ntc350 bc cummins no power in high gears?

Did you ever get the injector number while they were out?

 

Ratio drops are the same percentage in the low side and high side. Has the fuel pressure been checked on the engine?

 

I believe the letter on end of direct dive fuller is the gear set, or ratio, of LO gear. Trucks with 3:90, direct trans, & 11-24.5s should run out about 70mph, give or take some dependent on max rpm. Is your gear ratio tags on the axle housing or the chunks? I understand wanting to sell but can you justify not to fix it. A BC350 with that set up should be able to pull out at 65 or better in flat Florida. Each gear higher requires more hp and torque to pull the same load, when the requirement matches the engines output your done. An overdrive transmission would just give you one gear higher on top and gain you nothing before it. We would really like to know what the fuel psi is on the road under load. I would thank the ones that rebuilt your fuel pump or engine would help you out. Or go to a hydrolic hose shop and and buy some pushlock hose and fittings, it's inexpensive and will take 300 psi.

 

Sorry: Skipped some questions. Tandum axles has nothing to do with it. If you want to check injector numbers you can probably do that from your recliner. If you have the serial # off the block call the dealer. They can give you the correct # and compare it to your invoice. You can probably get a inexpensive gauge from Grainger, Northern Tool, or somebody like that on line if you can"t find it local. Why is because it sounds like low fuel pressure and just because you have a reman pump does not rule it out. 2. If low check fuel pressure under load with AFC pressurized with a radiator pressure tester or test gauge connected as previously outlined. 4.If low check fuel psi with fuel line straight out of tank to pump. If still low psi is probably the pump. If pressure was good when first checked check for restriction through soliniod to head. Did you check exhaust restriction? Would like to know what you find.

 

did you ever replace the fuel solenoid?

 

I would put a restriction gauge after the water separator too. Could have a collapsed line or sucking air. You can buy good liquid filled test gauges and the rigging for around a hundred bucks. Trying to troubleshoot without gauges is well not trouble shooting but replacing parts.