Discussion: FIPG vs. other gasket materials for a perfect tranny pan seal
12-17-12, 01:05 AM
#1
Lexus Champion
Thread Starter
Discussion: FIPG vs. other gasket materials for a perfect tranny pan seal
there seems to be a lot of debate and discussion here on CL regarding FIPG vs. other gasket materials, so I thought I would write a quick primer on the various gasket sealing choices and which is best and why.
FIPG
Form-in-Place Gasket (FIPG) is what your Aisin transmission had applied at the factory, by a robot, on brand new clean dry parts. And it seals great when applied in a factory environment or other clean off-vehicle assembly area. Unfortunately, for doing your own transmission, or even at the dealership, FIPG is the wrong choice. The reason is, in order for FIPG to get a reliable seal, it depends on two things, proper consistency of application, which is tricky if you are not an industrial robot or a birthday cake icing pro, but that is not even the main reason it fails for so many who try it.
FIPG depends on both mating surfaces being perfectly clean & dry and oil free - this is the condition of the parts when they are new, or if you completely rebuilt your transmission in a clean area, but for most of us, - we take the pan off, clean it well, and then are going to bolt in back onto a car that is continuously dripping tranny oil while it is off.
Transmissions still in the car keep seeping fluid as long as the pan is off, so while you can take a solvent and get the pan mating surface side perfectly clean and dry before applying the FIPG, it is next to impossible to get the car side clean and dry and get it to stay that way while reattaching the pan, thereby you end up having some spots where a little oil gets on the sealing surface during pan reattachment, and that is where there is not a complete seal, resulting in leaks later on.
Furthermore, you really risk your transmission's health when some of that FIPG squeezes out inside the transmission pan, and pinches off and is now floating around and clogging up your stainer, passages, etc. - and you won't even know it happened until you pull the pan off the next time, and by then it can be too late!
CORK-RUBBER
this is a poor choice for our Aisin transmissions, the cork is extremely sensitive to deformation due to even the slightest over or under torque torque of any mounting bolts. There are a few rare transmission pan designs that feature stand-off areas around each bolt that protect from gasket deformation from over-torquing and on those select trannys, cork or cork/rubber would be a good choice to use, but Aisins are not this type of pan design, so avoid cork on your Lexus at all costs!
BLACK RUBBER TYPE
these black rubber flexible gaskets tend to leak, they squeeze out over time, just like the cork/rubber ones above. Avoid.
BLACKISH COLORED "-PRENE" GASKETS
these rigid gaskets usually have the suffix -prene as the technological miracle gasket material they are based on, the most famous example is Fel-Pro's transmission gasket with Fel-CoPrene! - these gaskets actually seal very well, and even have that cool feature where the holes are smaller so the gasket and bolts all stay put for you! --- I personally really like Fel-Pro brand gaskets, but the problem with these and all of the "-prene" blackish colored gaskets is that if you ever have to do the job again, getting them off is a complete nightmare! - Imagine hours with some kind of grinder brush on your back, trying to get the old gasket off the car - a wicked job waiting on you, if you ever have to change the tranny filter or clean the pan or change a solenoid again!
FIBER
this is the correct choice - the best fiber gaskets are kind of a cardboard looking brown color, and look shiny, like it has been painted with shellac - the gasket will be in a large flat box as this material will not take any kind of folding or bending - this fiber material will tolerate the surfaces being slightly oily and is also forgiving if you happen to not get all your bolts torqued identically. You also eliminate the possibility of contamination of the transmission internals, a huge problem with FIPG, as fiber gaskets are correctly used no sealant. - look at the chunks of FIPG in yamae's transmission pan pics to see what a huge chance you take with FIPG
How to get it to seal the first time and never leak (even after years!):
1. Use a fiber gasket or -prene gasket, I like fiber so I can get it back off easily - In any case, the gasket you should use will not be foldable, it needs to be a rigid type, you will know it is the right type by the large box (since it cannot be safely bent or folded)
2. Get your sealing surfaces clean & dry using a solvent that evaporates completely i.e. brake cleaner
3. Make sure your fiber gasket has not been bent or folded at any point on it's way to your pan!
4. Torque your pan bolts to correct Aisin specification using a high quality torque wrench (65 inch-pounds for our LS400's A340E series and most other Aisins)
I hope this guide has clarified all of the mystery about getting your Lexus pan to seal first time! - PS - a good quality 1/4" torque wrench is the best money you will ever spend!
