203 doubler - 88 splicase leak

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kcustom73

kcustom73

Stretched it...
Joined
Jun 26, 2007
Threads
62
Messages
694
Location
Ottawa, ON, Canada
The other day I took the 40 on a little highway trip and when I came back parked it back in the garage as I usually do. Later in the evening I went into the garage to take a look at something and I walked in to the smell of gear oil. Took a peek under the 40 to find a 12' puddle of gear oil under the transfer cases.

For the last week or so, I've left it parked in the shop and I've noticed that it keeps dripping. Now I've checked all the levels and I pretty sure the oil is coming from the doubler and dripping between the double and splitcase (see below for leak area)



Now I did check the level in the splitcase and found it to be overfilled a bit so I'm thinking the cases could be a little over-pressurized (I've got both cases and diff vented to a filter under the hood).

Now I've ordered a gasket set for the splitcase and will be pulling it off the back of the doubler to figure out where the leak is coming from. I've done some searching on MUD for some info and the only real info I found was on Chicago's build (almost same setup - my setup is GM 6.5 turbo diesel, 4L80e, 203 doubler, splitcase).

Now I'm trying to figure out what caused the leak. It could be something like Chicago's build and something is loose. Can the vibration of the diesel plus the length of the doubler/splitcase combo be just to much for the one cross member at the transmission? Maybe I should add a second cross member at the back of the splitcase to support all the weight...

What do you guys think? (here are few more pics of the setup).



 
dumb questions first
12 foot puddle or 12 inch?

are all the bolts tight?

outside of that, either threads or the oil seal (where ever it is) is probably leaking..... looks like a new install, so it probably would be a loose bolt and/or leaking from the threads (I just fixed this issue on mine).

vibration? sure, especially if locktite wasn't used on all the various points. I had a heck of a time on my 1st FJ40 keeping bolts in the rear driveshaft - which I presume came from the shaft getting bent one or every time it got thrown out of the rig.


and where is the bolt for where the arrow you placed at?
 
It looks like your crossmember should be more than enough for your setup. Having more than one can cause a whole bevy of other problems
 
oops... 12 inches for the puddle ;)

I also saw that MUD member Boots has a very similar setup (running a 6BT instead of my 6.5) on his 60 and he's only running one cross member and he's got a lot of mileage on his setup without issue.

I've had to take this all a part a few time during the build so I might have forgotten to tighten or Lock-tite something, so I'll start there and see what happens.
 
Yes, pretty much the same set up with only one cross member. I did get a little leak a couple years after initial install and I had some loose bolts. After tightening them up it hasn't leaked since. I also had the vents ran into one line but have since ran them separately.
 
Boots good to know about the leak... lets hope it's something simple (still sucks that I have to rip everything apart to find out)... Did you run all your separate vent lines to a single spot under the hood? Could explain why the splitcase was over filled, oil might have been pushed from the doubler.
 
If you pull the split case, add a good helping of RTV to the splines on the input shaft when reassembling. There is an o-ring there but it is often not enough to stop oil migration.
Oil migration is the only way to overfill it...
 
kcustom73 said:
Did you run all your separate vent lines to a single spot under the hood?
Click to expand...

Right now I just ran a short piece down the side to the skid plate. I will eventually run them to a spot under the hood but I haven't run any deep water for a while so I haven't worried about it yet.
 
A friend is running your same setup under his buggy and had the same issue. He swapped out the lock washers for the bolts that connect the transfer cases together for the "wave" style tension washers. He's never had a leak since (from the transfer cases) and he wheels almost every weekend
 
The bolt wasn't missing, just removed before the picture to check the leak.

Boots, I don't do much water crossing also, so I'll check what I can do for the vent lines.

Mr jits, thank you for the info. I just got the gaskets in yesterday, but gone out of town for business the next few days. Won't be able to dig into it until next week. I'll keep everything in mind when putting it back together. Lets hope it something as simple as a loose bolt.
 
Well finally got around to pulling the splitcase apart. Looks like the oil is coming from the rear bearing on the output shaft of the doubler. Pictures below are from the original build.







Think I'll keep digging into the doubler and see if I can seal the bearing from both sides. I've gone this far so I might take the time and finish pulling the 203 and check all the bolts mounting the adapter to the transmission.

I also wonder if my fill port on the 203 is to high and the case has to much oil, letting it out through the bearing. Folks with the 203 where did you put your oil filler and how high did you guys put it?
 
Can you put up a pic of where your fill port is? I have a 203 doubler setting out here (not something I built) and I can look at it to see where the fill port is at on it. I have no history on the doubler.

Don
 
Hey Don,

The fill port on mine is something I added after I made it into a doubler. I had measured where the port was on the original 203 and put the new one in about the same place. Here's a pic of what mine looks like. The bottom of the fill port is 4 inches from the bottom of the PTO cover. If you could measure yours, maybe I could see if I've got to much oil in mine.

 
My 203 doubler is sort of buried at the moment, but I was able to see both sides from several feet away. I don't see any fill port on it. At the moment I don't have time to dig any closer to it, but may have time this evening. Anyway, I'll try to get closer this evening.

Don
 
My final fill port ended up being the top center bolt on the side cover plate. I found mine shifts a little better with oil to that line.
 
Final update...

Never gave an update on the problems I was having with my twin case setup. I was finally able to figure out where the leak was coming from.

I always installed the splitcase to the 203 while everything was under the 40. So I tried assembling the cases together while on the bench and found the issue. What I found was that the clip holding the bearing in on the 203 output shaft was not letting the front of the splitcase to sit completely flat against the back of the 203. There's a bit of a machined area in the splitcase housing for the bearing & clip to sit in, but the clip was just not sliding in. This left a little gap at the top of the assembly and leaving a bit of a gap for the sleeve that goes on the output shaft of the 203 to seal against splitcase seal. A little grinding with a dremel and everything fit together well.

Now that everything is assembled, the 40 as never run better. Less vibration, better acceleration, less heat... everything said, the 40 is much happier. Having things missed aligned just a bit is no good :(

Lesson learned... if you can, pre-assemble on the bench ;)

Thank you to everybody who helped out.
 
Bringing this one back...

Well after thinking I had everything fixed with these cases, I have a new problem with oil going missing...sort of...

After getting everything fixed, went off roading with some of the TNTLC club guys and everything went great. A couple of weeks later the splitcase started getting a little loud. So check the oil and it's low, by a lot (half a liter). So fill it back up, do a little more driving (20-30 km) and the splitcase starts making noise again. Check the oil level again and the splitcase has lost almost another half liter.

Park the 40 in the shop and didn't have time to check it out until last week while on holidays. Decided to do some investigating and there doesn't seem to be any leaking anywhere. I decide to open the fill plug on the 203 and oil just starts pouring out. After the 203 stopped draining, almost a liter of oil had come out (pretty much what was lost from the splitcase)

I'm sure I put everything back together (there was no left over parts... :) ) Check the vent lines to see if oil might be migrating through them, they where dry. Oil is only going one way (the 203 sat over filled for weeks and the oil never migrated back to the splitcase). So not really sure how the oil is getting pumped from the splitcase to the 203.

Anybody with more knowledge on this setup have any ideas...
 
peesalot, can that much oil travel the splines? It would explain why it's only going one way. Silicone on the splines was the only thing I didn't do. Didn't think oil would travel down the splines to that extent. Oh well, time to rip it apart again (getting real good a building a splitcase ;) ) I'll order some gaskets after the holidays. Might take the time to see if I can raise the tail end of the drive train to get a little more clearance under the splitcase when off roading.
 
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