I've done a couple pulls now running the Co-Pilot in Kill-mode and had a some shift wierdness issues.

The first situation is where the truck pulls ok though 1-2-3 but then it won't hold 4th and unexpectedly downshifts back to 3rd (low-range).

The second situation is similar, but it pulled fine in 1-2, but when it hit 3rd it went straight into 4th without pulling through 3rd's normal RPM range. When this happens you have no RPMs in 4th and you must pull back to 3rd to save the pull. It also barks the turbo pretty badly.

I talked to Nick last night who's pulling in Northern-Cal and he just had the first situation happen to him last night.

Anyone know how to prevent unexpected down/upshifting? It never happened prior to running the CoPilot. I will say that for Diesel Power and I both we were always in Drag-Racing mode with T/H set.

Doug

Well, I won't be of any help other to say with Casper, the action of the Copilot is not repeatable. It might do the same thing 3 times in a row, then short-shift the next time.

The only thing I could possibly suggest is that you do a few 1-2-3-4 WOT blasts. Shut off the engine each time you do it. Seems to make it act more predictably.

Maybe you need to buy more electronics. :eek:

I haven't seen this dicussed yet.

http://www.atsdiesel.com/ATSWebsite/ProductsGM/PGControl.asp

Maybe you need to buy more electronics. :eek:

I haven't seen this dicussed yet.

http://www.atsdiesel.com/ATSWebsite/ProductsGM/PGControl.asp

To bad it isn't released yet :(

I thought sled pull was 1 light to the left of full not all the way to the right. That is drag race mode. I doit that way and works great.

I thought sled pull was 1 light to the left of full not all the way to the right. That is drag race mode. I doit that way and works great.

:exactly: At least that is what Clint told me when I asked about sled pulling settings.

Everything doesn't have to be set on kill for the best results. Try some different settings.

Main level = How much xtra pressure to the clutches.

Sub level = When the xtra is applied based on boost.

Perhaps "too" quick of a shift is dragging the motor down under the xtreme load of the sled which in turn causes it to get under the turbo briefly, which could cause the wheel sped to drop, which the Allison interpets as needing to down shift.

Perhaps someone with a Tech 2 (Nick) should be snapshotting his pulls. :D

I wonder what Mtomac thinks? :help2:

I wish I could be of more help but I have an older copilot without the fancy race modes. Also, I haven't ever had a shortshifting issue or anything in T/H mode with the copilot on.

A lot has to do with load and wheel speed along wityh how much power you have to back it up, and TRACTION.

I've done the selector in D thing and had it overshift and snuff the engine.

I've had the selector in D and had it make what seemed to be one huge shift (everybody thought I ran Hi range) int 4 and ran down the track at 2400-2600RPM until it snuffed at the end.

I've found that having the selector in 3 and manually shifting to 4 IF the power is there, and WHEN the engine is ready to back it up is the best way to do this. I don't think that it really has anything to do with the copilot. Just turn the copilot up to max assist and run it. I'm thinking what you are experiencing is like the end of a burnout when the trans has overshifted and the tires catch up...

Doug, are the shifting issues happening when taking off in D?

When I had the quick shift, I put it in Drive with the ODLO engaged. That's when it quickshifts through 3rd into 4th. During these runs I've had very good traction with a lot of loading on the engine. My CoPilot has been on the dragrace mode when pulling since I've had it.

Kennedy I was thinking exactly what you suggested; put it in 3rd and manually upshift when the RPMs are right.

Doug

Kennedy has a good point. We may be at the mercy of the speed sensors. Think about it:when your traction changes abruptly at full power and speed sensors read a slow down, TCM just might drop pressures or downshift not knowing you are under full power because it sees geartrain slowdown. We have seen similar problems with the Duramax doing a burnout in the bleach box. If you do the burnout and stay into the throttle after you come out and gain traction, wheel speed comes to a stop, throttle is to the floor, TCM thinks no load and drops pressure, and C1 is history.

No need for ODLO in 4x4 low range as it will not engage. The 4wd low in D is very much like doing a burnout. The trans shifts based on shaft speed and gets out ahead of the power. I did this at the Loyal Corn Fest Pull last year and it nearly snubbed. Rookie instinct had me swat the selector to 3 rather than stop before the restart cones. Ended up getting beat back to second place as the recovery was just too slow.

Unity Pull I was watching everything, made sure I set up correctly, BUT forgot the selector again, and it made what they described as one shift (they thought I ran Hi) and pulled down the track in 4th till the grousers dropped and the turbo barked then snubbed the engine. The snapshot had the engine RPM at 2400-2600 and dropped to 908:eek: before it snubbed. Won by 5' there over the truck that got me at Corn Fest.

Most stock turbo Dmax's will not have the beans for 4th on a decent track unless they are sprayed. Then I suggest selecting 3rd and manually click it up, but be sure that you have some RPM overrun available...