Like I said I am green when it comes to drag racing diesel trucks.
Evreything I have races has been manual shift-rear wheel drive.
My queston is: I assume you take off in four wheel drive, but are you in all the way down the track? Running the transfer and front axle throught the traps? Or, are you shifting out of 4wd after launch?
Could you shift out after launch and unload the mechanical burden of the front axle to increase time/mph?
Just pondering.
Thanks.

 

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starflite:

Yes, I leave in 4WD High and I leave my truck in 4WD all the way down the track until I am through the traps at which time I push the transfer case selector level back into 2WD. But, with that being said, you can shift back into 2WD after you leave the line. I have done it that way, but leave it "ENGAGED" all the way now because my trap speeds are almost 120 MPH.
On my trucks, I saw no difference in E.T. by leaving it in 4WD or shifting into 2WD after leaving the line. Your results may vary though.

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John_P

 

It never disengauges until you let off the throttle and reduce the drive line load. It dont matter where you switch at, but its easyier for the drive to do it at the end and focus on driving.

 

I leave mine in all the way down.

 

I also leave mine on all the way down as well.