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Transmission pan replacement with Chrysler ATF RTV. How to handle drips?

44K views 39 replies 22 participants last post by  crymar 
#1 ·
I've replaced the transmission pan two times already. The first time the generic gasket had holes that were misaligned and it wrinkled and leaked. Badly.

So I bought some fresh black RTV, cleaned everything up really well, applied the RTV to the pan, let skin over for 15 minutes, cleaned off the sealing face as well as I could, then applied the pan without moving it around, tightened the pan bolts up to around 2-3 ft lbs, let cure for 2 hours, then finished torquing to the specified torque. This behavior has always worked for me when sealing with RTV. But I still have a very slow drippy leak, maybe 1-2 teaspoons per day.

I think that the problem was that I let the tranny drip for "only" 4 hours before reinstalling the pan. But it was still dripping slowly. I wiped up inside as far as I could and hurried to get the pan on, but I'm sure that a tiny bit of ATF dripped down in the 10 seconds it took me to mount the pan.

So, I bought a tube of Chrysler ATF RTV. I'm scheduled to drain and replace the pan again. But I don't want to do it and get the same results. I may let the pan drip overnight this time, but if it's still slowly dripping, what can I do? How long do I have to wait for the system to stop dripping? Forever? Will the torque converter, cooling lines, etc. keep dripping for a long time?

Really, I just want to do it right this time, without leaks. So if I had an idea of how long is long enough, that would help. Or is the ATF RTV less susceptible to this kind of contamination of the surface with some liquid ATF? (I cleaned before with a paper towel sprayed with brake cleaner).

Also, the Chrysler tube says to just apply, install and torque. Is there no time for skinning the RTV before installation or set time before final torque?
 
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#2 ·
Best to follow the instructions.

The transmission shops seem to bolt things up pretty fast.

I have some Permatex Ultra Black. It says, after applying the RTV: "Assemble parts immediately. Finger tighten bolts until material begins to squeeze out around flange. Allow to dry for one hour, then retighten 1/4 to 1/2 turn".
That would work okay if the bead of RTV is uniform all around, but watch out for the area that has less RTV. A good quality gasket seems to be the easiest way to go, considering that you have drips to contend with.
 
#3 ·
I used permatex grey on my pan. I let it drop about 40 minutes while I hacked up the old pan to fabricate a bracket to mount the wiring harness to my new pan, then stuffed a paper towel up inside the back where the drip was coming down and thoroughly cleaned the transmission sealing surface. Then I applied RTV to the pan only, and immediately before installing yanked the paper towel out (ensuring all of it came out) and fitted the pan straight away. I tested the technique first and I found I had about 20-30 seconds after the paper towel was removed before any ATF would drip down to the sealing surface so I know the surface was still clean and dry.
Mine is dry as a bone after 8000km.

Where exactly is your leak? Could it be the solenoid pack?
 
#4 ·
Skip the RTV. Scrape it all off—every bit of it. Get yourself a good quality pan gasket. Don’t even consider a cheap cork gasket, or anything that’s folded in a box. Good rubberized composition gaskets (usually black in color) are available. If you can’t find one anywhere else, a transmission shop will probably sell you one. Most of these have a few “small” bolt holes to keep the gasket in place with a few bolts, until you get all the bolts in place. If not, use a very small amount of quick dry automotive adhesive on the pan side only, not on the transmission side. Don’t use any other sealant or RTV. The gasket does the sealing.
Tighten the bolts firmly, but not over tight. I go around the pan three times. If you are not comfortable concerning the “tightness “of the bolts, use a torque wrench, still tightening the bolts progressively. Do not overtighten the bolts! The next time you drop the pan, the gasket will stay attached to the pan and you will be able to reuse it—typically 3-4 times or more. If this still drips, then you have a bad pan or damaged mating surface on the transmission.
 
#5 ·
I have since using imo the best oil/trans pan gasket never used rtv or any type of sealant. The gaskets i buy at times are from different named companies but they are rubber gaskets with metal washer type inserts that prevent over tightening . I always look around to do my best in staying away from those cork cork/rubber mixed gaskets.
 
