01m AUTO TRANNY efficiency vs ATF LEVEL?

GdB

Veteran Member
Joined
Sep 5, 2005
Location
Cypress, California, USA
TDI
Golf IV swap 2002
Wow! Here is the difference between a 1qt overfilled 01M Auto tranny, and properly filled.
Hwy only, > 55MPH: 86% -> 95% (10% improvement)
Mixed Hwy (~10miles) and street (~2miles): 72% -> 87% (15% improvement)
I was getting bad MPG and sluggish response at low throttle settings, just off idle, so I was trying to figure it out.
I thought my auto tranny was going bad, so I did a VAG-COM log of the engine blocks 001 and 006, and combined the data with an improved version of the 9624MPG spreadsheet that I downloaded from TDIclub. My sample rate was very low so accuraccy was limited. So I averaged over all the data to fix that. I calculated mechanical efficiency from power (measured, drag, & mech. required).
So I confirmed that my tranny was a pig, very inefficient! A few days later, I just happed to notice the correct procedure for filling the tranny, "01M 4 Speed Automatic Fluid change Procedure.pdf" or "autoFluidchange.pdf". I realized I goofed because I assumed it was like another auto tranny I had done. Since I knew it was overfilled, I just had to drain out a bit. For me, the VW procedure is overly complicated with the temp stuff, using VAG-COM to measure temp! My locale temp. was close, and the engine was cold, so all I had to do was put the allen wrench on to the drain plug, and lose 1qt!
So I drove it and notice the sluggishness had improved a lot, and the tranny seems to behave better in general. Was it just real, or was I thinking wishfully? And how much will my milelage improve?
So I redid the VAG-COM log and plugged it into my xls file and wow!
I think my injectors might still be a little clogged, since part thottle is still not a responsive as my wifes 2003 Jetta Wagon TDI, Auto
Finally I should now do 10 to 15% better than 35MPG! Maybe 40MPG?
 

GdB

Veteran Member
Joined
Sep 5, 2005
Location
Cypress, California, USA
TDI
Golf IV swap 2002
Never Mind

I REALIZED I UNDERFILLED IT ~1/2 TO 1QT BY NOT RUNNING THE ENGINE. So I redid the ATF level correctly. Since my shifting is too slushy, and I liked everything I heard about the line pressure mod (particularly the 01M life extension), I also did the line pressure mod. So, again, I redid the VAG-COM log and plugged it into my xls file.
I have not gotten as good results, but I also noticed a lot of variation from one drive to another. The low sample rate vag-com problem may be partially responsible.
The final sketchy results:
ALL >55
MPH MPH
71.9 - 85 1qt overfill LOG: long data run
86 - 96 1qt underfill? LOG: long data run
75.2 - 97.6 ATF LEVEL with ENGINE RUNNING LOG: short data run
+ LINE PRESSURE MOD
75 - 89.2 ATF LEVEL with ENGINE RUNNING LOG: short data run
+ LINE PRESSURE MOD

I am tempted to conclude overfill does reduce efficiency maybe 5%, and underfilling may get you anther ~10% for a short time until tranny death.
But I can't be sure unless someone does this kind of experiment with a higher sample rate vag-com log.

I wish I could lock up the 01M with a "sport" button or ? KERMA, how did you do it? If my 01M ever blows, I will do a manual swap for sure! I miss not choosing at what RPM, throttle to shift.
 
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