trans fluid level

Ron Gusack · 06-10-2012, 11:42 AM

I read a post on another site where a guy is having problems with his TH400 spitting trans fluid out the vent. A few of the responses are to run 1 quart low and that all performance trans are run this way. I have a 400 and have never run it a quart low and never had fluid pushed out. Is it a common practice to run a 400 one quart low?

ss3011 · 06-10-2012, 01:20 PM

If you have a factory shallow car pan, then the full hot mark, on the dipstick is even with the pan gasket. The full hot mark on the factory deep truck pan is about 1 inch below the gasket. If you use a car dipstick, and tube, but have a truck deep pan, then effectively you are overfilling the trans, which leads to oil out the vent. The factory sets oil level, so that hot, the oil level will not reach the spinning parts in the barrel. If the oil gets up that high it will froath up , like a milk shake, which raises the level even further. The result is the breather system cannot handle the extra mist and will leak it out.

Ron Gusack · 06-10-2012, 06:33 PM

Thanks for that information. How does one identify a truck /car dipstick or tube?

06-10-2012, 11:42 AM	#1
Ron Gusack Member Join Date: Feb 2009 Posts: 243 Likes: 1 Liked 7 Times in 6 Posts	trans fluid level I read a post on another site where a guy is having problems with his TH400 spitting trans fluid out the vent. A few of the responses are to run 1 quart low and that all performance trans are run this way. I have a 400 and have never run it a quart low and never had fluid pushed out. Is it a common practice to run a 400 one quart low?

06-10-2012, 01:20 PM	#2
ss3011 Senior Member Join Date: Feb 2002 Location: Southeast Michigan Posts: 889 Likes: 63 Liked 225 Times in 104 Posts	Re: trans fluid level If you have a factory shallow car pan, then the full hot mark, on the dipstick is even with the pan gasket. The full hot mark on the factory deep truck pan is about 1 inch below the gasket. If you use a car dipstick, and tube, but have a truck deep pan, then effectively you are overfilling the trans, which leads to oil out the vent. The factory sets oil level, so that hot, the oil level will not reach the spinning parts in the barrel. If the oil gets up that high it will froath up , like a milk shake, which raises the level even further. The result is the breather system cannot handle the extra mist and will leak it out.

06-10-2012, 06:33 PM	#3
Ron Gusack Member Join Date: Feb 2009 Posts: 243 Likes: 1 Liked 7 Times in 6 Posts	Re: trans fluid level Thanks for that information. How does one identify a truck /car dipstick or tube? Last edited by Ron Gusack; 06-10-2012 at 06:38 PM.