#6 ·
After a couple of gasket tries (including two "professional" ones), I bought a tube of ATF RTV and followed the directions. Namely, clean the mating surfaces, spread a 1/8" bead, bolt it up. No wait, no endless fiddling around to stop that annoying post-transmissional drip, just spread the RTV and bolt it up. ATF was still dripping out when I bolted it together.

And no leaks. None. At least from the pan; i did discover a leak from the solenoid pack and replaced it, but that's a different story.

There's a reason Chrysler used ATF RTV as OEM. It's apparently idiot-proof.

Some have good luck with gaskets, some don't. And yes, the cork gaskets and the gaskets packed with the filter in the kit from NAPA are not the best. There apparently are good gaskets out there, but I got tired of experimenting with it. So far, I haven't heard of a single leak with the ATF RTV when applied according to directions (no waiting to skin, just slap it on there, like Permatex Right Stuff)
 
#8 ·
The time I changed my ATF for the first time in our school shop, I removed the pan, used a 1+ putty knife to clean the transmission mating surface and pan mating surface, then throuoghly cleaned the pan and magnet in our parts cleaner. I laid down a bead of blue RTV on the pan, placed the rubber gasket on top of the bead, inserted the bolts, then put another bead of RTV on top of the gasket - a 'gasket sandwich', if you will. I replaced the filter. I did not wait any time for the RTV to skin or anything, just reinstalled pan and refilled with ATF. I never had any leaks. Given that I did not read any directions/procedures, and it was my first time doing AT service, I'd say I got really lucky! I did read warning after the fact that one has to be careful not to use too much rtv as if a piece breaks off inside the pan, it can cause issues. What I did do wrong was use the incorrect ATF given to me by the local parts store. I can blame only myself for this as as previously stated, I did not read any procedures. I learned shortly thereafter about ATF+4, but that's a whole different story but thanks to the advice on this site, I escaped without any damage to my transmission.
 
#10 ·
Why? I recently had the transmission serviced at a transmission shop. I explained how I had done it previously and they seemed fine with that. When they were done, I asked the technician how the pan removal and filter change went. He said it went fine, "no problems". The first time I had the transmission service done at CT, I came out in the morning and most of the AFT was in a pool under the van. It had to be towed. The service manager said that the tech had only used the gasket, no sealant. I thought I'd be sure I didn't have to do the job again. Also, I had no trouble removing the rtv that was on there when I did my own service.
 
#11 ·
If its what you want to do, its fine but thinking of the manuals i have read and noticed recieved through my career, no one that i have ever worked with used rtv on both sides. Its been so long since i last used rtv but they use to have writtings on the container stating "use only on one side" . As i mentioned above, i dont use rtv at all, just my rubber gaskets and have no problems.
 
#12 · (Edited)
Great. Thanks for the info. I did a little googling and it seems there are differing opinions on the subject. Some do, some don't. The gasket that came with the filter seemed a bit thin to me even though the mating surfaces seemed undamaged and quite smooth. Given what the service manager at Canadian Tire said, I really didn't want to go through the whole procedure again, so maybe I "overcompensated" a bit. Either way, it didn't leak. I appreciate the input.
 
#13 ·
I've had no issues using the thin, black folded neoprene gasket that comes in the filter kits. The cork/rubber gaskets that came with the WIX filter kits ALWAYS leaked. I clean everything good, and apply gasket adhesive/tack-a-gasket to the pan and stick the gasket on with some weight on it for a little while. Then I smear some black RTV on the gasket with my finger, and install it on the cleaned transmission. The thin layer of RTV fills in any scrapes in the aluminum transmission surface. Never a leak. I even removed the pan once and reused the same gasket using the same procedure, and it is still dry to this day. Wish I could get a gasket like that for the differential gear cover.
 
#15 ·
Does anyone have a vendor and/or part number for the high quality gaskets?

I'm pretty sure it's not the solenoid that's leaking, all indications point to a seep right along the bottom edge where the oil ATF kept dripping down when I was doing the pan the last time.

