Transmission wont hold 1st or 2nd under WOT

[pjnutt]

I have a transmission issue. The trans will not hold 1st or 2nd under WOT: it neutralizes. It basically revs out the motor and hits the rev limited. When manually placed into 3rd or 4th, it goes like a bat out of hell.

Any ideas on what I can do to fix? Transmission was rebuilt about 4500 miles ago, new PTC converter was put in last August, car doesn't have much mileage since then.

Thanks,
PjNutt

 

[RmvBfrFlght]

Does 1st & 2nd hold when the shifter is in the 3rd or 4th position? If so then the low/rev boost valve is likely stuck or bad. A pressure check will show this.

When the shifter is in the 1st or 2nd gear position, the line pressure is controlled by the low/rev boost valve. With the shifter in the 3rd or 4th gear position, the line pressure is controlled by the main boost valve.

RemoveBeforeFlight

 

[pjnutt]

Yes. When the shifter is in 3rd or 4th, there's no issue. I will try and pressure check it!

Thanks.