Tranny fluid capacity, and recommendations? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

*Mister-B* · 10-21-2012, 09:34 PM

I have a '69 with the TH400 automatic transmission. If I drain and fill the tranny fluid, how much fluid should I purchase? The parts store says it call for Dexron III. Is that correct?

What's a good tranny fluid? Anybody run synthetic with good results?
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**jocko** · 10-21-2012, 09:39 PM

According to owner's manual, TH400 "TOTAL" is 9.5 quarts but "REFILL" is 7.5 pints. Remember that just draning via the pan still leaves most in the torque converter. Also, add 1.75 quart if you have a trans cooler.
I'd stick Dexron III for the fluid, but that's just me.

*Mister-B* · 10-21-2012, 10:08 PM

Quote:

Originally Posted by jocko

According to owner's manual, TH400 "TOTAL" is 9.5 quarts but "REFILL" is 7.5 pints. Remember that just draning via the pan still leaves most in the torque converter. Also, add 1.75 quart if you have a trans cooler.
I'd stick Dexron III for the fluid, but that's just me.

Wow, so the transmission holds more fluid than a 350 V8?
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**FirstOwner69** · 10-21-2012, 11:11 PM

There's some interesting reading in this thread http://www.dieselplace.com/forum/sho...d.php?t=420656 (it's an extremely long thread) from www.thedieselplace.com forum regarding transmission fluid for the Allison trans used with the Duramax. However, there's much more information about transmission fluid in general. It sounds like there is no longer any real Dex III , and based on comments about Dex VI, I'd be hesitant about using it in a TH350 or TH400. I just changed the fluid in the Allison in my 2006 from Dex VI to Allison TranSynd and am thinking about using it in my TH400 when I get set to fire up the truck following my restoration. This thread suggests TranSynd for all transmissions.

I don't mean to hijack this thread. I just think this info may be helpful. Are there any experts out there who care to comment?

10-21-2012, 09:34 PM	#1
Mister-B Account Suspended Join Date: Oct 2012 Location: Salt Lake City, Utah Posts: 3,331	Tranny fluid capacity, and recommendations? I have a '69 with the TH400 automatic transmission. If I drain and fill the tranny fluid, how much fluid should I purchase? The parts store says it call for Dexron III. Is that correct? What's a good tranny fluid? Anybody run synthetic with good results? Posted via Mobile Device

10-21-2012, 09:39 PM	#2
jocko Senior Member Join Date: Oct 2009 Location: Godley, TX Posts: 17,976	Re: Tranny fluid capacity, and recommendations? According to owner's manual, TH400 "TOTAL" is 9.5 quarts but "REFILL" is 7.5 pints. Remember that just draning via the pan still leaves most in the torque converter. Also, add 1.75 quart if you have a trans cooler. I'd stick Dexron III for the fluid, but that's just me.

10-21-2012, 11:11 PM	#4
FirstOwner69 Senior Member Join Date: May 2010 Location: Wisconsin & Arizona Posts: 4,847	Re: Tranny fluid capacity, and recommendations? There's some interesting reading in this thread http://www.dieselplace.com/forum/sho...d.php?t=420656 (it's an extremely long thread) from www.thedieselplace.com forum regarding transmission fluid for the Allison trans used with the Duramax. However, there's much more information about transmission fluid in general. It sounds like there is no longer any real Dex III , and based on comments about Dex VI, I'd be hesitant about using it in a TH350 or TH400. I just changed the fluid in the Allison in my 2006 from Dex VI to Allison TranSynd and am thinking about using it in my TH400 when I get set to fire up the truck following my restoration. This thread suggests TranSynd for all transmissions. I don't mean to hijack this thread. I just think this info may be helpful. Are there any experts out there who care to comment?



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