Modded Mustang Forums banner

1 - 12 of 12 Posts

·
Registered
Joined
·
58 Posts
Discussion Starter · #1 ·
My mechanic who is doing my transmission swap from auto to manual suggested I use 30 weight non detergent motor oil and syncromesh in my t45....anyone heard of this or done this?
 

·
Registered
Joined
·
2,223 Posts
Never heard of doing that. I just use regular ol' dex/merc in mine and it's butter.
 

·
US Air Force (retired)
Joined
·
13,542 Posts
Never heard of it. Owners manual says to use automatic transmission fluid.
 

·
Registered
Joined
·
849 Posts
That's some hard core way way old school tech. The motor's clearances are not designed for that AT ALL, and it won't work out well.

Here's a basic primer on motor oil weights - 5W20 means that when cold, the oil flows like 5 weight oil. This is important, as it allows the oil to flow to critical parts of the engine faster. 20 means it flows like 20 weight when warm. This is also important as it offers a slightly better barrier of protection. When hot, it will flow about the same as it did when it was cold.

Straight 30 will flow like 30 when it's cold, and 30 when it's hot - meaning it can't get to the tight clearances of modern engines with any urgency, leading to more start up wear/tear and no benefit.

No offense to the guy, he may be knowledgeable, but not about this.
 

·
Registered
Joined
·
849 Posts
Mixing 30W oil and synchromesh in a trans? Froth heaven and quick failure is what it seems like to me.
 

·
Registered
Joined
·
2,936 Posts
Motor oil's additive package, designed for plain bearings, is all wrong for the anti-friction bearings in a transmission...
 

·
Procrastinator
Joined
·
4,558 Posts
we use atf because its cheaper for ford to just use one oil for everything. I have read that some motor oils are better for a transmission than the atf thrown in there. There are additives in motor oil that are better for a manual transmission than atf. I think one of the oils to use is high milage mobile one, maybe start googling that. Good luck.
 

·
Registered
Joined
·
2,936 Posts
Nonsense--Tremec recommends ATF for both the T-45 and T3650--and they have no horse in Ford's race. ATF is engineered to be the best for ball bearings and clutches (which synchro rings are), motor oil is not...
 

·
Registered
Joined
·
808 Posts
CLassic case of mechanic seeing how stupid the customer is. Watch him.
 
1 - 12 of 12 Posts
Top