shifts to neutral when passing

[sweeda]

When passing or accellerating on the freeway on ramp HARD! but not WOT the truck power to the ground stops!(the momeantem) RPM's JUMP over 4200 (at least that is what I see when lift off the GO pedal. ) it could be higher. Then step back in to it and it will slowly accell to high gear. Then all is well again. I must go to 4th lock-up or stop to get it back to 1st gear before normal trans shifting resumes. 48RE with ats triple lock conveter and valve body. On the lower settings of smarty it happens MORE frequintly with less speed and throttle. has anyone had this happen to them. any help would be app. Dealership wants to remove disassemble and check IF there is a problem. On my dollars not theirs due to aftermarket T/C. Took truck a very good trans shop and they adjusted the T/V cable. This made the truck run very good but can not stop this problem. if you can please help

 

[basilry]

I have the same problem with my truck. It only happens when I punch the truck. It will all of a sudden seem like the truck goes into neutral but with the rpm's climbing until I back out of it then it goes into gear. But if I gradually floor the truck it will not do it, just when I punch the truck. My transmission guy said it has to do with the computer controlled shift points and the increased line pressure screwing with the computer. I still need to get the truck scanned. I have not had time to research this problem any further but any help would be appreciated also. I know there are a lot more built auto trucks out there who might have had this problem and may know a cure for us.

 

[sag2]

What is the condition of the fluid? You may have smoked the direct or OD clutches from the extra power of the Smarty. If you get into WOT it probably downshifts into a gear that can hold the power.

 

[JFaughn]

My 94 [ not computer controlled ] does the same thing .
I do not know the history of trans , but I have changed fluid & adjusted bands .

 

[razrbakcrzy]

It sounds like to me that you are likely over coming the fluid coupleing of the torque converter. You may be producing more torque the the stock TQ can handle and the fluid coupling just gives way until you back out of it then the fluid coupling can resume its job.



It's kind of like cavitation on a boat, If you are in a really powerful boat and have the motor tilted up a little like it is on plane. Every time you hit the gas the prop will just break loose and spin not pulling at all. On the other hand if you were in a smaller horse power boat, it could slowly pull until it got up on plane...