Hey guys,
So I am running a 1990 1HDT with a smidge less than 200k mi on it and I’m currently stranded in Alabama (luckily somewhere safe where I can work on the truck a bit). Truck has GTurbo and pump running 19-20 on boost and fitted with H151 transmission. The motor was out 4000mi ago and refreshed. New seals and gaskets, did the BEBs, rebuilt all the pumps (vac/PS/etc), new alternator new injectors, intercooler, new flywheel and clutch, new harmonic balancer …. Etc etc.
The problem started as vibration while driving that I couldn’t track down, over about 4-5 days and maybe 350mi. So it came on relatively suddenly but not all at once either. The vibration was usually worse later in the day after running up or down a mountain or running highway. In the mornings on fire roads it was not noticeable.
After a few days the vibration got worse, especially under load. Maybe there was a loss of power? The vibrations at least made it feel like the engine was trying harder.
It didn’t overheat at all. Oil pressure was steady and good.
Finally on the 5th day I shut the truck down at a store and there was a loud terrible clunk. I started it back up and there was lighter clunk on start up. It idled and revved fine. Drove it into town and shut it down and got the loud kerclunk again. I started and stopped the motor a few times in various configurations: clutch in, t-case in N, etc. It sounded like it was in the sump. Finally I shut off fuel and cranked the engine with no start to eliminate pump timing. The kerthump keclunk was still there as it turned over. I called a tow truck.
Our best determination was something crank related. Honestly it sounded like a broken crank.
I pulled the oil pan off and as best as I can tell the crank is in one piece. I can move it fore & aft a tiny bit and it all moves together. I still need to find some feeler gauges and see if that’s out of spec. But it doesn’t move very much.
I pulled a few rod bearing caps and they look as they should with only 4000mi on them. The felt a bit loose on the crank when wiggling with my fingers but I have very little experience with wiggling rod bearings. Lol. They look perfectly fine.
I’m at a complete loss at this point as to what to check next. It’s entirely possible it’s the crank main bearings but I have to pull the motor to check that. Which I can’t do here. I have to get a uhaul and drag her 1000mi north for that.
Anything I’m missing? Signs to look out for? What can I test?
Any advice or thoughts are welcome!!!
Thanks guys.
So I am running a 1990 1HDT with a smidge less than 200k mi on it and I’m currently stranded in Alabama (luckily somewhere safe where I can work on the truck a bit). Truck has GTurbo and pump running 19-20 on boost and fitted with H151 transmission. The motor was out 4000mi ago and refreshed. New seals and gaskets, did the BEBs, rebuilt all the pumps (vac/PS/etc), new alternator new injectors, intercooler, new flywheel and clutch, new harmonic balancer …. Etc etc.
The problem started as vibration while driving that I couldn’t track down, over about 4-5 days and maybe 350mi. So it came on relatively suddenly but not all at once either. The vibration was usually worse later in the day after running up or down a mountain or running highway. In the mornings on fire roads it was not noticeable.
After a few days the vibration got worse, especially under load. Maybe there was a loss of power? The vibrations at least made it feel like the engine was trying harder.
It didn’t overheat at all. Oil pressure was steady and good.
Finally on the 5th day I shut the truck down at a store and there was a loud terrible clunk. I started it back up and there was lighter clunk on start up. It idled and revved fine. Drove it into town and shut it down and got the loud kerclunk again. I started and stopped the motor a few times in various configurations: clutch in, t-case in N, etc. It sounded like it was in the sump. Finally I shut off fuel and cranked the engine with no start to eliminate pump timing. The kerthump keclunk was still there as it turned over. I called a tow truck.
Our best determination was something crank related. Honestly it sounded like a broken crank.
I pulled the oil pan off and as best as I can tell the crank is in one piece. I can move it fore & aft a tiny bit and it all moves together. I still need to find some feeler gauges and see if that’s out of spec. But it doesn’t move very much.
I pulled a few rod bearing caps and they look as they should with only 4000mi on them. The felt a bit loose on the crank when wiggling with my fingers but I have very little experience with wiggling rod bearings. Lol. They look perfectly fine.
I’m at a complete loss at this point as to what to check next. It’s entirely possible it’s the crank main bearings but I have to pull the motor to check that. Which I can’t do here. I have to get a uhaul and drag her 1000mi north for that.
Anything I’m missing? Signs to look out for? What can I test?
Any advice or thoughts are welcome!!!
Thanks guys.
