careful1

Typically how do you check to determine if the pan is warped? I put the gasket on and layed the pan, gasket down, and it touches the metal tabs except one

dr bob

The gasket surface is what needs to be flat. On your known-flat work surface, put the pan down without the gasket and see where the gaps are. With the gasket installed, use strips of paper to see where the gap might be uneven. Just pull the paper strips out one by one, and you'll find the high spots.

Be sure to install a new o-ring for the reservoir seal too.

careful1

Dr. Bob,Without the gasket the metal bolt tabs keep the mating surface well off of the flat surface. I can't tell because the tabs hold it above my table top and with the gasket on parts of the gasket that look like they are flat may not be pushed up tight against the pan evenly. Thanks, Doug.

Captain_Slow

Next time I have the pan off I'm going to trace the gasket on thick MDF, cut it on a band saw, then lay the pan on that MDF with the metal tabs hanging off the edges. I can't think of any other "lay it on a flat surface" way to do it.

Just as important is what to do if you find it is warped. Well...if it's leaking, may as well try what many techs routinely do with steel pans - try to tap the areas flat. Best I could find on the technique is put an appropriately sized carriage bolt (round head) on hole in the bent tabs and lightly tap with hammer, check for flatness often. Odds of success may not be favorable, but worth a try.

dr bob

Ultimately your goal is to have even gasket pressure all the way around the sump. Try the paper-strips test with the gasket in place to see where there might be looser spots/gaps. The torque on the sump bolts is very small, much less than what's used on those little drain plug bolts for instance. I don't have WSM's or torque specs handy, but do know that you'll need a good lbs/inch torque wrench to get an accurate torque on the bolts. Clean bolt and case threads of course. For the paper-strip test, you might decide to put a weight on the middle of the upside-down pan to make the friction differences more apparent.

Wait a sec, I have Rob Edwards' amazingly-useful bolt torque spreadsheet here on the tablet. Stop reading for a minute while I start the tablet and find the chart... Hmmm, chart doesn't have auto transmission values in it. Guess we need to start a "buy Rob an S4 Auto Fund" since all he has are manual-transmission cars...

dr bob

Good Idea, but... Warped pans happen for several reasons, most common seems to be from hamfisted wrench-handlers. Next is accident/grounding damage, followed by floor-jack pressures. There are too often combinations of factors, where a leak caused by a pan bent during other episodes is compounded when a wrench is used to try to draw the pan straight again while attached to the transmission with gasket and fluid above it. Like metal bodywork repairs, the only safe way to undo warping from bolt-too-tight is to apply pressure exactly opposite the original damaging pressure, until the pan is un-warped.

So follow your method with the cut-out piece by attaching it to a couple larger layers of flat something, like the same MDF. Bolt the sump through the larger pieces so the gasket surface is in contact with the cutout piece. Use additional nuts and washers between the sump bolt ear and the fixture so you can push a warped section back up while holding the other ears in place. It --might-- work.

Our regular vendors sell replacement transmission pans. The last one I bought for a guest car was under $50, but that was a lot of months and undoubtedly a similar number of dollars ago. The basic sump is shared with several M-B models that use the same transmission internals, but has the tube for the fluid reservoir brazed on, so no direct interchange. Careless heating while brazing will warp the sump...

Rob Edwards

6 ft lbs.

Normally I'd LOL at your Rogerbox tinfoil turkey roaster drain pan sealing problems (5-speeds have the cover on the top- no leaks...) , except that it's not at all funny what a new one costs these days:

http://shop.928intl.com/4sp-At-Trans...722-270-091-2/

Any effort to flatten a bent/overtorqued/mushroomed mounting hole flange is certainly worth attempting given the cost of the alternative, and careful torque is essential to prevent tweaking the pan. If it still leaks with a correctly installed and torqued pan and gasket, then the pan needs more flattening, or replacement.

careful1

Thanks guys, I'm changing all the gaskets and O-rings involved in the trans. even got the rubber cooling lines kit that Roger sells. I'm trying to make sure I stop the flow of trans. fluid that I keep getting all over the floor. So ,If you notice the stock prices of the transmission fluid manufacturers fall ...that will be me fixing those freaking leaks .

Rob Edwards

At 850 freaking dollars for a new factory pan, in the era of waterjet cutters and dxf files there ought to be some margin for someone to come up with an aftermarket pan replacement. The curved pipe and its fitting to the reservoir is a bit of a complication, but they could be harvested off dead pans to get started and then from customer pans coming in as a core...

GregBBRD

Those "ears" on the pan bend out and need to be hammered back into position, in order to get a good seal. If the actual area where the gasket sits is flat, you have a good chance of the pan sealing properly.

I "tap" on the tabs until they fit nicely (tight) on the transmission.

BTW....I used to think that these tabs got bent by people who worked on the vehicles after they left the factory and over tightened the pans. While I don't doubt this is partially true, when I bought all of those brand new factory transmissions, it was really interesting to note that the tabs were bent out on those, also.

The tabs are just flimsy.

As a final note, I do find pans that do require replacement. The tabs get softer as they get bent and repaired several times. They will get to the point where they simply bend so easily that the gasket will not get tight enough to seal. That's the time for a different (perhaps used) pan. (The pans used to only be a couple of hundred dollars, and while not cheap, that certainly was not out of touch for people. The current price for a new pan seems silly.)

Captain_Slow

Greg/Rob/Dr. Bob -
Thanks for posting a lot of good info and ideas. Sure would be nice if Rob's idea for an alternative could happen soon. 928 Intl already offers a very nice CSF radiator at a better price point than a new "turkey roaster" trans pan. Think about this a minute....it is silly.

docmirror

Get a bag of sand, lay it on the level ground and break open the side of the bag, leave the sand in the bag. Use a level across the mating surface and smoosh the pan down into the sand, keeping level. Cross the level 90deg and check that way too.

Fill the pan with water to just below the mating surface and do a second more precise leveling with a dead blow mallet or sliding it side to side gently. Fill slowly with water by wicking it down a wooden dowel/pencil in the center until the water is at the rim of the mating surface.

You will be able to fill the water slightly higher than the level mating surface. This is called the meniscus and it's a function of the molecular bond of water vs the Al of the pan. Lay down and sight across the meniscus side to side, and end to end with good light, you will see any low spots clearly. Accurate to within ~ .002" or so.

dr bob

Starting point is to get the cost for a new M-B pan to use with a new reservoir tube. IIRC, Roger deals in new M-B parts as a sideline. The 1232700412 sump itself is under $200 list price from M-B per an online dealer parts catalog. Then buy the right tubing, put a bend in it, fixture to support the tube for brazing, drill a hole, braze, repaint. Might make an interesting little side business, except that the sales volume of these pans is really tiny.

Greg, were the tabs on your NOS transmissions' sumps bent from having the weight of the trans sitting on the sump while in storage?

Meanwhile, at $850, I need to add a padlock to the bolts holding mine to the bottom of my transmission. Easy to see how a good car is worth more in parts than whole. Or, can I negotiate $850 off the price of every for-sale car that has a sump leak?

GregBBRD

Notes above, in blue.

soontobered84

Note to self (a hamfisted wrench-handler): DO NOT overtighten the bolts holding transmission pan in place!!