I am planning on changing the fluids in my transfer case,transmission, front diff,and rear diff. should I put synthetic in it and what kind? I tow a 7000k boat and have been changing the tran fluid every 15k miles, and it is now time to do it again. will I get better milage after I put synthetic everywhere because I shure need it..I am getting 10mph around town and 13-15 hwy, 10 towing the boat, with summer here we are planning on traveling the east coast looking for great fishing spots around the coast and the milage is killing me..

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1999 SD F250, V10,4x4,3.73gears, all the options, bright red,gibson duel exhaust

 

?????

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1999 SD F250, V10,4x4,3.73gears, all the options, bright red,gibson duel exhaust

 

I doubt you will see any change in mileage (certainly the extra cost of the oil will never pay for itself) but the synthetics will give you more protection when towing.

Ian

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99 Expedition EB
5.4l, 4x4, 4.10 LS
WMS Tube, Bassani Cat Back Exhaust, Superchip Flipchip, PIAA Superwhites

 

Actually synthetics will pay for themselves if you use the right kind.

Amsoil synthetic ATF is recommended at 3 times the drain interval compared to conventional ATF. So that equals less change outs, saves time and money.

Amsoil has a short term temp rating of 375 degrees. Once your conventional fluid overheats you run the risk of killing your transmission.
Even a 1 time over heat Amsoil will pay for itself 100 fold, since a transmission rebuild is over $1000 and total cost of the fluid might be $50 or so.

Synthetics carry heat away from internal parts better because of their laminar flow, less heat equals less wear.

Synthetics fluids reduce friction which reduces heat and wear! Less heat and wear equals longer equipment life.

I don't care what brand of fluid you use, but just make it synthetic!

Here is information about Amsoil and Mobil 1 ATF
http://www.amsoil.com/products/atf.html

http://www.mobil1.com/mobil1_racing/...atf/index.html

If you do change to synthetic make sure you do a 100% change out to get all of the old fluid out!

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actually, from fluids, turbulent flows yield much higher heat transfer rates than laminar flows, because the velocity boundary layer is much fuller in turbulent flow which results in a much higher temperature gradient between the surface and freestream...

of course, i've really only studied airflows, so oil may be completely different

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2001 F-150 XL SWB
4.2L 5-spd, 3.55

University of Texas - Aerospace Engineering Class of 2001

 

evan

I used Amsoil 75w140 in the rear, 75w90 in the front diff. ATF in the tcase and my 5sp tranny.

Rear on my 3.55 takes just shy of 3 litres/quarts
Front about 2.2 litres
Tcase - 2.5 litres
manual tranny - 4 litres.

hth
Bambino

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1999 reg cab/short box/ORP/Silver on Dk Graphite - 3.55; 4.6l 5sp; Factory Tonneau; 40 chan CB/Maxrad Antenna; Kicker amp'd sub tubes; Rockford Fosgate components up front; Custom Exhaust; Mobil 1 5w30/Motorcraft FL820s; Amsoil Series 2k in the driveline.

 

This is true, but more work is required to pump a turbulent flow compared to a laminar flow due to greater wall shear stresses on the fluid. An interesting problem! I went with Amsoil ATF and don't plan on changing the fluid for at least 50K. The truth is a quality ATF, a good cooler, and a shift kit can make a trans last 200k miles. Most transmissions fail due to neglect i.e. lack of regular fluid changes, no cooler, HEAT etc

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