Random A4LD issue...insight welcome...

[BrokenWrench2011]

So my '92 Exploder was spitting out heavy grey/blue smoke at idle and under hard acceleration. Pulled a vacuum with a manual vacuum pump to the modulator and at 8"/hg ATF spewed up into the vacuum pump. Changed the modulator as it would not hold a vacuum. Now when the X is cruising on the freeway at 65 mph in ither 3rd or 4th range in kicks into neutral under hard acceleration when trying to pass a vehicle that is in the way. The tachometer will jump from 2500rpm where is usually stays @ 65mph then jump to 3500rpm and it feels like the vehicle is in neutral and it slows down...then it feels like it is trying to engage the tachometer jumps down to 2500rpm again then it feels like there is powerflow through the driveline to the wheels. when it feels like there is connectivity in the driveline when the accelerator is stepped on slightly it kicks out and the tachometer jumps up to 3500rpm again. I let the vehicle coast to a stop and it is jumping back and forth when I come to a stop in the emergency lane when the range selector is gone from Park to Drive again there is connectivity in the driveline. Then the X can continue on the road. Shifts from dead stop feel smooth and firm. The issue seems to be isolated to 3rd and 4th range when trying to pass something at 65mp.... Any insight as to what this might be would be fantastic. Thank you in advance.

 

[BrooklynBay]

Welcome to this forum! Did you check the fluid level? It might be a little low. Was the bore cleaned with a wire brush before the pin was reinstalled? Do you have an adjustable or non adjustable modulator?

 

[BrokenWrench2011]

Thank you for the welcome Mr. BrooklynBay. The fluid level is in the crosshatch on the dipstick at normal operating temperature nice and pretty red. The vacuum modulator that was installed was not adjustable. I will try and clean the bore for the rod out with a wire brush and see if that makes a difference. The rod was unobstructed and moved in and out of the bore freely. The mystery still remains. I do appreciate your insight and ideas. I was just trying to wrap my head around what was going on in the valve body durring those moments when it went into neutral and then engine RPM dropped and connectivity in the driveline was felt...then it would go back to neutral then back to powerflow in the drivetrain. Just trying to understand what is happening to be able to aide in the fixing of the X. Thank you again.

 

[BrooklynBay]

Sometimes the servos dry out from the heat of the exhaust system, crack, then lose apply pressure. You could replace them, and adjust the bands.