Bolting a Transmission Pan Back in Place

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Introduction: Bolting a Transmission Pan Back in Place

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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21 Comments

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.

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.

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.

I just hope my car will last another 30,000 miles.

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.