SAE20 Motor oil for Trans. fluid????

HP JUNKEY

Dragway Regular
Oct 30, 2008
1,093
0
36
Buffalo.NY
I went to our local Advance Auto yesterday to grab some Type F, and the counter guy asks me what I was running it in, so I tell him a Street/Strip Turbo 350...... He says that him and his buddies just started using straight 20 weight motor oil in their transmissions :shock: :shock: I'm like, "WHAT"??? He says that on a FRESH trans the motor oil runs 25 to 35 degrees cooler and holds up better then trans fluid...........I believe he uses it but I am skeptical about it.....Any thoughts????
 

10secBu

MalibuRacing Junkie
May 21, 2003
4,284
0
36
Westminster, MD
Can't say I've ever heard of using motor oil in a transmission. I would question if the oil has the correct additive package for a hydraulic clutch transmission.

Now some cars will use a hydraulic oil in place of transmission fluid, but have not heard of motor oil.
 

LS6 Tommy

MalibuRacing Junkie
May 15, 2004
15,848
0
36
North Jersey
Umm, NO. ATF is NOT motor oil... Trans pump & converter stresses will kill motor oil. Some imports use motor oil in their manual trannies, but that's a different thing altogether.

Rule #1- don't listen to the idiots at the parts store. They're NOT technicians... (Usually)

Tommy
 
I've encountered several racers that have claimed to use Mobil 1 5W-20 synthetic oil in their transmissions, but have no idea what the long-term results were. That being said, engine oil does not have the proper friction modifiers and anti-foaming agents for use in an automatic transmission. I do not foresee the frictions and band(s) providing very good longevity or durability if you were to attempt to use engine oil in an automatic.

Also, as LS6 Tommy brought up, engine oil is not going to be very durable when encountering the sometimes extreme high temperatures that can be generated in the torque converter, especially if you are using a torque converter with a high stall speed.

If you're looking for something better than your average parts store ATF then I suggest using either Lucas Sure Shift or Lucas Marine ATF. We use these two products exclusively in everything we build. These fluids provide outstanding durability, longevity, and heat management properties. We use the Sure Shift in all street, street/strip, towing, and off-road applications. We use the Marine ATF in most extreme high horsepower applications (Sure Shift still works well in these also), although the Marine ATF can easily be used in lower-power applications as well.

Three good rules of thumb to follow when it comes to this type of thing:

1.) If it ain't broke, don't fix it.
2.) Don't try to re-invent the wheel.
3.) Anytime the conversation turns to "me and my buddies all do this...", stop listening. That is an official conversational red flag that the b.s. is really going to get thick if you allow the conversation to continue. ;)
 

HP JUNKEY

Dragway Regular
Oct 30, 2008
1,093
0
36
Buffalo.NY
I've encountered several racers that have claimed to use Mobil 1 5W-20 synthetic oil in their transmissions, but have no idea what the long-term results were. That being said, engine oil does not have the proper friction modifiers and anti-foaming agents for use in an automatic transmission. I do not foresee the frictions and band(s) providing very good longevity or durability if you were to attempt to use engine oil in an automatic.

Also, as LS6 Tommy brought up, engine oil is not going to be very durable when encountering the sometimes extreme high temperatures that can be generated in the torque converter, especially if you are using a torque converter with a high stall speed.

If you're looking for something better than your average parts store ATF then I suggest using either Lucas Sure Shift or Lucas Marine ATF. We use these two products exclusively in everything we build. These fluids provide outstanding durability, longevity, and heat management properties. We use the Sure Shift in all street, street/strip, towing, and off-road applications. We use the Marine ATF in most extreme high horsepower applications (Sure Shift still works well in these also), although the Marine ATF can easily be used in lower-power applications as well.

Three good rules of thumb to follow when it comes to this type of thing:

1.) If it ain't broke, don't fix it.
2.) Don't try to re-invent the wheel.
3.) Anytime the conversation turns to "me and my buddies all do this...", stop listening. That is an official conversational red flag that the b.s. is really going to get thick if you allow the conversation to continue. ;)
LOL,,,,I have no intentions on "trying" motor oil in either of our transmissions :lol: you always hear a lot of weird things coming from all walks of life, some strange things are actually true or have some merit :lol:...