I did like zero10 did, stuffing the paper towel up there, but when I pulled mine out, it was more like 5-10 seconds before the first drip. So maybe I just let the RTV skin over too long and it's not really "adhered" to the transmission side.

If I get this one on without any leaks I will probably never have to change that filter again. Ill pump out and put in fresh fluid for the next 80k.
 
#16 ·
#17 ·
Sheldon, thanks for the link. That is certainly a fair price if it's as good as you say. I wish I had gone with that first, and would have, but nobody had a part link and searches were turning up nothing but generic kits.
 
#18 ·
Well, it's been a while since I tackled this job. I've just been adding transmission fluid every couple of weeks until I finally got a fluid sucker so I didn't have to keep buying new fluid. (I'm keeping it perfectly clean)

I did the job today, got it all cleaned up, dried and cleaned with carb cleaner and got the pan immaculate and the transmission body as clean as I could make it. I put on a nice 1/8" bead of Chrysler RTV around the pan and the bolt holes, did the "leak block" with a paper towel, pulling out at the last second, and got the bolts put in without wiggling the pan. Ran the bolts in finger tight, then ran them in 1/4 turn at a time, crossing back and forth, then brought them up tight, choked up on a 1/4" socket. I let the RTV cure for 3+ hours, then refilled it with ATF.

And it's leaking again. Still just a drop every 10 minutes or so, like the last time I did it, but it's really infuriating. I thought I had this job down pat and was doing everything correctly. I've tried very hard to keep from scratching that soft aluminum and I didn't have any skips in my RTV, only waiting about 5 minutes from squeezing it out to bolting it on.

Now I'm looking for a composition gasket for the 41TE transmission, but not getting any luck. (Where can I find one?) I might order a new pan in case mine is bent or something.

Is there anything else I can try at this point?
 
#20 ·
.... And it's leaking again. Still just a drop every 10 minutes or so, like the last time I did it ....
Ok, IMO it's WAY too much of a coincidence that you would get the exact same, regular leak from a second RTV job. Let's go way back to the beginning. I'm assuming there was nothing leaking prior to your first gasket attempt (if there was, then you should look for a leak somewhere else). How did you get the pan freed-up from the factory RTV? Haynes will tell you to "tap" the pan with a rubber mallet. But, based on my own experience with this, I'm going out on a limb and say you weren't able to pull that off. So what you did to get the pan off might help to explain why it's leaking now. But in any case, find a perfectly flat surface and check the level of the pan edge. If the pan is flat, then check every bolt hole up-close to see if anything is going on with one or more of them. If all of them are ok also, then check the tranny surface to make sure it's flat (can't imaging why it wouldn't be, but it's the only thing left).
With this exact same leak coming back repeatedly, it seems like there's a good chance that something is physically wrong with the parts.
 
#19 ·
Me again; I reported earlier that I had success with the ATF RTV, but that too failed after a few weeks, irritating me no end. I discovered that my pan was slightly warped, and that the aluminum mating surface was damaged such that there was a channel possible all the way through, so even the super-gasket everybody recommends wouldn't work without some additional help. So:

1. I got the Dorman pan with drain through Amazon, $40 or so. Dorman offers 2 pans, the one that's supposed to be for the later gen IV's has a hole in the flange in a different place to hold the wiring harness, and costs $125 or so. It also holds an extra half-quart of fluid. Whoopie. I got the cheaper one, which fits fine, and used a cable tie on the wiring harness.

2. I got the Mopar super dooper steel and silicone gasket, reusable, from one of the on-line suppliers for $35. Be careful there, the first supplier sent me the wrong gasket, but it was so obvious that I spotted it right away.

3. I used some of the ATF RTV to fix the damage channel in the aluminum mating surface after cleaning it with brake cleaner, but otherwise put the gasket on dry with the new pan. The damage was apparently a screwdriver gouge, I suspect by the first "professional" I had service the transmission. At this point, I'm clearly better at it than he was.

After more than 2 months, no leaks, no wetness, no problems. I'm now about $300 in to this project, what with countless quarts of ATF +4, but it's DONE.
 
