2004 TJ automatic with clunk and shudder shifting into 2nd gear

[Frankred]

Hi all,
I just drove around to try to get a video of the tach jumping up and down during the shift from 1st to 2nd. I didn't get that, but I did get a video of the slight jerky sensation (that is normally also visible on the tach). Here is a 1 minute snip of a 12 minute video. The shift in question happens at 17 seconds. You can see my phone jerk slightly and hear a sound. It seems like the transmission is changing it's mind between 1st and 2nd gear.

It is kind of absurd, but I have had this issue since I bought it in 2007. The dealer drove it around and didn't notice it. I thought it would get worse, so I kept the paperwork on the service visit... Now that I am thinking about getting bigger tires and lift (currently 2" spacer lift, 1" body lift, 1" motor mount lift 31"s), I would like to have all my ducks in a row first.

https://drive.google.com/file/d/1B7C1dmYdMam05PxipOrOzdmksZFiB2ak/view?usp=sharing (1 minute clip of 12 minute video, happens at 17 seconds) 93MB

https://drive.google.com/file/d/1AkJ0hA6qpSv58Uv0zcScuvWOE2dvL8zw/view?usp=sharing (12 minute video, issue happens at 6:02) 3GB!

I have never found any codes on the issue or had anything other than the occasional studder-shift.

Bonus points to anyone that can tell me what part on my rear drums needs grease when I let of the brakes at 0:13! lol

Thanks,
John

 

[hear]

honestly, it's kinda hard to tell what's going on with you turning & putting the wheel in the way of the tach. The shift at 0:17 does sound a little weird, but it's also coming out of a turn so there are other variables. Just get a straightaway & get it to run through the gears. Also use manual shifting & see if that recreates it more reliably.

Does it only ever happen during the 1-2 upshift? What about from 3-4?

 

[Frankred]

Thanks for your reply! I agree that video isn't a perfect smoking gun. Normally, the tach would bounce up and down a few times while the transmission makes up it's mind. That would help it be more obvious in a video. I will drive some more neighborhoods and see if I can make the issue happen by manually shifting like you suggested.
It does not happen on any other shift.

I did just replace the IAC as part of my maintenance prior to increasing my lift. I am surprised how much that has helped vs cleaning the original. I am wondering if it could be masking the shift problem I am having. I don't think it would,but maybe...