Hey everyone! The other day I hauled 2 loads of gravel weighing 7 tons each. On my way home, the transmission jumped out of 4th gear but the shifter lever stayed in place. I think the input shaft is broken because you can put the truck in any gear, let out on the clutch, and nothing happens at all. It made a horrible rock crushing kind of noise. The transmission is a New Process 542 model. Do any of you have any idea of a parts source for these older transmissions??? If not, can any of you think of a popular tranny swap?? My truck is a 1979 F-700 with a 370 engine that runs on gasoline. The PTO runs off of the transmission as well. I really do not want to scrap my old dump truck, but I don't want to dump thousands of dollars into it either. Please help!!!

 

ware are you located? might have a junkyard you can try

 

 

oh that's about 6 hrs away. if you cant find one closer let me know I will take a look in the 2 yards I think would have one. (neither of them have a phone # that I know of) if you are able to rebuild the trans I could even take it apart and just ship what parts you need.I know I have seen a couple of the big dent and bump side's out there just don't know what trans they have.
do you know if the np 542 out of a chevy or maybe a school bus is the same?

 

Thank you very much! I am not certain about using one from a chevy or dodge. I think the input shaft lengths may have been different dependent of the application. I am going to try to get the tranny out on Wednesday and hopefully by then I will have some sort of idea of what all parts will need to be replaced. Thank you again for your willingness to help out with my situation.

 

Moved to the correct forum. Hopefully, you will get more help in here, if needed.

 

Highly doubtful about the input shaft, more like clutch disk rivits went south, seen it
many times. My first test would be engine off trans in neutral engage PTO and try
and turn the PTO shaft and listen..

 

Thank you all for the replies! I just got the transmission out yesterday and to my surprise there is no obvious damage to any of the gears and in fact they all look like new with minor wear.....There is a small amount of play in the input shaft but nothing extreme. I turned the input shaft by hand and the output shaft will turn also. Now please remember that I am NOT a mechanic, transmission specialist, or professional machinist so it is quite possible that I am overlooking something. However, in my honest opinion I think that the transmission might be ok.


BIGJOB, you seem to think that maybe the rivits on the disc are bad. I forgot to mention that when I bought this truck last year it would not downshift properly either. If the truck was going over 30 miles per hour, and I would try to downshift to slow it down then it would act as if it went into neutral and make that gravel crunching noise just like it did last week when it finally died. I am so hoping that you are right because it would be much easier on my wallet if I have to replace the clutch than the tranny. The previous owner rebuilt the clutch "a while back", but the Low/High range has never worked since I owned the truck. It was stuck in high range and I have no idea how long it has been that way.


I will keep you all posted on this as I proceed, but as of right now I am thinking the transmission may be ok. It will be next week before I am able to get back to the truck but y'all keep your fingers crossed for me that it is the clutch and not the tranny!

 

Well folks, sometimes in life you have to swallow a lot of pride to admit when you are wrong.....It appears that I removed my transmission for nothing! I have learned over the last 2 weeks that a 2 speed rear differential such as the one in my dump truck CAN get stuck in between Hi and Low range. It had been stuck in high range for some time and apparently it wasn't quite fully engaged, but good enough to drive....It finally slipped out of high range and into the neutral position! Granted, it did not cost me any money to remove the transmission but I now know that drivetrain noise can be transmitted through the driveshaft making the driver THINK that the problem is in the transmission. I am happy to report that the problem has been fixed and the old dump truck is back on the road for the cost of a used 2 speed motor! Thank you all for your suggestions along this journey!