Any tricks to replacing my th400 filter?
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Le Mans Master
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From: mount holly NC
2025 c3 ('74-'82) of the Year Finalist - Unmodified
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Any tricks to replacing my th400 filter?
Tuesdays job is to change the filter in my th400 transmission.
Haven't done this before and my question is does the "O" ring go on the filter first and then push it back into the transmission and put the bolts back in?
Haven't done this before and my question is does the "O" ring go on the filter first and then push it back into the transmission and put the bolts back in?
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From: Corsicana, Tx
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The oring goes on the plastic tube between the filter and the trans case. Pull it out and replace the oring. If you have two orings...put them both on. Then stick filter on and install the retainer bolt. The bolt has a shoulder on it...so don't be surprised when the filter still moves around after you tighten it.
JIM
JIM
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From: New Or-leens Loo-z-anna
Annnnnnnd.....if your car isn't "original".....buy an aftermarket transmission pan that has a "quick-drain-plug" welded into it...it makes draining the fluid much easier without the possibility of spilling.
Also......you can carefully "tap-down" the bulging area around each bolt hole (if needed) to prevent the pan from developing leaks at the gasket sealing area.
Also......you can carefully "tap-down" the bulging area around each bolt hole (if needed) to prevent the pan from developing leaks at the gasket sealing area.
Last edited by doorgunner; Dec 15, 2014 at 07:40 AM.
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St. Jude Donor '11 thru '25
Very messy job. What I've found that works nicely is a large concrete mixing tub which you can buy at Home Depot for about $6. It's large enuf to catch all the drippings.
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Le Mans Master
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From: mount holly NC
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The oring goes on the plastic tube between the filter and the trans case. Pull it out and replace the oring. If you have two orings...put them both on. Then stick filter on and install the retainer bolt. The bolt has a shoulder on it...so don't be surprised when the filter still moves around after you tighten it.
JIM
JIM
Thread Starter
Le Mans Master
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From: mount holly NC
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Overall that would be a smart thing to do, while I'm at it, but if the new kickdown switches are as bad as the new window switches then I'll wait until the old one fails.
Thread Starter
Le Mans Master
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From: mount holly NC
2025 c3 ('74-'82) of the Year Finalist - Unmodified
2019 C3 of Year Finalist (appearance mods)
Annnnnnnd.....if your car isn't "original".....buy an aftermarket transmission pan that has a "quick-drain-plug" welded into it...it makes draining the fluid much easier without the possibility of spilling.
Also......you can carefully "tap-down" the bulging area around each bolt hole (if needed) to prevent the pan from developing leaks at the gasket sealing area.
Also......you can carefully "tap-down" the bulging area around each bolt hole (if needed) to prevent the pan from developing leaks at the gasket sealing area.
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Thread Starter
Le Mans Master
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From: mount holly NC
2025 c3 ('74-'82) of the Year Finalist - Unmodified
2019 C3 of Year Finalist (appearance mods)
Didn't have time to get to HD today so I'll try to use the round bucket that I use for oil changes, and yes I have speedy dry and plenty of rags.
Thanks again to all and Happy Holidays!
Pete.
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Leave the front bolts until last. Remove the others and let it tilt downward at the rear with front bolts still in place....then gradually loosen them until it is off.
JIM
JIM
Racer
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From: Suburban Washington DC
I'm changing the fluid and filter on a later model TH400 and before removing the filter bolt noticed I could move the filter up and down a good 1/2 inch or more. Is this normal? I was thinking someone installed a replacement bolt that is too long until finding the above quote in a search.
Team Owner
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From: Crossville TN
YES!!! The real "trick" is to get the pan down without drenching yourself with tranny oil. 
Other than that, changing the filter is no big deal. Buy a good quality filter kit at NAPA [not 'the Zone' 
] and 2 gallons of ATF (synthetic if you want).
If you have a squeeze-type or crank-type siphon and tubing, put the tube down the dipstick filler hole and siphon out as much trans oil as you can. You can remove all the pan bolts if most of the oil is removed.
If you have no way to remove some of the sump oil, do it the old-fashioned-way. Remove all but the corner bolts on the tranny sump pan. Loosen corners a one end a bit, then take the other corner bolts out while you hold the pan up in place. As you lower that end of the pan, oil will POUR OUT EVERYWHERE. Have good sized drip pan under the trans if you want to stay dry.
Remove one bolt from the filter and pull the filter out. Make sure the rubber seal on the suction tube comes out with the filter.
Other than that, changing the filter is no big deal. Buy a good quality filter kit at NAPA [not 'the Zone' ] and 2 gallons of ATF (synthetic if you want). If you have a squeeze-type or crank-type siphon and tubing, put the tube down the dipstick filler hole and siphon out as much trans oil as you can. You can remove all the pan bolts if most of the oil is removed.
If you have no way to remove some of the sump oil, do it the old-fashioned-way. Remove all but the corner bolts on the tranny sump pan. Loosen corners a one end a bit, then take the other corner bolts out while you hold the pan up in place. As you lower that end of the pan, oil will POUR OUT EVERYWHERE. Have good sized drip pan under the trans if you want to stay dry.
Remove one bolt from the filter and pull the filter out. Make sure the rubber seal on the suction tube comes out with the filter.
Dr. Detroit
Joined: Mar 2012
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From: New Braunfels Texas
FYI.....during install.....I find using only a rubber trans pan gasket with no sealer is the best bet. Make sure the pan is flat around where each bolt tightens up....tap them flat if not. Use a 1/4 air ratchet with the air turned down to 40 psi to tighten them. This works perfect.....just tight enough and not overly so.
If you have the money of course I always recommend an aluminum pan.....has drain plug and easier to seal....as well as lowers trans temps.
Good luck,
Jebby
Racer
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From: Lake in the Hills IL
I'm about to tackle this one myself here w/ the TH350. Did it several years ago, and have a leaky gasket due to some stripped bolts (been dealing with the leaks for years and pretty tired of it now). Bought a helicoil kit and new trans pan. 2 reasons I bought a new pan. 1) Orig. one is more than likely warped and 2) prob. most important.. at some point I'm going to be doing this again and drain plug is going to be nice given my past experience. I could prob. hammer the orig. flat like others suggested but for the price I went with the new pan and drain hole option.
Key here is to torque to inch pounds. Some people torque to ft. lbs by mistake and that doesn't go well.
To the poster asking about the long bolt. Most likely they had a nut on the top because they stripped out the hole and used a long bolt/nut combo. I have one in mine that I know of, and at least one other jacked up hole as well that I'm going to try to fix here shortly w/ the Helicoil kit.
Key here is to torque to inch pounds. Some people torque to ft. lbs by mistake and that doesn't go well.
To the poster asking about the long bolt. Most likely they had a nut on the top because they stripped out the hole and used a long bolt/nut combo. I have one in mine that I know of, and at least one other jacked up hole as well that I'm going to try to fix here shortly w/ the Helicoil kit.
Last edited by raydog9379; Mar 29, 2017 at 09:32 PM.
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