Transmission bangs into 2nd gear

[Tahoe7689]

I have had trouble with the transmission (I think) shifting properly, and I thought it was fixed when I did the seafoam. It was running the best it ever had, then a few days after the treatment it started to bang into first gear again and the vacuum brake asst. seemed to lose power. So I did the seafoam again, but it didnt really fix the bang, but did fix the brake problem and it is running better. Is this problem a trans prob, or an engine prob and what should I do??? Please help? thanks!

 

[JennaBear]

What year Tahoe, how many miles?

 

[Tahoe7689]

2003 LT flexfuel 4X2 5.3L, around 107,000 miles

 

[Tahoe7689]

It seems to not bang if I give it full throttle just fyi

 

[JennaBear]

What are your mods? Definitely sounds like transmission

 

[Tahoe7689]

K&N FIPK and high flow cats. Right after I did the seafoam it ran perfectly, no problems, which leads me to think it is something else. But about a week later it started to run funnny again.

 

[Tahoe7689]

I also had the trans fluid changed a couple of weeks ago, and it did nothing.

 

[andiamo]

I had the exact same problem shortly after I bought my 2003 Tahoe with 77,000 miles on it. The transmission shop that I trust called it a flaring shift. The tranny shop took our truck to the Chevy dealership and had the transmission computer reprogrammed. Apparently there are several different programs they can put in to correct different shifting issues. I think all of these fixes were linked to TSB's. It has been two years since this fix was installed and I haven't noticed any degrading tranny performance issues. Going slow, you can still notice a slight kick when shifting into 2nd, but nothing like it was. Good luck.

 

[Tahoe7689]

ok thanks!