Allison Transmission Maintenance
in Staunton, VA

“Customer concerned about CEL in dash/engine runs rough; scanned for stored codes and found a 5volt reference fault code and fuel rail pressure below spec fault code. Monitored fuel rail pressure at idle and under load and found sporadic changes but no consistent data. Back-probed into the fuel rail pressure (FRP) sensor and found .8 volts on the 5v ref wire, checked 5v ref at PCM and found the same. Check the other 5v ref drivers in the PCM and discovered that they were reading the correct 5v. Unplugged the FRP sensor and back-probed at the PCM and the 5v ref was restored. Measured 5v reference at the FRP sensor connector while unplugged. Replaced the FRP sensor and re-scanned for fault codes. Test drove with no issues.”

“Oil leak in ISM Cummins engine. Remove hood, radiator assembly and front accessory drive components to observe engine oil leaking on the backside of the timing gear housing. Remove gear cover and timing gear set, remove Jake Brake assembly and rocker arm assembly, remove camshaft. Re-seal gear housing and re-set overhead to OEM spec.”

“Bobcat skidsteer threw the front accessory drive belt. Removed engine mount in order to lift engine and slide idler pulley out. Replaced idler and belt.”

“Operator ran a log through the front glass of John Deere 110 excavator. Removed sliding door, removed/replaced front window glass.”

“Low power/acceleration/boost in Ford F350. Hooked up the scan tool and check for codes, perform visual inspection in engine bay for obvious sign of boost leaks, perform injector buzz test which came back clean with no codes, perform injector kill test, all normal there. Test drive up the road, engine hot, loss of power/boost pressure, replaced turbo outlet boost hose and engine air filter, check turbo actuator, test drive with same result, scan tool command the VGT position and felt much better, remove EGR valve and found blown O-ring, replace EGR valve, works fine.”

“Truck feeling sluggish on acceleration and pulling to the right while driving, plus some sticking when coming out of park. After parking, heat and smoke coming from the passenger side brakes. Checked over brakes, took them apart, piece of the calipers broke off, had possibly been broken for a while. Some heat damage to brake pads. Replaced calipers and pads, cleaned up rotors, took for a test drive and burnished brakes. No problems, all previous symptoms gone.”

“Bolt bounced in the road and punctured radiator on the road. Driver added coolant and limped to a stopping place. We pressure tested radiator, definitely not holding pressure! Ordered replacement radiator, removed/replaced same day.”

“No crank no start, measure voltage on sig pin of starter solenoid; 9.5 volts. Unplug sig wire at solenoid and measure V at signal pin in ctrl module in firewall and at sig wire in solenoid; all 12.2V. Reconnect sig wire at solenoid and re measure; 9.5V, not enough to make the solenoid cycle the starter, enough to make it click. Cleaned all body/chassis/engine grounds and treated w/ dielectric grease. Re-test sig pin at solenoid; 11.7 volts. Starter/solenoid works 10/10.”