I have really noticed what feels like the transmission slipping when it is trying to shift from 1st to 2nd gear under moderate to WOT. The RPMs will actually go down while accelerating and then start to come back up before shifting into 3rd. It seems to downshift into second fine when I get on it under around 68 mph. It doesn't seem to be as noticable without the preadator tune and I would just return the truck to the stock tune for now except I need that tune to run my e-fans. I am hoping to be able to save some money and buy Hptunners and a laptop as soon as I can.

I am just wondering if it sounds like the transmission is about to take a crap soon or if there is something else going on? And the truck has about 95,000 miles on it and as far as I know it still has the original 4L60E I have only owned the truck for about 5 months.

 

I don't think it's tuning causing it. The problem sounds hydraulics related to me.

The hardest upshift for a 4L60-E to make is the 2-3. During a 2-3 shift the 3-4 clutch pack has to engage while the band has to disengage at the same time. If the hydraulic circuit to the band is not releasing pressure fast enough then what you are describing is the result. Basically, if the band stays applied too long during the 2-3 shift, you will get a moment of fourth gear until the band lets go and then you end up in third until the 3-4 upshift where the band gets reapplied.
I would suspect that something is wrong with the valve body. Unfortunately, a lazy apply or exhaust circuit will accellerate wear on the friction materials it's controlling.
Did it start doing this suddenly or was it a gradual onset?

 

Your discription sounds like a definate possiblity for my problem since it does seem like it can't decide what gear to shift into until it finally is ready for 3rd. It has been a gradual onset. As I said I have only had the truck for 5 months now, but the problem didn't just start all of the sudden or anything. I put the corvette servos in it soon after I got it because I wanted better shifts and it seemed to help some at the time, then after I got the predator tuner I started to notice the 2-3 shift felt worse. I kind of suspect that it may be slowly getting worse.
Any suggestions on what I need to do to deal with the problem? I half expected the tranny not to last very long for me with the milage on the truck and I have considered purchasing an FLT but I was hoping to be able to get by until I can save up some more money and have warmer weather to do the swap in because there isn't enough room in my dinky garage.

 

ttt...