If I were to switch from the type F to the Lucas trans fluid, will the Lucas "mix" o.k. with what is left over in the convertor?
 
HP JUNKEY said:
I've encountered several racers that have claimed to use Mobil 1 5W-20 synthetic oil in their transmissions, but have no idea what the long-term results were. That being said, engine oil does not have the proper friction modifiers and anti-foaming agents for use in an automatic transmission. I do not foresee the frictions and band(s) providing very good longevity or durability if you were to attempt to use engine oil in an automatic.

Also, as LS6 Tommy brought up, engine oil is not going to be very durable when encountering the sometimes extreme high temperatures that can be generated in the torque converter, especially if you are using a torque converter with a high stall speed.

If you're looking for something better than your average parts store ATF then I suggest using either Lucas Sure Shift or Lucas Marine ATF. We use these two products exclusively in everything we build. These fluids provide outstanding durability, longevity, and heat management properties. We use the Sure Shift in all street, street/strip, towing, and off-road applications. We use the Marine ATF in most extreme high horsepower applications (Sure Shift still works well in these also), although the Marine ATF can easily be used in lower-power applications as well.

Three good rules of thumb to follow when it comes to this type of thing:

1.) If it ain't broke, don't fix it.
2.) Don't try to re-invent the wheel.
3.) Anytime the conversation turns to "me and my buddies all do this...", stop listening. That is an official conversational red flag that the b.s. is really going to get thick if you allow the conversation to continue. ;)
LOL,,,,I have no intentions on "trying" motor oil in either of our transmissions :lol: you always hear a lot of weird things coming from all walks of life, some strange things are actually true or have some merit :lol:...

If I were to switch from the type F to the Lucas trans fluid, will the Lucas "mix" o.k. with what is left over in the convertor?
Yes sir, either fluid will blend with Type F without any issues. The Sure Shift actually says on the label "not for use with Type F applications", but we have ran it blended upwards of 50/50 with outstanding results while experimenting with various ATF types, formulas, and blends in our own racing program.
 

TexasT

Member
Feb 18, 2013
9
0
0
I would not try motor oil but I do use hydraulic oil. Cheaper than trans fluid but somewhat hard to see on the dipstick.

 

malibu795

Pro Stocker
Apr 17, 2005
1,479
0
36
spgfd ohio
while I have used HYD in autos yet....
I have mess with PS systems in a hyd boost application in heavy towing applications...
PS is ~7w
ATF is ~10w
hyd is ~15W

HYD fluid is usually designed to handle 200-250* at 3000-4000psi without fading..

avg performance trans maxed out under 300psi though some all our race will push 500psi..

one thing to keep in mind, thicker the fluid WILL lower stall/coupling of the TC, thicker fluid is harder to shear
 

TexasT

Member
Feb 18, 2013
9
0
0
shoedoos said:
Other than price, what characteristics make the tractor fluid your choice?
I was told to try the John Deere HyGuard but I wasn't into trying to source it. I found this in a five gallon bucket at the autozone for about $55. Seemed to be compatible by the specs on the bucket. Ive been using it for several years. Seems to work good.

So, to answer the question, price and the ability to get it local. It was an experiment and I like my results.
 

LS6 Tommy

MalibuRacing Junkie
May 15, 2004
15,848
0
36
North Jersey
Doober said:
Interesting to read...

My Fiero uses 5w-20 in the 282 Getrag, says so right on the dipstick plug... almost 190k on the car (probably trans too?) and it still shifts just fine.
Many manual transmissions use motor oil. The OP was asking about using it in an automatic...

Tommy
 

Vilanus

Daily Driver
Jun 2, 2019
21
1
3
Canada
Its very hard to believe that motor oil would be better then tansmission fluid specifically engineered by manufacturers and oil companys with billions in R&D

5$ a quart for dexron VI synthetic isnt that expensive