Engine/Transmission (1994 - 1998) Killed the Cummins 12 valve

[GROBBINS]

Funny that you mention that....a trusted mechanic quoted that repair back in 2017 for a couple grand. I was expecting to see it leaking. Actually, I'm disappointed to loose his trust.

 

[BigPapa]

Nah, it's a pretty common misdiagnosis. Pretty much any oil leak on these trucks will run down the back to the adapter plate. From below it looks like a rear main leak. You have to start at the top looking for oil leaks.

I've seen fellows replace a rear main "just because I'm there" only to have the new seal leak from a bad seal or an improper installation as much or more often than I've seen an actual failure of a rear main on a 5.9. Mine had over 500K on it when I sold it and never a leak. Unless you see LIQUID oil coming from it, leave it alone. They will seep JUST ENOUGH oil sometimes to gather clutch or starter dust, but that's not an actual leak and I'd leave that alone as well.

 

[GROBBINS]

Nah, it's a pretty common misdiagnosis. Pretty much any oil leak on these trucks will run down the back to the adapter plate. From below it looks like a rear main leak. You have to start at the top looking for oil leaks.

I've seen fellows replace a rear main "just because I'm there" only to have the new seal leak from a bad seal or an improper installation as much or more often than I've seen an actual failure of a rear main on a 5.9. Mine had over 500K on it when I sold it and never a leak. Unless you see LIQUID oil coming from it, leave it alone. They will seep JUST ENOUGH oil sometimes to gather clutch or starter dust, but that's not an actual leak and I'd leave that alone as well.

Thanks for the reassurance.

 

[GAmes]

Thanks for the reassurance.

Do you need more? At 800k mine wasn't leaking when the engine was pulled for rebuild.

 

[DRAG DIESEL]

Oh those quality factory welded on pads.... Most of the aftermarket converters a void of these, stock flexplate is ok for mild builds and standard rpm ranges. Make sure you get a new damper on the front of the crank too, they often go overlooked and the flexplate takes the beating.

 

[raxley]

I like my Goerand Bros parts that's in my 2005 transmission.

 

[GROBBINS]

Good morning Fellas,
I thought I'd update the thread and let you know that I finally was able to get the parts needed and trans back in the truck. Thanks also to GAmes for sending me his spare flexplate he had, much appreciated! It took me a bit to find missing hardware and piece it all back but it was a good learning experience. Just yesterday I started the truck up and added trans fluid back into it. Boy, I sure do love the way this engine purrs! While out on my test drive with the truck, I wasn't able to do more that 40mph. From a stop, the trans shifts from first to second just fine and then just revs out. No shift to 3rd or overdrive.
I did notice that upon re-installation of the trans, that my TV cable was shot. This is probably why the trans has lasted me so many years. Anyway, the truck is now drivable, at least in town on short trips until I figure out what the shifting problem is. If I have to take the trans back out I will be able to do it relatively easily. Thanks again for the help.