I have the 6 speed manual trans and it is leaking trans fluid out of the vent hole in the bottom of the bell housing. The leak was only a couple of drops at first but has gotten worse in the past week. I know someone was in the trans before cause of the amount of silicone at the sections where they bolt together. Also, the trans was filled with gear oil when I bought it.

I suspect it is leaking from the input shaft seal of the trans. I won't really know until I take it apart. However, I got some questions.

Is the seal an easy thing to replace? Is it like a typical oil seal or something special? Are special tools required?

Can the trans be removed from the bell housing without disturbing the clutch slave cylinder? I've done clutches on 4x4's before but I have not had this trans out of the truck yet.

Any additional areas where the leak could be coming from?

The clutch seems to engage fine. I will check the clutch disk when it is apart.

Thanks for the help.

 

These transmissions don't have a seperate bellhousing, so no you can't seperate the tranny from the bellhousing. These transmissions also have a pump unlike most manuals, I'm assuming it's right up front like in an automatic, but I'm not sure. That could be leaking. Someone else should know for sure.

 

Best bet would to ask KWIKORDEAD since he has the most relevant recent experience in 6 spds

 

I saw your post and yes I have a lot to say, but not the time to type it out right now.
I'll come back in a couple of hours.

 

Wilbur996 I have strong reason to believe that your pilot bearing has failed and it's allowing your input shaft to wobble. That will chew up your input seal until it leaks.
What I have learned about the ZF-6 transmission is that the input shaft is one piece from front to rear of the transmission. All that movement of the shaft will ruin the bearings and gears, forcing a rebuild.
It's what happened to me, and a lot of other guys as well.
When you get the transmission out, see if you can move the shaft in and out or side to side. If you can get ANY MOVEMENT AT ALL, the transmission requires rebuilding.
The best price that I found on a rebuilt unit on short order was through Fleet Pride in the Seattle area. They have branches all over the US so you should be able to find one fairly easily in your area.

 

Woops, clicked on the wrong button, so I'll continue here.
Removing the transmission is very easy if you have a good tranny jack that you can strap it to. It's VERY heavy at 250+ lb so forget manhandling it. It's just too heavy. The engine is balanced pretty nicely on it's own mounts, but I put a bar across the front anyway to make sure that it doesn't tip it'self into the radiator. I also removed the clamp from the downpipe to help with access on the starboard side of the engine. I still can't decide if I needed to do that because of the clearance issues with the 4" downpipe. I decided to make life easier for myself and just remove the clamp so I could push the DP over if needed. If you have anything smaller than a 4" downpipe this step is not necessary.
There is an ATF cooler for these transmissions and the pipes are very easily removed.
You don't have to remove the transfer case unless you want to. I found it easier to pull both drivelines off and remove the whole unit, TC and all.




Once it's out, it's a simple task of removing the six bolts that hold the TC to the transmission and the thing slides off the tailshaft of the transmission. If it's stubborn, it's because the splines have rusted or something. Six bolts and remove.
Don't forget to separate the 4x4 lever from between the transmission and the TC.

On to the cause of the whole problem: The Pilot Bearing.
For lack of a few little needle bearings you are living this problem.
There are available from Southbend and Carolina Clutch a pilot bushing that is made of Kevlar.

It never wears out like the stupid little pilot bearings do.

From what I hear, it will outlast your present clutch and the next one as well.
It installs in the place of your pilot bearing in the center of the flywheel.
Sorry, no pictures to offer. But what it looks like is a very hard piece of plastic that is machined to fit into the place that you install the pilot bearing. And it goes in VERY firmly, so be careful you don't just pound on it and deform it during the install. It was pretty stubborn when I was putting it in and I was getting a little paranoid of breaking it, but it finally installed all the way down to the shoulder on the bushing.

Well, that's all I can think of right now. Good luck on your repairs and write back if you have any more questions.

 

Kwik,

Thanks for the reply. I remember reading about your trans troubles.

So, this could explain my other problem with the trans. Every now and again it comes out of 4th gear, sometimes 3rd but most of the times 4th. I kinda thought maybe I was not getting it all the way in gear sometimes. It does not happen often. Seems like when u load the trans and then unload it pops out. Kinda like blasting up a hill then taking your foot out of it and coasting, it will pop out.

