Jer510

I know that there are many posts about this topic and I've searched the forums for some answers but I felt like I needed a little more input. Sometimes when I'm driving during low speeds around 20mph or less, I notice a jerk when the transmission downshifts from 2-1. I have an AT 99 V6. It doesn't do it all the time. It only happens at low speeds when you are cruising and all of a sudden let go of the gas. Other than that, my car runs and accelerates smooth. Any suggestions? Also I've had the fluid flushed about 4 times since I bought the car in July with Honda ATF.

nhldogg

Tranny is going out. Flushing the fluid will help prolong the life but it is a waste of money after a while. Just start saving up and looking for a rebuild.

jdadams12

Get rid of the Z1. The Z1 is an OK base that is full of Friction Modifiers that make for a smoother shift allowing the clutches to slip. This slipping will cause more wear, but does make for a smoother ride - which sells cars. This fluid is not good for trannys that already have some wear, since it causes more wear in it's self.

Replace the Z1 with some Synthetic Dex/Merc III. I use Mobil 1 or Redline D4 - the Redline is probably better, but the Mobil 1 is plenty adequate. The car will have a firmer shift with less wear.

You can use regular Merc/Dex III, but shifts will be more firm than the synthetic.

Mine used to do it on Z1 so much that I oftentimes just put the car in D2 in rush hour so that it did not do the 1-2, 2-1 shifting. Now, it is much better on the Mobil 1 Syn.

You might also test the second gear pressure switch... or replace it. No idea if that is the issue, but it might be causing the TCM to delay the shift. A bad pressure switch can cause really bad shifts both up and down.