Have questions about my tranny shifting! Please help!

[JCHALOSUT]

I have searched this forum for answers, but have not been able to find someone having the same problems as I am. I am new to the 4r100 (just sold my 6.0) and it's shift patterns so any help is greatly appreciated! I just purchased this 1999 7.3 with 110k on the clock. I took it in to have the transmission serviced after I purchased, and my diesel mechanic said the fluid didn't look so great and there were some metal shavings on the plug. Basically, my problem is as follows. When the truck is cold it shifts great, but after it heats up my 2-3 and 3-4 shifts become loopy. It doesn't shift hard and the OD light is NOT blinking or anything like that, but it will shift from around 2.5k down to 1500 on the 2-3 shift making it extremely hard to get on freeways etc. It is almost like it immediately drops in to OD or the TC is locking. Same goes for the 3-4 shift. What could my problem be? Anybody have similar symptoms? I was told that a custom chip might fix this as it could be shift strategy? Any help would really be appreciated!

[JCHALOSUT]

no one has encountered this problem before? Any transmission guys shed some light on the issue?

[ipz2222]

tc comeing on right on top of a gear change can happen. It sure kills the power. Some programmers do change that, it is normal.

[orng1]

I think I have a similar problem as you. I was told by John Woods I have a bad input shaft. Been babyinb it for two years now. Luckily it's not my only vehicle.

[sputnik801]

Mine used to hunt between 2 & 3 and after getting into 3rd, depending on the RPM, not downshift correctly. After I installed a superchips program, the shifting changed for the better.

And now (of course) I'm getting a slip code, but never feel it slipping. It has a rumble sometimes.... Hoping its nothing major. Good luck with your issue.