Engine/Transmission (1994 - 1998) Question about my transmission.

[pathaymond]

While Pulling a heavy 10K load at a speed of 15 mph up a nasty hard paved hill This hill is about 1 mile long. I heard a loud metal to metal banging from my transmission. it would stop if I backed out of the loud pedal and when I applied the torque again it would come back. I am a auto and was down in 1st gear. thats where I started the hill and I just keep it there each trip. this was my 6 trip with that load in three days time. My temp was about 210 which i see each time I have to do this nasty hill. When we reached the top I shifted to 2nd and applied the torque and it was quiet. stopped and went back to 1st and it would do it again under torque. When I hit the gravel locked it into low range and 1st and finished the trip. I have tried on my return trip to make the noise occur again with no luck Fliud looks good although It is going to be changed soon. I am not stock in transmission or engine I am no way overly bombed either Just a nice mix. I do wonder about the transmission upgrades though. but that a diff issue or is it. Any ideas as to the mystery knock. Thanks for the read and sorry so long Patrick

 

[Reb.B]

engage the e-brake, push on the brake, put it in reverse and mash the pedal, do the same thing in first, . . see if the noise comes back. Don't do it for more than 10 seconds. Also when u pull the grade need to put that thing in low range, makes it so much nicer. Need to get the unlock 2 lo kit, or switch the two vacuum hoses under the truck near the transmission mount when u put it in 4 low, make sure to switch them back when u go back into 2 hi.