FIPG
Form-in-Place Gasket (FIPG) is what your Aisin transmission had applied at the factory, by a robot, on brand new clean dry parts. And it seals great when applied in a factory environment or other clean off-vehicle assembly area. Unfortunately, for doing your own transmission, or even at the dealership, FIPG is the wrong choice. The reason is, in order for FIPG to get a reliable seal, it depends on two things, proper consistency of application, which is tricky if you are not an industrial robot or a birthday cake icing pro, but that is not even the main reason it fails for so many who try it.
FIPG depends on both mating surfaces being perfectly clean & dry and oil free - this is the condition of the parts when they are new, or if you completely rebuilt your transmission in a clean area, but for most of us, - we take the pan off, clean it well, and then are going to bolt in back onto a car that is continuously dripping tranny oil while it is off.
Transmissions still in the car keep seeping fluid as long as the pan is off, so while you can take a solvent and get the pan mating surface side perfectly clean and dry before applying the FIPG, it is next to impossible to get the car side clean and dry and get it to stay that way while reattaching the pan, thereby you end up having some spots where a little oil gets on the sealing surface during pan reattachment, and that is where there is not a complete seal, resulting in leaks later on.
Furthermore, you really risk your transmission's health when some of that FIPG squeezes out inside the transmission pan, and pinches off and is now floating around and clogging up your stainer, passages, etc. - and you won't even know it happened until you pull the pan off the next time, and by then it can be too late!
CORK-RUBBER
this is a poor choice for our Aisin transmissions, the cork is extremely sensitive to deformation due to even the slightest over or under torque torque of any mounting bolts. There are a few rare transmission pan designs that feature stand-off areas around each bolt that protect from gasket deformation from over-torquing and on those select trannys, cork or cork/rubber would be a good choice to use, but Aisins are not this type of pan design, so avoid cork on your Lexus at all costs!
BLACK RUBBER TYPE
these black rubber flexible gaskets tend to leak, they squeeze out over time, just like the cork/rubber ones above. Avoid.
BLACKISH COLORED "-PRENE" GASKETS
these rigid gaskets usually have the suffix -prene as the technological miracle gasket material they are based on, the most famous example is Fel-Pro's transmission gasket with Fel-CoPrene! - these gaskets actually seal very well, and even have that cool feature where the holes are smaller so the gasket and bolts all stay put for you! --- I personally really like Fel-Pro brand gaskets, but the problem with these and all of the "-prene" blackish colored gaskets is that if you ever have to do the job again, getting them off is a complete nightmare! - Imagine hours with some kind of grinder brush on your back, trying to get the old gasket off the car - a wicked job waiting on you, if you ever have to change the tranny filter or clean the pan or change a solenoid again!
FIBER
this is the correct choice - the best fiber gaskets are kind of a cardboard looking brown color, and look shiny, like it has been painted with shellac - the gasket will be in a large flat box as this material will not take any kind of folding or bending - this fiber material will tolerate the surfaces being slightly oily and is also forgiving if you happen to not get all your bolts torqued identically. You also eliminate the possibility of contamination of the transmission internals, a huge problem with FIPG, as fiber gaskets are correctly used no sealant. - look at the chunks of FIPG in yamae's transmission pan pics to see what a huge chance you take with FIPG
How to get it to seal the first time and never leak (even after years!):
1. Use a fiber gasket or -prene gasket, I like fiber so I can get it back off easily - In any case, the gasket you should use will not be foldable, it needs to be a rigid type, you will know it is the right type by the large box (since it cannot be safely bent or folded)
2. Get your sealing surfaces clean & dry using a solvent that evaporates completely i.e. brake cleaner
3. Make sure your fiber gasket has not been bent or folded at any point on it's way to your pan!
4. Torque your pan bolts to correct Aisin specification using a high quality torque wrench (65 inch-pounds for our LS400's A340E series and most other Aisins)
I hope this guide has clarified all of the mystery about getting your Lexus pan to seal first time! - PS - a good quality 1/4" torque wrench is the best money you will ever spend!
Last edited by LScowboyLS; 02-22-13 at 04:35 PM.
12-17-12, 01:53 AM
#2
I disagree, this isn't a guide but does make a good place for discussion of the pros and cons of each. Toyota specified FIPG from the factory for a reason, and continues to do so (as do many other OEMs). However this is a personal choice to make, so the pros/cons of all options should be presented.