I've done pilot bearings before and they always seem the hardest to get out. Usually install is much easier. I dread dropping that giant trans out but I hate to pay someone else. Any idea on what a reman trans cost?

Thanks again for help.

Tim

 

Popping out of gear right after lifting from the throttle erases all doubt - you need a transmission.
The pilot bearing on the PSD is one of the easier ones to get out. It's mounted in the flywheel itself, so if it is stubborn, simply remove the flywheel and pound it out from the backside with a big hammer, and a short piece of pipe or similar piece of equipment.
I paid $2450.00 for my rebuilt exchange unit from Fleet Pride in Seattle, WA. Thier billing address is in Dallas, TX. so you might try calling thier central office and see what they have to offer in your area. I thought they were straight up folks with whom I will do business with in the future.
Sorry I don't have a central phone number but here is the Seattle number: 206-343-1500.

 

Damn! $2450.00! That is gonna leave a mark in the wallet. Is that with or without core charge?

I may try the seal and the pilot bearing and see what happens. Since I will need a trans anyway, may as kill this one. The truck dosen't do heavy duty towing at the moment but I also don't like doing things twice. A real dilema.

Kwik,

Any website where I can view the input shaft seal setup? My cd does not show a good view of the part.

Thanks again for the reply.

 

At Fleet Pride the core charge was an additional $1000.00 on the plastic. They gave it right back the day they got the old one back.
I hear you about doing things twice. I hate it too.
I don't have a good picture of the input seal, however if my memory serves me correctly, it appeared that the throw out bearing guide tube was removable via three bolts. The seal might be mounted on that tube and that would make replacing the seal a piece of cake.
If it's mounted underneath the tube, then you will need to dig it out of there. I have a seal hook that is perfect for that job, it's shaped like an eagle's beak and it does a great job.
Here's one from Napa that similar to mine.
http://www.napaonline.com/MasterPage...on=Seal+Puller
What I would do before you use it is to grind or file the edges down along the curved part so that it's shaped like a true birds beak. In other words make the curved part rounded instead of looking like a piece of stamped steel. If you leave any sharp edges it will gouge out a groove in the shaft and create a channel for oil to make it's way out. If that happens then there is no way to stop the leak except to replace/remachine the shaft to get rid of the gouge. This part is VERY IMPORTANT. Pay close attention to make sure you don't scratch the shaft and you will be ok.
Customer has arrived, gotta go.

 

Wilbur PM me your email address an I can send you a short PDF.

 

Kwik, Amiller,

Thanks for the help. I have the pictures I need and I already the seal puller tool in the toolbox. All it needs is a bit of filing and good to go. I'm sure this is not gonna be a fun job. Now to order that kevlar pilot bushing and find the seal. Not sure when all this will happen since I got to do it outdoors. I will you guys know what happens.

Thanks again for the help. This place is great!

 

Old thread revival but same trouble now. Input shaft seal appears to be leaking...just got wise to it this morning when I found a silver dollar sized oil leak underneath the bottom vent hole on the passenger side and an obvious drip point. Some streamers of oil tracing their way along the underside of the case behind that point so it was leaking yesterday going down the road.

Probably because of the bad pilot bearing setup that damaged it before I had the clutch done about a month ago. Is the input shaft seal replaceable from the outside of the box like the tailshaft seal is without taking the whole thing apart or is that game over for that transmission? The funny thing is the shop said the input shaft looked still looked okay and didn't have any play in it, but this is all second hand info. They used the Dorman solid bronze bushing with the new Luk clutch kit this installed for me. (Also did the rear main seal which was also leaking.) Either way this sucks big time since the transmission has to come out again and a new one would be a bill so large I almost wouldn't bother with it.

 

You have to split the trans open to replace the input shaft and pocket bearing, I would do all the bearings while in there.
I did this last year on a Zf5 which is similar to ZF6.

 

Just so clear...replacing the seal for the input shaft requires splitting the trans open, or were you referring to the entire input shaft?