gearbox/transfer case leaks

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Joined
Mar 28, 2009
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hey guys.... have a question for all you "cruiser guru's"..

a quick history of the vehicle...
1975 fj40
has had a 350 chev conversion, with a 5 speed tranny conversion by PO.

i bought it around 2 months ago, and have started fixing the usuall problems ( decided to fix things first..so havent even had it off road apart from a quick check to see it worked..lol), and have done a disc brake conversion on the front end ( all new gear), replaced the brake master, clutch master...and the list goes on!!! ( you guys are right..they cost $$$...lol )

i just retuned the motor, as it wasnt running right...had started backfiring through the carb..and also was running on when i turned it off............ turned out the timing was way out... so re-set that...and it is running sweet as! only problem was the clutch was now slipping. so re-adjusted the slave to make sure it was re-leaseing properly..all good...

anyway, i had to do a job 300km away, so took the 40 and towed a small trailer...if i took it lightly..no slipping...but go anywhere near half throttle...instant slip.... not good.

returned home a week later ( no driving while away)..and awoke to gear oil on the driveway!! so dropped the gearbox/transfer case ( damn heavy buggers arent they! )...when i dropped the rear tailshaft...around 3 teaspoons of oil came out from the end where it joins onto the tailshaft brake thing..ah ha.... found the source i guess





can somebody point me in the right direction on how to fix this?? is it a case of remove the whole transfer case to get to the seal..or just the cover that holds the brake thingo on? is there a pic by pic "how to" guide anywhere??


also, on the clutch plate...spoke to my local guys in perth wa. seems i have a chevy flywheel, a standard clutch plate, and a standard pressure plate. they tested the pressure plate which was supposed to be 1500ft lb of pressure...it was making 1300... have a heavy duty bugga on the way rated to 2600ft lb.... so doubt i will have slippage again!!

anyway, here is a couple of pics....

the gearbox

DSC00898.jpg


rear view ( seems to be modded to suit the tailshaft handbrake? )
DSC00899.jpg


the area where the leak is...
DSC00900.jpg


i found somwhere before that tells you what to look for to determine what year your box is..but cant find it now ( arrg), but it seems mine is a 83 box built in june...number 2110 .

any adivice would be appreciated guys... thanks

luke
 
Gday Luke,
aint no guru here by a long shot... but,

Yes theay are damned heavy- wait till you are putting it back in- the t-case alone (and on my own) almost killed me:D

It looks like at the least your rear output shaft seal is leaking.
I rebuilt my split-transfer, exactly the same as yours but it doesn't have the handbrake off the back like yours (goes to the rear drums instead)- however I still feel pretty confident in saying, no, you definitely don't have to remove the Tcase to get at that seal (I don't have to on mine at least).
I don't know exactly where the seal is on your case, but for me it is a case of getting off the staked nut, then sliding off the companion flange, and then the seal is right there accessible in the bearing retainer- pry it out and tap in the new one.
The difference with yours would be the handbrake is somewhere in the way, but it shouldn't differ that greatly.

Did you check the fluid levels in the gearbox and the Tcase? There is a seal between the two, on the transmission output shaft, that often goes, and this can then force the oil from the one into the other- If your tranny fluid was low, and your t-case fluid too high, then this could be helping the problem of the leaky t-case rear output seal (by making the oil level too high).

Hopefully it's just the Tcase rear output seal.
And good luck getting that staked nut off now that you've dropped the thing:D (I had to build a bit of a contraption to bolt to the front output flange so that I could get some strong resistence- breaker bars on both).

Someone who actually knows what they are talking about should be along soon.


---

And by the way, while you should have no problems getting the seal on its own (once you get the part number), if you do end up having to pull the t-case apart and have to get a rebuild kit, shop around a bit- I got mine from bursons, and they had two suppliers for the same thing, one $300-ish, and then once they asked another supplier, one for $180. Same seals, bearings and gaskets- different co.

Lots of manuals to download here
Downloads Index - Page: 1
and lots of tcase threads in this sort of search (helped me immensly)
IH8MUD Forums - Search Results

Good luck,
Hans.
 
thanks for your reply hans.... and good to hear its unlikely i need to strip the case down to fix that seal

i havent checked the fluid levels between gear case and transfer...was on the "to do list". was considering puting one of those filler/drain hose jobs on in case it went anyway....

very good tip regarding the gasket kit prices.... very big differrence in price there!! will "shop around"

and yes..have been using the "search function" lots..heaps of good info, but in this case, i wanted a more precise bit of info....hadnt noticed the manuals index before thouhg..so again... cheers!!

luke
 
The leak between the driveshaft and the flange is from gear oil creeping down the splines of the output shaft. If you change the seal (5 minutes work) it will still leak at the splines. When you re-assemble the parking brake drum to the output shaft, put some permatex on the splined part, so that as you snug down the bolt, the permatex seals the splines.

Usually if the seal has been leaking, it will ruin your parking brake shoes and leaks out between the parking brake drum and the backing plate.

Regarding the slipping, you seem to know that's your clutch. It sounds like you have a replacement, but I would just use Toyota OEM since they are not that expensive and seem to last for decades.

