Transmission Output and Transfer Case Input Seal (Help)

I've had a leak under my truck for awhile and finally decided to get it checked out. The dealer diagnosed it and told me the transmission output seal and transfer case input seal need to be replaced. They want $1000 to do the work which I can not afford. Has anyone ever done this work and know how easy it is to do, or know of any write ups? I did a quick search but couldn't really find any useful info.

My truck is a 2004 Tacoma v6 with an auto trans.

 

There's no way a dealer diagnosed a tcase input seal leak without pulling the tcase. Trans output is feasible if it's dripping between the trans and tcase. Probably $300-$400 to replace at an independent shop or $10 and a Saturday afternoon in the garage.

All super straightforward work to drop the tcase and replace the trans seal but it will take a few hours for sure.

 

The leak is between the transfer case and transmission. I'm not sure if they dropped the tcase to check it out or not, but that's what they said it was.

Thanks for the info btw. I decided I'm going to do the work myself and just ordered the seals.

 

The dealer is trying to rape you. Please don't let that happen. I have a couple videos that can help you out. They are part of a 3 part series that my buddy Sean and I made replacing his auto trans on his 2002 4runner. The first and the third videos are what you need. The first video shows how to pull the transfer case. The end of the third video shows you how to reinstall it.

We don't show replacing seals but I'm certain you can figure it out. You just need a seal puller. Here's a link to one that I know people have been successful with:

$19 Lisle 58430 Shaft Type Seal Puller

https://www.amazon.com/Lisle-58430-...=1505877501&sr=8-1&keywords=lisle+seal+puller
There's also other tricks like drilling small holes on opposing side of the seal, screwing in a couple screws and then using a pliers or channel locks to grab ahold of the screw head and pulling out the seal. If you search YouTube, I'm sure you will find videos on seal pulling. The only thing you have to be careful with is scoring the shaft. You want to use a technique that will not damage the output or input shafts. To install the new seals, all you need is a piece of pipe or something like it that has close to the same diameter as the seal. Tap the seal in place and you're good to go. If you can't find the right diameter pipe or other tool, you could just drive it in place by tapping around the circumference of the seal with a plastic mallet.

If you don't have much experience wrenching and/or you don't own many tools, maybe you can find a friend or family member to help you. Also, you have a huge network right here on this forum. I'm sure another 1st Gen Tacoma Brother local to you would help you out if you put out a request for assistance.

If you have any questions, just ask. Good Luck!

Here's the two videos:

https://www.youtube.com/embed/oZDSjlxl2Q4


https://www.youtube.com/embed/T4YY3IfnzaQ

 

@Timmah! I can't thank you enough for all the info! These videos will really come in handy when I do the seals.

I do have one question that the video did not answer. Should a gasket or rtv be used between the tcase and tranny, or is it just metal to metal?

 

How far are these seals driven in? Sometimes they should be flush with the case but other times Toyota specifies a "drive in depth" that requires a special service tool (SST). (I didn't watch the video, so maybe it says it there.)

 

They mate up metal to metal. There is no fluid running in the space between the two so gasket material is not necessary. When you see a leak at the juncture between the transfer case and transmission, it means either the output seal on the transmission is leaking or the input shaft seal on the transfer case is leaking. Or, they could both be leaking. A dab with a paper towel and examining the color and viscosity of the fluid should tell you which one it is. If it's both leaking, the fluids would be mixing at the bottom and then leaking out. Once you get it apart, regardless of which one was leaking, it would be smart to just replace both.

The input shaft of the transfer case slides into the output seal on the transmission. This seal should be easy to pop out with a 2 jaw puller, hooked seal puller or maybe a screwdriver. The transfer case seal is fitted around the input shaft. This is the seal you have to be careful with that you don't score the shaft.

 

We didn't replace seals in this video so we don't discuss it. I haven't looked at the FSM for the specifics on this but a safe procedure is to take note where the seal is currently seated and drive in the new one only that far. It's nice when there's a natural stop and you just drive it in all the way but that's not always the case. The front differential axle seals don't have a natural stop and you have to carefully drive them in to the correct depth.

 

I don't understand why you're saying no way they could diagnose a transfer case input shaft seal leak without pulling the transfer case. If there is gear oil dripping out between the juncture of the transfer case and auto transmission, it's a pretty good bet that the input shaft seal on the transfer case has developed a leak. It could also be leaking from the seal housing to main transfer case housing (not sure if these are the right terms), but if that's the case, you're going to be removing it, resealing it with sealant and putting it back on with a new input shaft seal anyway.

 

I was thinking manual trans that uses gear oil instead of red ATF. Still though, I'm not sure I'd be able to call both seals going out based on the mixture of fluid. Plus the odds of both being bad are pretty slim....I've handled 3 or 4 tcases with over 200k and they are all perfectly dry around the input shaft. I've only ever seen/heard of issues with the rear trans seal on manual truck.

 

I hear you. When I helped pull my buddies transfer case, his tcase input shaft seal was perfectly dry too. There's two schools of thought, replace it while you're in there because if it develops a leak later, you have to do all that labor again to get in there. And then there's the school of thought that says"If it ain't broke, don't fix it". We had the opportunity to replace the tcase input shaft seal and rear main seal on the engine and opted to leave both alone because neither were leaking. As some of us have learned the hard way, it's sometimes better to not mess with something because you might create a problem that you didn't have before.

One thing I forgot to ask the OP is how bad is the leak? Does it leave a puddle under the truck or just a drip or two. I have signs of a leak in the same place but it's so slight that I don't worry about it. Every time I get under my rig, I see it a little wet and a drip of oil but it's nothing to lose sleep over. OP, maybe just watch the leak and get a better idea how bad the leak really is. If it's not that bad, maybe just keep an eye on it and do it when it gets much worse. Engines, transmissions and transfer cases will develop leaks over time but most of the time you can just live with it because it's not that bad.

 

Good work! But I think your buddy needs some mouse traps in his garage!

 

The leak has been developing for about a year. At the first the Tcase just had a very small area with oil residue on it. I didn't worry about it at that point. I still don't have any puddles forming under my truck, but now the entire Tcase is covered in oil residue.

 

You absolutely lost me on that comment. Did you see mouse droppings in the videos? These videos were shot at my house and I don't have a mouse problem as far as I know.

 

Did this just yesterday. Had the trans out for rebuild and I'm replacing the seals on the tcase input and both outputs. Input was straight forward. Remove the 5-6 12mm bolts and pull the cover off. Knock old seal out carefully drive new seal in. Clean off the old sealant (red scotch bright) and revealed with Toyota orange fipg.

 

So instead of using a seal puller to remove the seal, you just took off the cover instead. I just question which method is better. If you pull the cover, you have the extra work of scraping off old gasket material and resealing it. But, with a seal puller, you might score the shaft if you don't do it right. Decisions, decisions. Thanks for sharing this method.

 

I did not have a seal puller or anything that would fit over the shaft to drive the new one on. Resealing was easy to me using a piece of red scotch brite to clean the surface. Then a bit of brake cleaner to remove any oil. Then a small bead of toyota orange fipg around the area and bolted back together.

 

Thanks for the response back. Your method sounds like a good one. Thanks again for sharing it.