4th to 5th hang up

[quinton]

Having a problem where at any throttle percentage going into 5th the truck hangs for a split second then shifts. Just started happening a few days ago. Only thing I've done was put a cat fuel filter on my air dog. No codes at all. Drives great other than that small Hiccup. Any ideas?

 

[S Phinney]

Log just to check that there isn't any fuel pressure or delivery drops.

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[quinton]

Will do. I did reset taps also with no fix.

 

[quinton]

Here is a vid of it happening twice. Watch the Rpms jump at around 55mph. The second time is a little more throttle and you can see it better. Logs looked fine also.

 

[quinton]

https://youtu.be/eLNvznOCavo

 

[JoshH]

Looks like a shift flare to me. I'd be worried if it just started doing this out of the blue, but you might try changing both filters and putting new fluid in it. I would probably try doing a fast learn on it too (the GM fast learn the Tech 2 does).Do you notice anything weird with the 2-3 shift? Out of curiosity, what did you use for clutches and clearance in the C3 when you built it?

 

[quinton]

All other shifts are great. This is the only time it does it. Used reybestos clutches from suncoast. Don't remember the clearance but I went off of what they recommended. I'll have to get the papers back out and look.

 

[JoshH]

How does it feel going into reverse?

 

[quinton]

Great. Everything is great other than this one point. No weird noises or anything. I'm gonna through a stock trans tune in it and see what that does.

 

[JoshH]

You didn't change anything in the ECM?

 

[quinton]

No ecm tunes have been the same since I installed my s475.

 

[quinton]

Put stock Tcm tune in and couldn't feel it. Hard to tell though being a slug going down the road. Lol. Might have raised part throttle shifts to high or had the downshifts in the same area causing it to do that. Not sure if that could effect it but I will start off with the stock tune and gradually go back up again and see what it does.

 

[quinton]

Believe I fixed it. Must have been in the Tcm tuning. Not sure what exactly happened but only thing I can come up with is a mix up of up shift and downshift at the same time? If that's possible to do. I have had to do a lot of adjusting in the Tcm to make this turbo street able.