03 2500HD 5.7 - is my TC bad? Have to really press pedal to get power

[SavedByGrace]

Ive been trying to chase my low accel issues for ever and continuously hitting a wall. Ive tried so many things and I cannot find a smoking gun. Took the truck to AAMCO 3 weeks back and the main trans guy took it for a spin and commented there is DEF sth wrong, seriously low on accel- esp since i put in 456 gears, he said it should be snapping our heads back.. its lazy as heck!!

Is there a way I can test my TC? I changed for an ebay reman about 5k miles back - it seemed to be better for a little bit then back to what it is now - just incredibly lazy, the first 1200-1500 rpms delivers almost no power, the motor sounds like its revving/building up (almost like a blocked exhaust) but nothing gets to the wheels, its like the motor builds rpms but it doesnt make it thru.

Im wondering if the prev (stock?) TC was clapped out after 100k miles, AND the cheap ebay TC i put in my have also been a piece of junk. I dont tow much at all - mostly just highway trips to the desert and back.

Reringed the motor 8k miles back - one rod was spun so replaced crank, new bearings rings ngk plugs and timing etc. Bores were perfectly in spec. Truck doesnt use a drop of oil, zero blowby - starts and idles fine.

7.5mpg city and about 11.5 highway!!!!

NO CEL codes-

Cleaned TB 3 times
New coils
New sensors
New muffler
New Cat
New o2 sensor (NTK)
Verified fuel pressure

Truck starts drives fine, it does feel like it shifts early sometimes cruising but i can live with that.. im planning an 05 ECU swap down the road but for now Id like to figure this out before moving fwd with that.

 

[Gary Fields]

Perhaps your locations is different, but my experience with AAMXX was not favorable. Could not figure out if they were trying to pad the bill or simply did not know what they were doing. A little bit of asking around, in person and on FB came up with the same shop name. Shop owner wanted vehicle owners to be present when he took the pan off. Over the last 10 years I've had several of my families vehicles need work. One simply had low and dirty fluid. One had black fluid with silver filings. One had chunks of pump assembly and other pieces. His prices are lower than other places, but still not cheap. I don't think you can use the words inexpensive and transmission in the same sentence.

 

[SavedByGrace]

Are u talking about the same shop? Aamco is a franchise stores everywhere. This one in particular has great reviews. No customer complaints in almost 20 years.

Fwiw aamco transmission in signal hill CA. Look them up.