#21 ·
Samc, I have done just what you have done and dropped back 10 and punted. I have the new Dorman pan and the composition gasket on order to be here tomorrow or the next day. I might have to do what you have done and touch up that area with some RTV.

Cvguy, I'll take that to heart. Yes, there may be a scratch somewhere in the mating surface. The truth is, it's about the roughest milling job I have ever seen on a "sealing" surface, a travesty of machine work, especially because Chrysler make the trans body out of silver colored meringue. But that's not to say there aren't any scratches. Yes, it was a pain to remove the original pan, but I did it entirely by pulling down on the pan, levering between it and the other protrusions on the transmission, not wedging a screwdriver between pan and gasket. I'm going to put my machinists straightedge along the transmission bottom and maybe even scrape it with the flat of a razor blade (I can't sand it for obvious reasons...) but at this point I fear that I bent the bottom lip of the pan more than gouged the metal. Hence a new Dorman pan on the way. (I tried the sideways bonk with a rubber mallet too. But they have to be kidding, no bonking was going to break that RTV free.)

The good news is that overnight it only leaked about 2 ounces, so I can top it off for a few days until I get the parts.

PS: I called the dealer about that composition gasket on Saturday: $75! I have it mailing from http://www.factorymoparparts.com/ (also in Florida) for $32 + $8 shipping. Of course they don't carry a replacement pan so I had to get the Dorman pan from Amazon.
 
#22 ·
... Yes, it was a pain to remove the original pan, but I did it entirely by pulling down on the pan, levering between it and the other protrusions on the transmission, not wedging a screwdriver between pan and gasket ...
Frankly, if someone said they were planning to do what you did, I would have told them it couldn't be done :blink:

I don't understand how you "attached" something to grab the pan, and beyond that I can only imagine the force that was required to rip the RTV open. Did you torque the pan laterally (i.e. in a circular motion)? I have to believe something was bent and skewed in the process of what you did, and hope for your sake the damage was done to the pan and not higher up.

Not trying to be critical in any way of what you did, because what these idiots at Haynes write lead you to believe breaking the RTV seal is no big deal. And just to give you some perspective, I worked a very thin bladed putty knife SLOWLY and carefully around the RTV. I had my eyes right next to the blade, to make sure it wasn't hitting any metal. Cutting this RTV with the metal blade was like going into epoxy, and it took around 25 minutes to work the blade through enough of the stuff to finally release the seal.

I suspect that the pros use a similar method, except they work much faster and will have the pan off in a flash. And because they all seem to use RTV instead of a gasket, any small nicks they do to the metal mating surfaces are probably always going to be taken care of by the glop filling them in. Good luck with this - I hope it works out well for you :thumb:
 
#23 ·
It's a bit hazy, the first time I did this job was a month ago, but I think I just used a regular claw hammer. I tool out all but the 4 corner bolts and then backed the four corners out about 2 turns. The there are about 3 or 4 spots where the pan overlaps the transmission enough to put the claw on "top" of the pan and lever it down a tiny bit. Once you get a corner to start peeling open the RTV and draining the fluid (I didn't have the transfer pump then) I backed the screws out another 2 turns and then went around pulling down on the pan edge and doing other various levering jobs. I do remember that it often took a good bit of force, more than 40-50 lbs of pull on the hammer handle, to get it to start. The pan edge is probably bent down. But when I look at the RTV that came out the last time, the width of the bead that was between the bottom edge bolts and the edge of the aluminum is probably less than 1/8th inch, and that's right where it was getting wet with ATF due to constant dripping. Plus, I'm not kidding, the machining on the sealing surface is very pronounced, like one flycutter blade was 2-3 thousandths longer than the other. I can feel it with my fingernail.

Like all modern cars, I'm sure this was a perfect solution to sealing the pan when it's dry and upside down on the assembly line. Other locations and orientations were probably not considered by the engineers.

Here's to hoping that the composition gasket and new pan true it up.
 
#26 ·
This simple tool works great to separate the pan from the transmission
That's interesting, I've never seen that before. What's the blade material made out of, metal or plastic?

