1994 sierra transmission/radiator lines?

[Alex Vietmeier]

afternoon gents,
I have to replace the rad on my 1994 Sierra.. on the passenger side of the rad, there’s two lines that I believe are related to my transmission. I’m trying to find parts numbers for these hoses so I can replace them in my new rad but I’m having a hard time coming up with the numbers.

Also where do these lines go to?,

Does 1 come off tranny and into rad,
1 from rad into tranny cooler, then a 3rd one go from tranny cooler back to tranny?

Thanks for the help lads

 

[JLG88]

If you have an external transmission cooler, just Hook both lines straight to it. Hot coolant isn’t good to cool hot transmission fluid.

 

[someotherguy]

If you have an external transmission cooler, just Hook both lines straight to it. Hot coolant isn’t good to cool hot transmission fluid.

With an aux cooler it is best to plumb it in along with the one built into the radiator.

Have you studied engine and transmission operating temperatures? The truck's cooling system keeps the engine coolant at around 195F-200F (assuming correct thermostat and operation of the system.) Coincidentally, that's also a pretty good operating temperature for the transmission. A little cooler than that is fine, much hotter than that is not good. However you can have it TOO cool, and running the trans fluid through a cooler in the radiator helps it get up to correct temperature and stay fairly uniform.

If you run the transmission with only the air-to-air cooler of an aux cooler, it's entirely possible for it to get too hot, depending on size, efficiency, and placement of the cooler.

Richard

 

[someotherguy]

afternoon gents,
I have to replace the rad on my 1994 Sierra.. on the passenger side of the rad, there’s two lines that I believe are related to my transmission. I’m trying to find parts numbers for these hoses so I can replace them in my new rad but I’m having a hard time coming up with the numbers.

Also where do these lines go to?,

Does 1 come off tranny and into rad,
1 from rad into tranny cooler, then a 3rd one go from tranny cooler back to tranny?

Thanks for the help lads

Hoses? The transmission cooling lines are metal all the way from the transmission case to the cooler built into the radiator. You may be looking at the engine oil cooler lines, which are a combination of metal line and rubber hose. Engine oil cooler is on one side of the radiator tank, transmission cooler is on the other side.

Richard