JoeMamma, how much of an incline were you on? I thought it had to be level to check tranny fluid, which is what is partly slowing me down. Is it that critical to be level?
Thanks.

 

My driveway has a small incline, I know it says level, but I figured an ounce or two over wiuld not hurt. I even had to jack it up some just to get under it. I do not have any lift installed and squeezing under is not an option, and I am relatively thin.

 

Drained the fluid and dropped the pan on the tranny. Checked and all the o-rings were in place and everything was in place and tight. It could have been sucking air around the pan gasket so I put dabs of gasket seal on it and made sure it stayed in position when I tightened it down. We'll see if the thump-a-thump remains. Thanks to all for the help and suggestions (yes, it was level and ran thru the gears and it was running) : > )

 

Please inform. Which fluid did you use?

 

Sorry for the delay, grand kids take priority. To answer the last post, I used Valvoline Max Life Full Synthetic ATF. It almost seems like the tranny is bouncing in and out of or between gears. Otherwise the truck is driving well. Not as bad as before the second drain, drop and refill.

 

This is just one more case of a ZF ATF change gone bad. I changed mine even after reading a few threads where problems due to a drain and fill arise. My 2003 had nearly 100K when I bought it so I changed every fluid in the thing per DiscoMikes write-up and now I can't hit 4th gear first thing in the morning before having to pull off the road and coax my transmission into behaving so that I can drive on the highway. I'm sure it's salvageable and just a valve sticking but now I'm going to have to run a cleaner for a few days then do a drain/fill/filter. Drive it 2 weeks and do another drain/fill and see where I stand. I will try my own advice and post results on my thread that I have going: "probs creeping up w trans." I suggest you take it easy until you remedy the real problem before you have a real fault that includes a rebuild.

 

Note that draining only removes a portion of the existing fluid, with the cooler and converter retaining several quarts. The mixing may be the cause of some of the foam, although unlikely. I've had different experiences when filling with new synthetic or traditional fluid, depending on the mix, and the subsequent changes in viscosity. The ZF modulates pressure to make smooth shifts, for which the transmission ecu adapts over time to control the shift duration, as well as managing torque output at the time of the shift. I've had good luck with Castrol trans-max, both import and regular, when I'm not sure what fluid is currently in place. Regardless, it seems as if it always takes around 50 miles or more for the ecu to calibrate the shift pressure modulation and torque management back to smooth. My two cents.

 

Does the castrol come in the general "Dex-Merc?" I asked myself if a higher-end, more specified "dex3" would make the unit behave any differently. I have read some threads where people were getting better performance from say Royal Purple brand over something else. Can Dex4 specific be used in these ZF units? I'm just starting to read on this but I know that some of you guys know all about these fluids and how they work. I would like a lesson on later model transmissions and how they function on different types and grades of fluids

 

The Castrol is advertised as "Dex III and older compatible". It's my understanding that Dex VI (I'm not familiar with a Dex 4) is backwards compatible to the III and older, and that it is a slightly lower viscosity. I happened onto the Castrol Transmax when fixing a Freelander Jatco. I've used it on the ZF ever since as well, and it seems to improve the shifting, especially on the high-mileage transmissions. Again, it does take a while for the ECU to adapt to the changing viscosity, and that includes messy shifts for a few miles.

 

Alrighty. Good info. Sent you a PM