifting I found that I need to wait for the road speed to fall back to about the top end of the next gears goes to before shifting. I have to raise the RPMs quite high in neutral with the clutch out as well.

It is odd, but most Mack fire apparatus from this era does not have a tach on the dash. Mine has a splitter on the pump panel tach drive cable, but a tach was never installed on the dash. I miss it, since I was so used to driving something with a dash tach to help find the shift points.

[Olivetroad]

I find it is a lot easier for me when driving a truck I am not used to, especially an older one like that, to drive it loaded or pulling something to get the shifting down. It just seems to make things happen smoooother. All engines and transmissions are different, and like Robbie says, it just takes time driving the truck between the paint stripes to get it down.

That info and a quarter will NOT buy you a cup of coffee.

[Greg Rider]

Watch the first few seconds of this video and LISTEN to how far the revs drop. This is a second gear start to third. Later after I make the turn listen again as I upshift.

[jaysm35a2]

When empty I upshift at just about 1200 RPM , he's right its alot easier to shift a Mack tranny with a load behind it.

[Rob]

Watch the first few seconds of this video and LISTEN to how far the revs drop. This is a second gear start to third. Later after I make the turn listen again as I upshift.

That sounds like a TR-67 Mack transmission. They work much better with a duplex, or triplex Brownie behind them.

Rob

[Greg Rider]

The tranny is a Spicer 5A-330 or SA-330,, I don't remember right now. I know that the difference is the zero on the end makes it an overdrive tranny. I don't recall what the mack part number designation is for it.

Shift pattern is;

1 2 5

R 3 4

First is low and fifth is over, I normally start in second.

[Rob]

The tranny is a Spicer 5A-330 or SA-330,, I don't remember right now. I know that the difference is the zero on the end makes it an overdrive tranny. I don't recall what the mack part number designation is for it.

Shift pattern is;

1 2 5

R 3 4

First is low and fifth is over, I normally start in second.

It certainly sounds to have close to the same rpm drop between gears as my A40 does if the auxilary trans is not shifted.

I have a Fuller in my R190 IH that first is over to the right and up, 2nd through 5th are conventional in pattern, and reverse is to the left and up. It works best if you split each shift with the two speed axle.

Rob

[Greg Rider]

Notice later that the drop from 4th to 5th isn't as steep as the others.

[Rob]

Notice later that the drop from 4th to 5th isn't as steep as the others.

That must have been commonplace among the manufacturers. None of my trucks do you split in the higher speeds. You go from 4th high, to 5th high without any split.

Rob