Bolting a Transmission Pan Back in Place





Introduction: Bolting a Transmission Pan Back in Place

About: I miss the days when magazines like Popular Mechanics had all sorts of DIY projects for making and repairing just about everything. I am enjoying posting things I have learned and done since I got my first ...

I change the fluid and filter in my automatic transmission every 30,000 miles. The pan gasket is rubber. The recommendation is apply grease to the pan under the gasket. This is supposed to hold the gasket in place. Usually it does, although the process always makes me nervous about the gasket moving and causing a leak. It finally happened. The gasket slipped out of place somehow just about as you see it here. I lost several quarts of oil on the garage floor.

Step 1: A Resolution of the Problem

Cut some card stock about 1 x 1 1/2 inches. Make as many as you have transmission pan bolts.

Step 2: Make a Sandwich With Two Pieces of Wood

Use two pieces of scrap wood to make a sandwich with the card stock.

Step 3: Clamp the Sandwich

You will be drilling a hole through the card stock. That means drilling through the wood, too. The wood sandwich gives you the best chance for a clean hole in the card stock.

Step 4: Drill

Select a bit a little smaller than the transmission pan bolts. Drill through the top piece of wood and the card stock. You will probably drill into some of the bottom piece of wood, too.

Step 5: Slice With a Scissors

Slice from the edge of the card stock to the hole with a scissors.

Step 6: Use the Card Stock to Retain the Bolts

Insert the bolts through the pan holes and the gasket holes. Slip a piece of card stock over the bolts to hold them in place.

If I were to do it again, I would push the bolts only half of their length through the card stock retainers. When I was positioning the pan, some of the bolts pushed out as I threaded their neighbor into the transmission. Still, enough of the gasket was securely in its proper place that I had no problems from a bolt or two dropping out.

Step 7: Start Bolting the Pan to the Transmission

The card stock keeps the bolts in place, which keeps the gasket in place. When starting the bolts into the transmission case threads, try to keep the card stock from rotating inside the transmission. When all of the bolts are started, pull the card stock pieces off of the bolts and throw them into a waste container. Double check to be sure the gasket is still in place. Work your way around the bolts and tighten each two or three times in a rotation to take up any compression of the gasket.



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    Thank you. I could have saved myself a few problems over the years had I thought of it earlier. I hope it is a help for you.

    The cardstock would be great to help hold the gasket in place while the "brush-on" sealant sticks the gasket to the pan. After that I'd remove the bolts, wash the bolts in solvent, and grease the top of the gasket before installing I have a drainplug on my pan and I drain out about a quart and a half every oil change. I still have to drop the pan for the filter screen once every two years, but even that is far easier when you can drain the fluid first. I'd advice to never, ever flush a tranny. Regular replacement of a small amount of fluid is best. one of these days one of those upstart car companies is going to overcome the barriers of entry into the US marketplace, and show the USA workfare car companies how to add a simple magnetic drainplug and an external spin-on tranny filter to speed up periodic maintenance. Of course, with a simple modification like that, and a true filter rather than a screen, the slush-box will likely live forever.

    1 reply

    The purpose of the cardstock is to hold the bolts in order to keep the gasket in place. I have had bolts fall out and believe a gasket could move, even with a sealant. The maker of the gasket recommended not using any gasket sealant, other than smearing some grease on the pan under the gasket. No gasket sealant, like Permatex #2, makes for very easy preparation for installation after draining and replacement of the filter. I have seen kits for adding a drain plug to a transmission pan.

    What ever happened to just brushing on some gasket adhesive? Also I once used some "gasket in a can" stuff that comes out like EZ cheese spread and the tranny didn't leak a drop. I don't know why more cars don't just have a drain plug like the oil pan does, like my Honda.

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    My memory says gasket adhesives got a bit of a bad name in the early 1980's when General Motors used them in place of gaskets on their engines, and the engines began to leak oil after a very few years of service. We had a neighbor faced with either an expensive overhaul or selling her GM car at a sacrifice price because it leaked oil badly. It is recommended that you change the filter as well as the transmission fluid. A drain plug would make draining the fluid easier, but the pan would still need to be removed to change the filter.

    Would that be the white Toyota wagon on your web page, the one with the decorative cardboard and aluminum foil? Toyotas have a reptutation for going a couple of hundred thousand miles.

    Nope, that was just a random picture i found YEARS ago. And i should know, my Toyota has over 304 thousand miles on it.

    Our van has 53k kilometers on it and the only repair yet wasa simple brake pedal switch to turn the brake lights on.There may be more I don't remember.

    53K kilometers is about 31K miles. A friend was well acquainted with a transmission repairman. The guy who ran the transmission shop said if people would just change the filter and transmission fluid in their vehicles every 30K miles he would be out of business. It is good preventive maintenance.

    Fantastic fix, it's this sort of simplicity that the world needs.
    I once had "work experience" in a LandRover garage: they'd spent a morning completely rebuilding an engine (broken piston-ring) and then realised they'd forgotten a gasket. Their solution was to lean very heavily on it with big screwdrivers and try to push the gasket in the gap............(sigh)


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    It is good to know even the professionals have some of the problems we amateurs experience. Thank you for the comment.

    This is a great idea, though I worry that you might leave some card stock behind to gum up your tranny. Maybe you could use something like a hairpin instead of the paper. Anyway thanks for the idea. I'm sure I've lost several hours of my life to gaskets that wiggled out of position.

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    The card stock is heavy enough that it does not tear easily. The scissors cut from the edge to the hole allows the card stock pieces to slip off of the bolts quite easily. Plus, you can easily examine the card stock pieces to see if they come out intact. I think the card stock stays in place better than a hairpin would, but, give it a try. Thanks for your comment.

    the first & last time i opened a tranny all the parts fell out : \

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    Hmmm? Might there have been another problem? Sorry to hear about your misfortune.

    Nice example of KISS (keep it simple and stupid) This will be usefull in more places.

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    Thank you. Yes, it should be useful elsewhere, too. NachoMahma mentioned gaskets on rocker arm covers over the valve train.

    . I've been working on cars and reading car mags for 35 years and have never seen or heard of this most excellent idea. This will come in handy for valve covers, &c;, too.