I just got back from the airport, on the way down the tranny would unlock for no reason at 60-80mph in 4th. The rpms might climb 200 or 500. It would go from say 1600 to 2000-2200 and feel like it was slipping then lock back up. Did this on the way back but then quit for the last 40 miles.

Before exiting the interstate I went half throttle and it shifted to 3rd at 70 and the rpms went to 4K, stayed there and it didn't accelerate like normal. The rpms at 70 in 3rd should have started at around 3k.

Got back into town and it locked fine at 50-55. Is my tranny crapping out? This has me greatly confused.

 

Sounds like when my Tranny went into Limp Mode when it overheated. Are you running a tranny cooler? If not, get the B&M super cooler.

 

Check for a misfire somewhere. A misfire will cause the TCC to unlock. As was mentioned, also try adding a cooler.

 

Ok will check for misfires, any particular codes? Also, what tranny cooler do you recommend.

 

What size stall do are you running? Was this the first time it did this? Did you do you change anything before you went to the airport (converter, tune, fluid change)? Or did all this just out of no where happen?

 

Stock stall

This is not the first time. Happened when I went on a 1500 mile trip in the spring, did it maybe 3 times for a total of about 1 mile on the trip. Had a frost tune done before the trip.

Did it a couple times on a 20 mile trip a month ago, which was about a month after changing fluid/filter.

 

I bet it is misfire like mentioned. It can be false misfire as well. Get someone to scan and see which cylinder is showing misfire. I had false misfire in all cylinders on mine, had to decrease the sensitivity a little bit.

 

if its not a misfire i would log for pressure manifold operations and tcc lock up and possibly the harness too. I have seen many of these mess up but if it started after tune then prolly misfire

 

You don't have an SES light on, do you? If so, check for a P1870 (transmission component slipping) code.