Advice on Transmission Fluid Change for 1980 C10

[Grit dog]

If it’s operating fine then absolutely change it. Sounds like a good truck if it’s never been apart and still is truckin.

If you don’t pump it out the cooler lines to get the majority of old out, I’d get a pan with a drain plug and change it about 4x depending how much comes out. That’ll effectively replace about 90% of it.

 

[Grit dog]

If it’s operating fine then absolutely change it. Sounds like a good truck if it’s never been apart and still is truckin.

If you don’t pump it out the cooler lines to get the majority of old out, I’d get a pan with a drain plug and change it about 4x depending how much comes out. That’ll effectively replace about 90% of it.

Unless you’re lucky and there’s a drain plug in the tq converter but it’s not likely.

 

[Turbo4whl]

Unless you’re lucky and there’s a drain plug in the tq converter but it’s not likely.

The only factory torque converter that had a drain plug in them were old Fords. (I've only ever seviced trucks, don't know about cars.) Aftermarket converters may have a plug, but the OP stated he believed the trans was not apart.

 

[AlabamaDan]

Thoughts on this:

https://www.oreillyauto.com/detail/...?q=premium+automatic+transmission+fluid&pos=0

 

[Camar068]

Dex III is the same as Dex/Merc from what I've read.

 

[AlabamaDan]

Added more fluid and it drives great! Shifts smooth and all is well. Now, could someone please help me ID this trans from the pan? It's a leaking mess under there btw.

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[DoubleDingo]

Look at post 2 of this thread

 

[Dmack]

TH350, aka turbo 350

 

[75gmck25]

Stock TH350 is a very durable, reliable transmission. Many sources of aftermarket parts if you want to build it to be even stronger.