I tried the rubber gasket that came with a no-name filter kit the first time, two of the holes were punched too closely together to make the gasket sit flat when on the pan. The ATF literally gushed out, it took 4 quarts to get me 4 miles home. (Luckily the bad part was near the top or I would have had to tow it.)

I use anti-seize on those bolts every time. I put it on the threads, then wipe it off so it won't get on the flange area when installing.

My biggest issue is that I can only do this job after work during the week and it's usually raining hard in the afternoon in Florida in August. I might have to *Gasp!* clean my garage to do it as soon as the parts get here.
 
#25 ·
To jump into this late: I agree with the guys who recommend a non-cork gasket. I've had good luck with those and no leaks. Using RTV is fine (and cheap) when you're assembling the transmission at the factory, it's upside down and doesn't have ATF dripping over the gasket surface.

I installed a drain plug at the first fluid drain when I got my van with 70K miles on it. the next time I just drained via the drain plug which was quick. The last change I dropped the pan again so I could replace the filter. I used the rubber gasket that came with the filter but let it lay on a flat surface for a few days. I installed it with NO RTV. No leak problems at all. Also, the gasketed pan came right off, unlike when they are glued on with RTV.

My problems were elsewhere. I've heli-coiled half the pan bolt holes so far. At the first change, many of the bolts came out with the aluminum threads still attached. Ugh!

Bill
 
#28 ·
I only use that tool for the pans that are really stuck on.
it is a short tool and lets you tap into the crack between the cover and the transmission.
Since, you are not going in at an angle as you would with a screwdriver or putty knife, the pan has less chance of damage.
For limited clearance, it works very well.

My first choice to get pans off though is a set of non-marring scrapers from Harbor Freight.
Sometimes there is not enough room to use them though.
The scrapers can be sharpened since they dull easily.
http://www.harborfreight.com/4-piece-nonmarring-scraper-set-95832.html

 
#29 ·
if you have a 41TE transmission ie. 4 spd Chrysler I used a felpro gasket. It looks like this http://www.amazon.com/Fel-Pro-TOS18...d=1421451960&sr=8-1&keywords=Fel-Pro+TOS18687

I apply RTV sealant to both sides spreading it with my finger......I install the pan and finger tighten the bolts. Wait 1 hour and tighten as per specs. Never had a leak. You can get the same gasket at autozone for $7.99. DO NOT use a cork gasket or one that comes with the filter. The felpro gasket is rigid but flexible enough to move around.....I used one of the cheap kits that came with the filter. The filter was missing a peg so it wouldnt snap into place and the gasket was too thin it would not stay in place. Get a mopar filter for $12.00 a felpro gasket for $8. Im sure your $3000 transmission is worth the extra $10. Why people cut corners on a tranny I don't get it.
 
#30 ·
Easy fix..When you get those pesky leaks..Just use some RTV Black and Finger squeeze it into spot that slow leak is coming from. let it cure up and done...works great. I sealed many many many many leaks this way and never had an issue. It is kinda mickey mouse but it will work! 190K and no drips, a miracle!
 
#31 ·
To answer the original question about drips, I do the following: Place the vehicle on ramps with the transmission/engine being "hot". Pull the pan and drop the filter....allow everything to drain as good as possible. Once the dripping is done, take your finger and probe the rear transmission hole...more fluid will drain out. Probe that rear hole a few times and eventually fluid will stop coming out...then clean all surfaces with alcohol.
As a side note, I've tried several gaskets and had zero success. Even my service manager says that this pan is not designed for a gasket since there is no flair/ridge. I use RTV and always work in a hurry so that all surfaces are clean upon contact. A helper is good too, wiping up any drips prior to pan contact.
 
#32 ·
I've used the gasket that comes with the fel-pro filter and, to this point, have had no leaks (I have done 3 pan drops now with this van). I do use an inch-lb torque wrench when I re-install the pan and I step it up to the specified torque in a couple of steps and that takes a bit of extra time. But very consistently no leaks.
 
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