Hello folks I have a 03 D/A AT 31000 miles . I am planning to change ATF myself using Mobil 1 synth. I am not planning on flushing or dropping the pan, just replacing drained fluid and filter. I figure if I do this every 10000 miles from here on I should go from approx 60% synthetic to 80% synthetic(next change at 40000) to 90% synth (at 50000) to 95% (at 60000).At that point I could go to 50000 mile interval. What do u guys think?


PS I forgot to mention I was running regular dextron3 from the dealer when truck was bought.Edited by: E=mc

Sounds like you have it all figured out, Go for it.


http://www.dieselplace.com/forum/smileys/Clap.gif

That is certainly the easier & cleaner way to do it. Let's see if this is a cost-effective way to do this.


Figure 12.7 qts. of fluid in the Allison with stock shallow pan. Each time you drain the pan and change the spin-on filter, you've changed out 7.4 qts. or 58% of the fluid - close enough to your 60%. At your next change interval, 40k miles, you're changing 58% of the fluid that is already 58% synthetic, disposing of 4.3 qts. of synthetic fluid at 20% of its service life, or a net effective loss of 3.5 qts. of synthetic (4.3 qts. * .80 life remaining). At 50k miles, you again change 58% of the fluid, discarding 4.9 qts. of synthetic, adjusted for remaining service life. And so on. Your percentage of synthetic would rise to 83% at your 40k service, and to 93% at 50k. At the 100k change, you'd achieve a theoretical 97% synthetic and peak at 99% at the 150k fluid change.


The spreadsheet I put together for this exercise shows that if you were to sell your truck at 200,000 miles, without changing fluid, your total cost of fluid changes over the life of your ownership would be $222 for your progressive change method vs. a flush and fill with 12.7 qts of synthetic now and changing then every 50k for a total cost of $212. This assumes a constant cost of $6 per qt. of Mobil 1, adjusts for remaining service life of fluid left at 200k miles (31k with the flush now vs. 0 using the progressive method), and accounts for approximately 3 qts. of lost Mobil 1 during the initial flush and fill.


So, you would save yourself about $10 in fluid and save 1 fluid change by flushing now. And, you'd gain additional miles at a higher (100%) concentration of synthetic.


Sorry - it's kind of cold and rainy here and my gauges didn't arrive in time for me to install them this weekend so i have nothing to do and I just couldn't stop myself from over-analyzing your question.

Whoa....now that was deep

E=mc, it is not that hard to flush the old out. I think Hoot has a link to the directions. Later! Frank

Thanks guys!

There is never a lack of Engineering here. http://www.dieselplace.com/forum/smileys/Big Smile.gif


I bet the sailboat guys aren't this bad. http://www.dieselplace.com/forum/smileys/Wink.gif


That's why I love my Dmax!

E=mc


check out this site


http://www.allisontransmission.com/documents/product/1099B.pdf (http://www.allisontransmission.com/documents/product/1099B.pdf)


we have the 1000 series trannyEdited by: Dmaxcan

I was going to use the Hoot method, but when the day rolled around it was windy and cold and my ramps don't raise the truck up enough for comfort. So, I decided to screw it and just drained and refilled (changing the spin-on, of course), using Redline Hi-Temp ATF. I'll change it on a conservative schedule, too, and someday as they're rolling me off to the home, I'll finally achieve a virtual 100% synthetic solution.

TC

I'm not planning to change over to synthetic until we start towing. But I need to replace ATF since I'm at 36K. If I flush using Hoot's method but replace with Dexron III, I won't have a marker when the new fluid is in (and all the old ATF is out), assuming their is no color difference between the old and new. Do I just use volume as the marker? That is, when the truck is running and spitting out the old ATF (while I am adding new ATF under the hood), once the volume of old ATF out reaches the volume capacity of the transmission, I stop and assume all the old ATF is out. Then just add whatever new ATF needed to fill it?

Thats the way I did it. I had an empty 2 1/2 gallon clear oil container. I put a mark about mid point. I ran the engine long enough to fill it to the mark and shut it down and refilled the trans. I am sure this is not 100% full proof but it is close enough for me. Later! Frank

Thanks, Frank....


Is the old ATF recyclable, in other words what did you do with the old ATF? I usually take my oil to Kragen here, I don't know if they accept ATF too.

biglakedmax, Great math exercise for a cold rainy day, but don't you want the NPV with something like 8% ROR? http://www.dieselplace.com/forum/smileys/Geek.gif

The local Autozone's and Checker Auto Parts here will take motor oil, gear oil, and trans oil.

It is all recyclable, even synthetic. Later! Frank

srode - don't think that didn't cross my mind. I had to stop somewhere. But now you've got me started again..what's the current discount rate...3.71? Somebody stop mehttp://www.dieselplace.com/forum/smileys/Approve.gif Edited by: biglakedmax

So if I wanted to just drain my pan and change my filter, I would need 7.4 Qts to fill it back up...correct?