Transmission issue or cat converter going out?

[bigdj75]

I just bought this truck 3 days ago. I've noticed when I first take off and ease into the throttle and then back of, the transmission shifts down and I get this weird sound and performance. It almost feels like the trans is shifting between two gears and will only get past it, if I give it more gas and accelerate. The sound is as if the engine is smothered, which is why I mentioned the cat converter. There is also this rattle, what sounds like a heat shield or something being loose. The truck has 65K on it. Any suggestions? I did buy a warranty, since it is used...just trying to see if anyone has experienced anything similar. Thank you for your time.

 

[KGBIGCOUNTRY]

Welcome, have you checked the fluid?

 

[truckin151]

Welcome! Start out by doing a full maintenance check. Oil fluids clean the TB and check and/or replace the spark plugs and check the trans fluid. Another thing it could be is the second prime down shift.

 

[bigdj75]

I did check the fluid and it was a 1/2 qrt low, so I added that and no change.

What is the second prime down shift?

 

[truckin151]

Clean the throttle body and see if that helps the bog

Second Prime is an overdrive gear, when you down shift from 3rd it goes into second prime, its a weak gear and bogs things down abit which is why when you gun it at highway speed it bogs down before shifting out of gear.