Draining TH350 Tranny
Thread Starter
Drifting
Joined: Aug 2005
Posts: 1,430
Likes: 8
From: Hamilton NJ
Draining TH350 Tranny
Guys and Gals,
I'm getting ready to drain my '79's TH350 tranny and change the filter. Is there a drain plug on the pan/trans or do you just loosen the bolts and let all the fluid fall into a collection bin of some sort. I didn't see one when I was looking under the car. Seems kinda messy....
If I want to drain the converter (which does not have a drain plug) is there an easy way to do it? I have a small pumping system I could hook up and let go if there is an access port once the pan is removed. The pump tubing is ~3/8 inches OD.
Thanks as always,
Steve
I'm getting ready to drain my '79's TH350 tranny and change the filter. Is there a drain plug on the pan/trans or do you just loosen the bolts and let all the fluid fall into a collection bin of some sort. I didn't see one when I was looking under the car. Seems kinda messy....
If I want to drain the converter (which does not have a drain plug) is there an easy way to do it? I have a small pumping system I could hook up and let go if there is an access port once the pan is removed. The pump tubing is ~3/8 inches OD.
Thanks as always,
Steve
Racer
Joined: Mar 2005
Posts: 445
Likes: 0
From: SAN DIEGO(SANTEE) CA.
Originally Posted by Wuttin
Guys and Gals,
I'm getting ready to drain my '79's TH350 tranny and change the filter. Is there a drain plug on the pan/trans or do you just loosen the bolts and let all the fluid fall into a collection bin of some sort. I didn't see one when I was looking under the car. Seems kinda messy....
If I want to drain the converter (which does not have a drain plug) is there an easy way to do it? I have a small pumping system I could hook up and let go if there is an access port once the pan is removed. The pump tubing is ~3/8 inches OD.
Thanks as always,
Steve
I'm getting ready to drain my '79's TH350 tranny and change the filter. Is there a drain plug on the pan/trans or do you just loosen the bolts and let all the fluid fall into a collection bin of some sort. I didn't see one when I was looking under the car. Seems kinda messy....
If I want to drain the converter (which does not have a drain plug) is there an easy way to do it? I have a small pumping system I could hook up and let go if there is an access port once the pan is removed. The pump tubing is ~3/8 inches OD.
Thanks as always,
Steve
I don't think there is a way to drain the converter except thru the fill pipe, not totally sure though. Have heard that you shouldn't flush it out though cause it will cause all kinds of problems if you do.
Just drop the pan, chance or clean filter and refill.
Le Mans Master
Joined: Apr 2004
Posts: 7,106
Likes: 38
From: Newark DE
the only way to drain the torque convert is to pull the motor or drop the tranny to be able to get access to the converter to drain it.
remove the front and side bolts from the pan, loosen the rear bolts four turns and carefully pry the pan loose to let the tranny fluid drain.
once it's drained you can remove the rear bolts and pan.
clean the pan with solvent and blow it dry with compressed air.
for the filter, remove the two screws holding the strainer to the valve body. remove strainer and gasket.
clean the strainer in solvent and dry with compressed air.
reverse for reassembly with all new gaskets of course. tighten the pan to 12 ft/lbs
add 6 pints of fluid and start the motor and let it idle. move the shifter through all the gears and check the fluid level with the shifter in Park
bring the fluid level to 1/4" below the ADD mark on the tranny dipstick.
remove the front and side bolts from the pan, loosen the rear bolts four turns and carefully pry the pan loose to let the tranny fluid drain.
once it's drained you can remove the rear bolts and pan.
clean the pan with solvent and blow it dry with compressed air.
for the filter, remove the two screws holding the strainer to the valve body. remove strainer and gasket.
clean the strainer in solvent and dry with compressed air.
reverse for reassembly with all new gaskets of course. tighten the pan to 12 ft/lbs
add 6 pints of fluid and start the motor and let it idle. move the shifter through all the gears and check the fluid level with the shifter in Park
bring the fluid level to 1/4" below the ADD mark on the tranny dipstick.
Melting Slicks
Joined: Jul 2000
Posts: 2,848
Likes: 0
From: Beacon NY
Well, to quote the book Turbo Hydra-Matic 350 Handbook by Ron Sessions: (I hope I don't get busted for copyright stuff)
(page 12) "Draining the fluid from the pan, then replacing it and the filter extends the life of a transmission, but it's only part of the job. The torque converter and transmission-cooler circuit holds 6 quarts or more of dirty, broken-down fluid. To complete the fluid-changing job, you should finish draining the fluid.
Drain the Converter - Because factory converters and coolers don't have drain plugs, here is where a seemingly simple job gets involved. The ideal situation would be to remove the converter and have it thoroughly flushed, page 125. However, because a converter can't be removed with the transmission in place, it must be cleaned in place. As a result, unless you have an aftermarked converter with a drain plug, you have two ways of draining it and the cooler.
The first converter-draining method is to drill a hole in the converter housing, drain the fluid and reseal the converter with a rivet. The next method is to disconnect a cooler line and briefly run the engine to pump out the old fluid."
Well, I would be leery about drilling a hole in my converter, but the second option sounds good. I hope that helps.
(page 12) "Draining the fluid from the pan, then replacing it and the filter extends the life of a transmission, but it's only part of the job. The torque converter and transmission-cooler circuit holds 6 quarts or more of dirty, broken-down fluid. To complete the fluid-changing job, you should finish draining the fluid.
Drain the Converter - Because factory converters and coolers don't have drain plugs, here is where a seemingly simple job gets involved. The ideal situation would be to remove the converter and have it thoroughly flushed, page 125. However, because a converter can't be removed with the transmission in place, it must be cleaned in place. As a result, unless you have an aftermarked converter with a drain plug, you have two ways of draining it and the cooler.
The first converter-draining method is to drill a hole in the converter housing, drain the fluid and reseal the converter with a rivet. The next method is to disconnect a cooler line and briefly run the engine to pump out the old fluid."
Well, I would be leery about drilling a hole in my converter, but the second option sounds good. I hope that helps.
Last edited by Victor; Apr 19, 2006 at 02:12 PM.
