So this problem has been bugging me for a while. When I got my Accord two years ago, the first transmission when I purchased my Accord from a dealership was fried completely two days I bought it from a Honda dealer. So I took it to an independent Honda specialist who put in a used transmission. I opt to that route because a new transmission from the dealer was more than what I paid for my Accord. So I got the used transmission installed into my Accord and here's the strangest problem that I can't figure out, it shifts roughly from gear to gear when driving around. I have had the transmission fluid changed when that happen (obviously) and it's beginning to be somewhat of an annoyance because you can feel every shift when you drive it around and it makes this weird clunk noise every time it shifts while driving. What I have done to try to stop this rough shifting was tighten the belts on it and recently had a major service done on my Accord which did include a transmission fluid change (no power flushing whatsoever) and that didn't even solve it. So if any one has encountered this kind of problem with an automatic transmission or have any idea what might be or is wrong with it, would like to hear it! Thanks!

 

The shop probably put Dextron/Mercron III in the unit. This is good on one hand because there is less wear with this fluid, but at the expense of rougher shifts. If you want it to shift smoothly again, change out the fluid with some Honda Z1 or the Castron Multi Import fluid. You should see a significant difference in the shifting with the first change, but you will need to do it 2 more times to get most of the old fluid out.

The difference is the amount of Friction Modifiers (FM) in the fluid. The Z1 is loaded with FM to let the clutch packs slip more in the transmission for a slower and softer shift. This rides good, but has more wear. Smooth rides sell cars. Regular old Dex/Merc III has way less FM causing everything inside the tranny to grab more resulting in a firmer shift - this usually means less wear.

A good compromise is a quality Dex/Merc III synthetic fluid. Redline, amsoil or Mobil 1 all shift softer than the Dex/Merc III, but not as soft as the Z1, but also have low wear.

Can you verify what fluid the shop used in the transmission? That would be a good place to start.

 

Okay I'll see what kind of ATF they used on my transmission. I have a feeling they didn't use OEM ATF just to keep the cost down.