BTW-that is a very desirable transfer case here in the states and would make it easy to put an H55 in an FJ40, preserving the parking brake.
 
cruiser drew, cheers for the tip regarding the permatex......and overall it sounds like a simple job then hey!!! excellent!

as for the clutch, it only set me back another $80 odd for the heavy duty...thought what they heck...gives me much more confidence!!

what sort of $ do these boxes reach in the states?? may be worth my while sending some over ;)
 
Make sure who ever ordered your clutch kit has ordered a short throw pressure plate one, or your going to have engagement and disengagment problems.I just clean the splines and brake drum where the nut seats and use silacone to seal then put your washer and nut on and torque. Good luck
 
again, thanks for the info dargreg... i dont know if they have or not...but the guy is considered a bit of a clutch guru , and spent around a hour measuring things...and looking into what was available....and the 350 conversion is pretty common here......so hopefully

again, good tip with the silicon will do
 
The leak between the driveshaft and the flange is from gear oil creeping down the splines of the output shaft. If you change the seal (5 minutes work) it will still leak at the splines. When you re-assemble the parking brake drum to the output shaft, put some permatex on the splined part, so that as you snug down the bolt, the permatex seals the splines.
Obviously I have a slightly different T-case than this one (no handbrake assembly, shorter output shaft, and different companion flange), and so am only asking in reference to mine, but it seems a bit odd to me that oil would be leaking down the splines unless there was significant wear or something?

I have to borrow few photos here (from Hugh Heifer), but on mine, here's our bearing retainer with the seal
attachment.php

and here it is on the tcase with the splined section of the output shaft poking through,
attachment.php


then as shown on the bottom, you slot the companion flange on over the splined shaft,
Picture5.jpg


torque and stake the nut, and the primary sealing is done between the inserted smooth (hopefully;)) rim of the companion flange and the oil seal- and also of course relying on the tightness of the fit between the companion flange and the splined output shaft (which is a very tight fit).

I am not sure how the handbrake assembly joins onto the splined output shaft- but I am assuming that similar to mine, there is a section that slips into the oil seal (sealing it unless the oil seal is buggered, or the surface of the thing slipping in is buggered), and then a section that slots over the splines- like my companion flange does- sealing from oil unless there is too much wear and the splines are buggered enough to let oil through?

I must be wrong somewhere here, especially if this is a common problem requiring permatex as a solution- but as said it just surprises me that this T-case with the handbrake should leak through the splines while mine and others like it (as far as I know) don't- and don't require any sealant on the spline...?
(unless ours actually seals between the front of the companion flange where it hits up and is torqued up hard against the inner race of the bearing???)


Anyway, I don't know, just for interest, not arguing or anything, just trying to figure it out.

btw, Luke, for a excellent thread on rebuilding a split case, with plenty of great photos, check out Hugh's thread
https://forum.ih8mud.com/40-55-series-tech/188968-split-case-rebuild.html
it helped me alot.
 
thanks very much for the post hans...and also the links!!! just what the doctor ordered.

hopefully there isnt anything more sinister going on...and it is simply the seal gone.....

will be pulling it down and looking further over the next couple of days..so will let you guys know.

again thanks to all who have replied :)

luke
 
all sorted... was a easy job..spent much more time cleaning the box, and detailing it before i put it back. also extended the breather into the engine bay at a nice high point.....

thanks again guys
 
So what did you do? LOL
Did you figure out where it was leaking from? Splines, seal, both, neither?
Curious minds want to know (at least mine does).
Glad to hear you sorted it anyway.
 
hey mate...after using the old clutch plate on the front shaft with some timber( a long enough piece so that it hits the floor allowing for resistance) bolted through it so stop the whole lot spinning, went to remove the nut, and found revealed that the nut hadnt been torqued properly, and was not very tight at all..and not very well punched in to lock it..got to love previous owners!



so cleaned it all up...put in a new seal ( there are 2 sizes i found out....first time thanks to good advice), then used some permatex on the end of the splines and around the washer, and also some on the thread where the nut goes.....got it "close" after putting the permatex on, and as the instructions said, nipped it up after a hour of cure time. then gave the nut a damn good key in with a punch so it was depressed into the grooves..so hopefully no more movement from it again!

put in new oils ( checked both levels prior to draining, and no leaking between the gearbox and transfer), gave the whole lot a nice scrub down, and a fresh lick of paint...beautiful.

have bolted up the new clutch ( after making a alignment tool)..so ready for the install tomorrow

fingers crossed, i wont have to look at it again for a long time!
 
yup, the rear seal for the split case with the ebrake setup is the same as the rear seal on the earlier fj40/45/55 one-piece t-case. it's smaller in diameter than the non ebrake split case version.
 
cruiser drew, cheers for the tip regarding the permatex......and overall it sounds like a simple job then hey!!! excellent!

as for the clutch, it only set me back another $80 odd for the heavy duty...thought what they heck...gives me much more confidence!!

what sort of $ do these boxes reach in the states?? may be worth my while sending some over ;)

Mate,

I would be interested in one of these cases - and an H55 to fit 2F as well!

Did you locate some more with the parking brake installed?
 

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