Personally i've seen both oil pans and trans pans leak. But while most of the FIPG (oem) seals i've seen leak have taken over a decade to start, the bulk of the fiber/rubber seals seem to leak far earlier.
FIPG is a more finicky sealant to apply than a simple cork gasket, but when done properly gives amazing results.
cleaning both surfaces and applying the correct torque is the right way to go for sure though.
Personally i've seen both oil pans and trans pans leak. But while most of the FIPG (oem) seals i've seen leak have taken over a decade to start, the bulk of the fiber/rubber seals seem to leak far earlier.
FIPG is a more finicky sealant to apply than a simple cork gasket, but when done properly gives amazing results.
cleaning both surfaces and applying the correct torque is the right way to go for sure though.
12-17-12, 02:17 AM
#3
Lexus Champion
Thread Starter
FIPG just too dangerous to use, because so many folks will invaribly have some squeeze out into the inside of the transmission, and never know it, until the transmission fails - and then there is is point I mentioned that it is near impossible to not have the sealing surfaces or the FIPG get oil on it on the car side when trying to get a seal on a transmission still on the car.
If I was rebuilding transmissions off the car in a really clean area, and I had a boroscope to inspect my work from the inside, then perhaps FIPG would be fine, but I don't and neither does most everyone else here on CL
If I was rebuilding transmissions off the car in a really clean area, and I had a boroscope to inspect my work from the inside, then perhaps FIPG would be fine, but I don't and neither does most everyone else here on CL
12-17-12, 02:35 AM
#4
FIPG just too dangerous to use, because so many folks will invaribly have some squeeze out into the inside of the transmission, and never know it, until the transmission fails - and then there is is point I mentioned that it is near impossible to not have the sealing surfaces or the FIPG get oil on it on the car side when trying to get a seal on a transmission still on the car.
If I was rebuilding transmissions off the car in a really clean area, and I had a boroscope to inspect my work from the inside, then perhaps FIPG would be fine, but I don't and neither does most everyone else here on CL
If I was rebuilding transmissions off the car in a really clean area, and I had a boroscope to inspect my work from the inside, then perhaps FIPG would be fine, but I don't and neither does most everyone else here on CL
Right.Aisin factored in FIPG when they built the transmission, including the possibility of there being a small amount of fipg in the system at any time since assembly isn't "perfect".
Yes, it is, in fact, possible to get the trans side of the surface clean. Brake cleaner and a rag after scraping it clean (lightly) is all you need. the placement of the bead on the pan is actually the more finicky aspect, since it must be consistent AND properly placed.
slightly more difficult, yes, but by no means "Dangerous" as you make it out to be. And FIPG properly applied will easily outlast any cork/fiber/faux rubber gasket.
12-17-12, 05:15 AM
#6
Also note, that if these things were as dangerous as you say and clogging up the transmission, how were they so easy to get out? The strainer did it's job, and not all of what you showed was identified as just FIPG. (majority of it looks like standard friction material)
12-17-12, 06:03 AM
#7
everything doesnt have to turn into a debate here.
fipg or not, its all about the mechanic who fixes the car...about that picture u posted, if a thin bead was used in between the bolt holes it would have spread nicely and it wouldnt have been an issue. the draw back or trade off for using that stuff is it takes sometime to dry and most mechanics are flat rate
fipg or not, its all about the mechanic who fixes the car...about that picture u posted, if a thin bead was used in between the bolt holes it would have spread nicely and it wouldnt have been an issue. the draw back or trade off for using that stuff is it takes sometime to dry and most mechanics are flat rate
Last edited by python; 12-17-12 at 06:07 AM.
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12-17-12, 09:00 AM
#9
If a transmission calls for a chemical sealant to be used, typically that sealant type is designed to be safe for consumption by the transmission. Obviously you don't want a lot going though they system but particles small enough to pass through the strainer/filter are safe for the transmission and any excess should be caught. What Yamae found is not uncommon and perfectly fine. The more concerning things in his pictured were the metal particles, not the sealant!
12-17-12, 05:05 PM
#10
Moderator
Yamae never said he was having any problems with the transmission. Of course it leaked, but after how long?
