rough 4 to 3 downshift

[monster50iii]

Every now and again when I am in manual mode manually downshifting I get a rough 4 to 3 downshift. If I let the truck downshift on its own in tow haul it shifts beautifully. Normally I'll try and go from 4th to 3rd at 2000 rpms and I experience this. It did this before my trans build and now after 500 miles or so on the new build it is doing it again. We put alto clutches in it, pump shim, but we decided not to install the new trans go kit. My trans already had one installed, could this need replacing?

Thanks happy holidays guys

 

[monster50iii]

I forgot to add when the trans was doing this before the build I added a can of sea foam trans tune and the issue immediately went away. This is what has me thinking the trim valves might be sticking a bit? I'm using valvoline dex/mercon

 

[monster50iii]

Bump

 

[bml2200]

From an engineering point of view, you may be downshifting at point that no one normally would downshift. They generally pick the ideal ranges for people to choose to downshift from to tune/design the transmission software for. That or your trans was bad from the factory.

 

[monster50iii]

I was pondering on the idea that the TCM isn't wanting to downshift that early and has hickups every now and again. It seems like it does it more when the transmission temps are above 160*ish. Everything might be a-okay? idk...