M915 A1 hill climb

[kinghomes]

Just tried to bull a 15% grade pulling 48k lb Track Hoe on lowboy. Had to back down. Any ideas on hill performance?

 

[NDT]

You are saying with full throttle in first gear the transmission was fully stalled? Truck would not move and trans temp starting to peg?

 

[kinghomes]

Yea, I wounder if I am not getting full fuel. I was pulling a steep grade. My guess is around 15%. I was pulling a 48k pound tractor on a tri axel lowboy. If that is all she got I got to get another truck.

 

[Castle Bravo]

The -10 TM says 17% grade at GCWR (105,000 lbs) so it *should* be capable of that and more... hmm.

 

[kinghomes]

Maybe my filters are clogging. Unloaded on flat it seems to do ok

 

[kinghomes]

Do you know of a good price on a M920?

 

[NDT]

My 915A1 will spin tires trying to pull a immobile object so I suspect you have PT pump problems.

 

[kinghomes]

I just stopped moving forward. I did not watch the trans temp but the trip to the hill was only about 1.5 miles. I was more concerned about backing down the hill at this point than looking at the gauges. I sure temp must have been rising but I don't think I was near hot.

 

[NDT]

Put a boost gauge on her, that will tell the story. Should be 20 psi or more. Sounds like you have zero. A 920 is the exact same engine.

 

[kinghomes]

I did have to remove the pump once to fix a sticking plunger on the pump. What could have gone wrong with the pump ? Plunger again any idea on how to diagnose pump. It does just have one fuel filter? It is acting like a dog. Wont come close to spinning tires.

 

[kinghomes]

Where should I read 20 psi?

 

[quickfarms]

The allison is a great transmission when driven and operating correctly. Is this allison operating correctly, has an allison tech verified the operation?

My trucks will not get up to temperature unless I block the radiator. Was the transmission up to operating temperature at the start of the hill?

What gear was the selector in?

Does the converter lock up work?

How many times does the transmission shift during normal driving?

Is the transmission set up to start in first or second gear?

 

[kinghomes]

I pulled the selector down to first as I started up the hill and held WOT. the trans, on its own shifted into second (I believe). Then when the hill slowed me the trans shifted ( I believe) into 1st. I had just idled the truck for about 15 minutes prior to starting my 1.5 mile trip to the hill climb. On the way to the hill, I placed the gear selector in 3rd and drove mostly WOT fore the 1.5 mile trip. The temp today got up to about 70

 

[kinghomes]

No Allison tech has looked at this transmission since I owned it. But my belief is the transmission is operating normally. Since my rpm dropped precipitously during the climb I do not suspect transmission slipping. Torque converter seemed fine. No funny smell.

 

[kinghomes]

I guess I would guess this truck is either operating normally and I just have it overloaded or over graded or both. Or, I have a fuel issue. Maybe I should replace the fuel filter and put some a half diesel half diesel fuel cleaner in the new filter?

 

[kinghomes]

Anyone Know hoe and where to test fuel pressure. I think this truck only has one one filter and one pump.

 

[NDT]

Where should I read 20 psi?

In the intake manifold after the turbocharger. There is a tee fitting to install a gauge on the drivers side of the engine. Sounds like your PT pump needs to go in for it's $500 overhaul. Again, the boost pressure will tell the story.

 

[kinghomes]

20 psi? any way I can fix it. Need to be on the job. Yea the way it was dragging I think you may be right. You think it has bad seal bypassing?

 

[NDT]

20 psi? any way I can fix it. Need to be on the job. Yea the way it was dragging I think you may be right. You think it has bad seal bypassing?

It's probably the aneroid valve, but fixing that is not in my skill set. Google "repair Cummins PT aneroid valve AFC valve"

 

[kinghomes]

thanks