Also note, that if these things were as dangerous as you say and clogging up the transmission, how were they so easy to get out? The strainer did it's job, and not all of what you showed was identified as just FIPG. (majority of it looks like standard friction material)
Also note, that if these things were as dangerous as you say and clogging up the transmission, how were they so easy to get out? The strainer did it's job, and not all of what you showed was identified as just FIPG. (majority of it looks like standard friction material)
After the job, the 5th gear is always selected in the same condition. The problem was completely gone. I don't know the exact cause of this but the job was clearly the turning point. I had done the drain and refill 2 times in spring and in summer this year prior to the gasket adding job but the no shift problem was unchanged after those 2 refills.
The leak had started only a few months after the job was done at the dealer. It was just a little bit at the beginning but it has been increasing as time goes on. The bolts were tightened once by the dealer but the leak was not stopped or should I say it was increased. The manager did not have any big confidence to stop the leak and that made me to decide to stop it myself using a gasket selecting carefully.
The job fixed the leak problem. Other than that, the intermittent no shift problem was gone and also each gear shifts smoothly compared with before. It was smooth enough before for me but now I almost cannot notice the shifts. I need to check the tachometer to confirm the shift now. I think I must add one more important item about the ATF amount I drained and obtained during the job at my next post.
Last edited by Yamae; 12-17-12 at 05:20 PM.
12-18-12, 11:48 AM
#12
Lexus Champion
Thread Starter
there is no reason to risk FIPG inside the transmission or a bad FIPG seal by trying to get the sealing surface perfectly oil free on the car side, and keep it that way during pan reattachment on a vehicle that is still continuously seeping/draining fluid, when a high quality fiber gasket will seal perfectly with no contamination risk
12-19-12, 04:13 AM
#14
there is no reason to risk FIPG inside the transmission or a bad FIPG seal by trying to get the sealing surface perfectly oil free on the car side, and keep it that way during pan reattachment on a vehicle that is still continuously seeping/draining fluid, when a high quality fiber gasket will seal perfectly with no contamination risk
http://www.yotatech.com/f2/trans-pan...tozone-190974/
https://www.clublexus.com/forums/ls4...ssion-pan.html
im going to keep any further comments to myself..lets just say im very picky about who performs work on my car
12-19-12, 08:08 AM
#15
I had a trans pan leak fixed on my first gen with FIPG and two years later it is leaking. I believe the problem was in the application, and/or the fact that I drove the car some 60 miles at freeway speeds within two hours (or less) of the job being done. The mechanic told me nothing about how the FIPG needs to cure and I didn't know any better (at that time). I am choosing to use FIPG again to fix the leak (albeit with a different mechanic). The work is being done (hopefully) next week. Two questions:
The diagram someone posted of how to apply the FIPG beading shows a 2mm to 3mm line of sealant around the pan, and shows the sealant goes on the inside of the bolt holes (not the outside). Got that. Does anyone know if the bead/line of sealant is 2mm to 3mm all the way around? Or is it applied slightly thicker at the bolt holes and thinner in between? I could not tell from the diagram.
Secondly, when I googled how long the FIPG takes to cure, some say 2 hours before you should even start the engine (after having filled with ATF of course), and others say it takes 15 to 16 hours before the FIPG to "completely cure". Which means that if you wanted to be absolutely sure, you drain the pan, clean everything and seal it back up and then let it sit overnight before filling it up with ATF the next morning. Unless someone tells me otherwise, that is what I am going to ask the mechanic to do this time. I don't want to have to revisit this problem in another few years, so I am willing to put up with the inconvenience of not having the car if the wait is worth it (for peace of mind). Out of the factory, the transpan seal with FIPG lasted about 14 years before it developed a leak.
The diagram someone posted of how to apply the FIPG beading shows a 2mm to 3mm line of sealant around the pan, and shows the sealant goes on the inside of the bolt holes (not the outside). Got that. Does anyone know if the bead/line of sealant is 2mm to 3mm all the way around? Or is it applied slightly thicker at the bolt holes and thinner in between? I could not tell from the diagram.
Secondly, when I googled how long the FIPG takes to cure, some say 2 hours before you should even start the engine (after having filled with ATF of course), and others say it takes 15 to 16 hours before the FIPG to "completely cure". Which means that if you wanted to be absolutely sure, you drain the pan, clean everything and seal it back up and then let it sit overnight before filling it up with ATF the next morning. Unless someone tells me otherwise, that is what I am going to ask the mechanic to do this time. I don't want to have to revisit this problem in another few years, so I am willing to put up with the inconvenience of not having the car if the wait is worth it (for peace of mind). Out of the factory, the transpan seal with FIPG lasted about 14 years before it developed a leak.