Stuck driving 1 OLD truck, help, 66Mack DM800

Handed down to me was a 1966 Mack DM800.....I am 32 and run a asphalt paving company, the truck runs about 3 days a week and hauls 20 ton..

Since its almost impossible to make money these days, Im stuck with this bad boy And im the only 1 willing or can drive this monster..Its got a 5-4 tranny, 2 sticks, Mack engine....

My problem with the truck is its very low power and gear grinding....Almost every gear change there is grinding...What can I do or tell a mechanic to help with the grinding??...Lube, Grease fittings???

Also the gas pedal is a horror,,,I feel I am pedal to the medal before I get any power going, the slightest incline and the truck feels it...Its almost impossible climbing a hill with speed, its pop it in its lowest gear and creep up that hill. So are there any adjustments I can make to get that gas pedal tighter so i get more power with just a little push on the pedal...

 

I will definitely check the oil in the tranny, will I get a better reading taking out that bolt or might there be a dip stick for tranny fluid..

I just had the gas pedal looked at and the guy told me a small pin broke off, he replaced it, but it feels the same to me..I wanted a tighter pedal so when I press the gas right away I get some power..I am literally standing on the pedal down to the floor the entire drive...

And she is definitely worn out..Its a freaking 1966, Truck surprises me every day...

trying to get some pics up...

 

Maybe 50 mph tops unloaded....As for the gear grinding, I have tried a number of things. i have tried changing gears at high and low rpm's and even tried it without using the clutch....Clutch really is no difference, grinds the same with or without the clutch...

Truck seems like it should be part of a big yard. somewhere where she just stays in a low gear and off the road....

But I think im just stuck....most are right, these are just how they ran back in the day....

Wish I got payed by the hour...Cause it takes me a very long time to get anywhere...Only reason why I ask about the truck, is because it looks real bad on the road when Im pedal to the medal and not going anywhere....

 

Oh Man what a FREAKING DAY....After putting down 30 ton of asphalt, Im on my way back in and when stopped at a red light, by gas pedal completely goes...had nothing...

Had to pull it to a side road with my little ford and that was no easy task,,,this is 1 heavy dump truck, not one piece of plastic or fiberglass anywhere...

Mechanic comes and these L shaped links must have broke, he replace 2 and I was set, but when testing the gas pedal he noticed when Im pedal to the ground Im only at 75% throttle...

Stumped as everyone else it as why he cant get the pedal tighter...He says the rod that comes up from the floor of the truck that holds the gas pedal up is bent...If it was straight he thinks it would not hit the floor right away....But it was something he was not interested in touching...I guess if you Try and bend it straight it might just break...And it seems like getting into fix anything is tight and very annoying to work on.