Just got 05 granite tri axle for dirt work with T310MSR trans. Worked good for first 4 days. Monday went to work intending to service truck Monday nite. Well, going down road in 8th ( top gear) all of a sudden I got grinding sound and lost all high range gears. Limped 5 miles to Mack dealer in low range and discovered previous owner must have had leak and trans was almost out of oil. Filled it to go dump load but still no high range. Best guess before it comes apart is rear of trans but I'm hearing a LOT of bad news with this trans. My question is should we fix this one since clutch and lower gears work great now or just do the fuller 8 low low conversion and have a more reliable truck. It has 427 motor like rest of our trucks and 310,000 miles. Trans came apart at about 150,000 miles, making me question reliability. The clutch is relatively new. Reliability is very important for this job. Looking for advice on take the chance and fix or what's required to convert. I know trans, shifter, bellhousing. I'm guessing complete clutch too. How about driveshaft? Thanks in advance y
