Subject: Right - we don't know all the reasons some ZFs use only this special fluid... Author: davidsoine : member since September, 2004 : 870 posts Posted on: 2005-02-06 11:55:36

Phil said: "When the ZF 5HP series transmission was developed and tested, I'm sure the engineers had reasons for using a particular fluid. But do you know all the reasons why that particular fluid? I don't."


Exactly the reason that the guys I trust will use the EXACT fluid the trans (& powertrain) was developed with. No one else has the time to understand all the tradeoffs.

I don't know how Valvoline figured out that some fluid of theirs was equivalent. But I have an idea of what they might have done.

I also have an idea what they did NOT do - which is run durability testing on our specific trans, design all the moving parts and bearings with this special fluid in mind, develop the powertrain calibration checking all the 100 or so shift events that one has to test to be sure everthing is acceptable, run a fleet of vehicles through accelerated key life testing, etc, etc, etc.

Understand that my view is biased - being an engineer with an auto company, and sitting beside guys that have much more experience than I in these issues. In fact as I write this I am at the home of an engineer that developed some of our shift quality testing and analysis methods (used during calibration development). So everyone please take my report with a grain of salt.

I'm not saying the Valvoline fluid won't work - it may work great. There may be hundreds of shops successfully using it on our trans. I'm not getting the feeling that that is happening, tho.

best,

Dave
97 740iL

• Valvoline ATF letter - pdef1949 2005-02-04 07:56:08 (38382 views)
  • The PDF original of that letter from Valvoline is on e38.org (url) - DavidC 2005-02-05 13:25:29 (2196 views)
  • Phil, are you certain about that 8 to 10 liters on a drain - dickschneiders 2005-02-04 12:16:21 (1392 views)
    • Re: Phil, are you certain about that 8 to 10 liters on a drain - pdef1949 2005-02-05 09:44:51 (1210 views)
    • I'm sure glad I had 8! I juuuust got into that 8th liter. - davidsoine 2005-02-04 21:46:00 (1088 views)
      • Re: I'm sure glad I had 8! I juuuust got into that 8th liter. - pdef1949 2005-02-06 10:11:37 (1133 views)
    • I used 8; 7 would probably have worked - cosmo 2005-02-04 13:17:11 (1102 views)
      • When I did it, the old fluid was also quite dirty, so I am - dickschneiders 2005-02-04 15:04:17 (1215 views)
  • Thanks! Curious what their 'in-house testing' entailed... - ChicagoE38 2005-02-04 10:54:32 (1179 views)
    • LOL! Note - meeting&exceeding the 'specs' is not the same as... - davidsoine 2005-02-05 10:58:39 (1593 views)
      • Re: LOL! Note - meeting&exceeding the 'specs' is not the same as... - pdef1949 2005-02-06 09:56:25 (1432 views)
        • Right - we don't know all the reasons some ZFs use only this special fluid... - davidsoine 2005-02-06 11:55:36 (1763 views)
    • Re: Thanks! Curious what their 'in-house testing' entailed... - pdef1949 2005-02-05 09:46:55 (1260 views)