CAT 16 speed trans

[cundupa]

Anyone know anything about the CAT trans? I have a M919 mixer, when fully loaded it shifts fine up to 13th or 14th. From there up it slips a bit under load. I can get it to catch if I let off the throttle. It feels fine in all the speeds below 13. Fluid is full, not hot and pick up tube screen is clean. Empty or even 1/2 loaded she runs fine.
Thanks

 

[wreckerman893]

Those transmissions were very paticular about air pressure... they will kick into neutral if the pressure drops below 80 psi.
How is your pressure while you are upshifting......you may have to take it to the Cat house and have an expert check it out.
Could be a clogged line.
Just my thoughts.

 

[BFR]

you may have to take it to the Cat house and have an expert check it out.

WM, do you often go to a cathouse when you have trouble getting it in top gear?

 

[Heavy Hooker]

The Cat 16 speed trans is a really HD trans. It has 3 counter shafts to share the load. It has a clutch on the input end and on the output end there is also a brake at both ends. The large pistons have teflon seals that can leak which will cause hard/harsh shifts. If it is slipping under load it is possibly the output clutch. There is no adjustments just replacing the friction plates. The Cat guys will scratch there heads on this trans as it was a very expensive trans no one would buy it but the Military and a few south American companies. I have repaired and rebuilt many of these transmissions years ago. Ours needed valve body heaters to operate right here in Alaska. I had a valve body failure that caused it to go in two gears at once, I had a 100K load, when the clutches reengaged the transmission case split into 3 pieces, what a mess!

 

[cundupa]

I'll watch the PSI, I think it is OK, feels like a clutch slipping unless low PSI would let it disengage just a bit? Called the Cat shop when I got the truck(know the service mngr for the truck engine div.) they heard of them and worked on some a long time ago for the reserves, but I can learn as I go too, for less $ than they get! I have a parts book for it. Any service books out there?
Heavy Hooker, do you have a D4 earth mover to go with the clark dozer?

 

[Heavy Hooker]

I do have the Cat rebuild manual somewhere. I will look and if I find it look into getting it copied. From what I remember the clutches are held engaged with springs and disengaged with air. Good clean dry air is the number one thing to keep these trouble free. Making sure the air dyer is serviced and operating proper will ensure this. My little Clark Airborne was used as a parts vehicle so I am still looking for pieces. My neighbor has a 1942 R4 gas D4 Cat cable dozer that was probably used on the AlCan Highway project. It to needs some work.

 

[armytruckdriverddsso]

I Drove M915 On Active Duty I never had one slip when air was low, I did run in to faulty engagement valve on shifting tower caused similar problems. I had to hold the valve in with my knee to get back to motor pool.

 

[cundupa]

Thanks armytruckdriver, like your quote on the bottom.

Heavy hooker, I was thinking of the D4 turnapull scraper, also a air drop machine, matched up to the clark dozer.

 

[OPCOM]

WM, do you often go to a cathouse when you have trouble getting it in top gear?

I could comment on the housing of cats..

 

[wreckerman893]

I deny everthing and demand proof.