379 Transmission Issue

Who Tuned it, Leon ? He was the Detroit man on here years ago but vanished. However, the horsepower you claimed doesn’t add up to the the torque numbers. And not to mentioned the clutch, was it custom built for your specs ? I’ve personally never heard Peterbilt supplying that high torque of a clutch.

 

I also find it Interesting you think you need such a heavy clutch. My c-15 was around 650 maybe more and I just ran an 1850 clutch no problem. And I abused the crap out of it. I wanted to put in a 2050 or maybe it was 2250, I don't remember, but my Pete parts man said the linkage in a pete wouldn't hold up to the pressure and would wear out stupid fast. Again I dunno

 

I run a 2050…so I hope it’s the 2250 that wears the linkage out quickly. I do know the 2250 is fine splined input. They were handing out bargains on 2050’s the day I bought mine is only reason I didn’t go 1850. Mine came with a 1650 from factory. And it’s had a couple improvements but it dang sure didn’t bump the torque that much. Makes me wish I had a 12.7 Detroit

In all honesty I would bet by those numbers it probably was run on the dyno. And I would not let them morons touch my #### if they do not have enough sense to use the 1:1 or direct gear of the trans. The dyno is programmed to calculate HP and torque in direct.
Speed of drum at X brake pressure =
Lots of folks want to just pick a gear and it doesn’t work like that. And if they do not have sense enough to know that what else don’t they know. I wouldn’t take the risk to find out. A 12.7 is a good engine but it’s not a torque monster. There is no replacement for displacement.

 

That vibration iyour feeling is from all that HP slowing chewing away at your fly wh wheel bolts
With that kinda HP & torque the OEM bolts wheren't designed for that kinda power
You better talk to the place that dynoed your motor and see what they recommend for bolts.

 

I bet they would recommend using cut off taps as studs with the corresponding die run down over the top as a nut. I mean if they bought a dyno they knew nothing about and didn’t read the destruction manual.

 

Let’s see the slip? I have seen 650 to the wheels on a 12.7 ddec 3. But 2050 was all the torque it made.

still #### respectable. But not 800 at the flywheel and 2850