H55F gearbox, do you need to and how to tighten rear nut on main input

Hi Pop

sorry for late reply

Did you tension your nut just as precaution or because you had noise or other symptom?

My box does make a bit of noise when under load when towing in 4th but not too bad.

It is losing oil from gearbox to transfer at about 1lt per 1500km, but I added the bypass hose and now the gearbox is staying full.

it makes me wonder though. how does the oil go up hill?

Or maybe the breather on the box is clogged and that was causing the box to pressurise and push oil through seal into transfer and now with bypass it kind of allows the main box to effectively use the transfer breather? (which I check is ok when servicing)

I think the main box breather is through the gear shift?

Mrs wants go on CSR later this year and I just wonder if I need to do box or should be ok for a while still???

I was going to get it all done until I put the bypass hose on (which I didn't expect to work and all the info I had read was oil going the other way eg transfer to box)

regards
Geoff 17

Geoff,

I first heard about the oil transferring "uphill" from the transfer to the gearbox and experienced the phenomenon quite a few models ago. It appears that as the tc and gb heat up the oil is pumped by the pressure in the tc overcoming the seal for the gb on the main shaft. As the oil level is higher in the gb as compared to the tc the lip of this seal is positioned to keep the oil in gb. Being a single lip seal as standard it doesn't take too long for the oil to overcome it. A double lip seal, as used in the later automatic Cruisers does prevent this, but of course to fit requires some dismantling which can be a bit onerous if all else is good.
This is where the hose between the filler plugs does the job of keeping the tc from running dry while the gb over fills. I'm not sure if it is just a matter of giving the oil a pathway to return or whether it is more about not allowing excessive pressure buildup. My opinion is that it probably is a bit of both.

I found out about the main shaft and tc gear spline wear when I noticed a fair amount of tailshaft backlash developing on whichever car I had at the time. Further investigation by removing the PTO cover on the side of the tc allowed me to determine that the backlash on the mainshaft was getting quite bad and that the nut in question was loose. Tightening the nut helped but of course couldn't cure the spline wear so it soon came loose again. A complete strip down and parts replacement was in order, so I have always kept an eye on the tension of this nut ever since. As you may have observed, this isn't too hard. Just a removal of the cover behind it.
The Cruiser that the mate had when we did the CSR trip many years ago required one of the modified longer spline tc input gears because the spline wear was getting way too bad to trust it for such a trip.
Whether the noise you are getting requires further checking is of course up to you. Personally I would get it checked out. I have seen a couple of the earlier transfer cases fail where the idler gear between the tc input and front/rear drive runs on a hardened shaft. From memory they had double row needle bearings but as this shaft is prevented from rotating it wears on one side only. Easy enough to change the shaft and bearings if caught early on. Caught early enough and usually the gear bearing surface is OK to go again. Catastrophic if left until it fails.

Cheers
Pop

Hi Pop

thanks again for the interesting information.

I probably was miss leading with my explanation re oil movement.

what mine was doing before the hose was loosing oil from the main box into the transfer.

But with the hose the levels of both stay reasonably normal, so either the oil is no longer moving from the boX to the T/case or if it is it is somehow moving uphill through the bypass hose back into the main G/box???

trouble being if full pull down then anything 1/2 worn probably should be replaced, but still may have 100K left in it????

Regards
Geoff 17

Geoff,

I haven't personally come across a situation where the oil is being dumped or pumped from the gb to the tc before. Usually the other way around.
Not to say it couldn't happen but to me the only scenarios where that would be the case would be if the seal between the two was either fitted the wrong way around, has failed completely or been left out.
In any of these I couldn't start to explain how the hose tc filler plug to gb filler plug mod could help by causing the oil to flow up the hose from tc to gb. With the tc oil overfilling the gb all the hose does is let the excess oil gravity feed back down the hose into the tc.

What you choose to replace if you go the full teardown is, as said, between you and your wallet. I guess it depends on what your long term plans are for the car.
IMHO they were a bloody good model, especially with the 12HT engine. Just getting a bit long in the tooth.

Cheers
Pop

Hi Pop

Yes I agree it makes little sense how the bypass hose can help the situation, only guess I have is if the breather of the main box which I think is part of the gear shift? is somehow clogged with gunk, then maybe when the bb heats up it pressurised and pushes oil past the seal??

can I replace this seal if only the transfer is pulled apart? or do you need to disassemble the gbox to replace this seal?

regards
Geoff 17

PS

also agree

great model

but yes getting too old I think?? trouble is it well set up and we make no money farming anymore so????

Geoff 17

Have heard of others doing this modification as well.

Most of the hydraulic suppliers have, or used to have kits for this. Pirtek, Enzed & others.

Fitted one to our HJ60......just need to make sure both the t'case seals aren't leaking, otherwise the system will empty the g'box. :-(

Bob

I did the "hose between the g/box and t/case filler plugs" many many years ago to a 1980 HJ45 Troopy. The same setup got transferred to a 1989 FJ73 (mid wheel base) and then on to the original g/box of my current HZJ75 when it had the H55F gearbox. I changed the H55F for a H150F when I did the engine upgrade.
I used a couple of banjo fittings with push on hose tails. From memory the hollow banjo bolts were 14 mm, or whatever size the original plugs are. Saved drilling and tapping the existing filler plugs and the whole hose and fitting assembly sits much closer to the casings so less chance of an errant stick ripping it off.

As Bob said, all the relevant hardware is available from any reputable hydraulic stockist.

If for some reason your hydraulic stockist gives you a blank look when you mention banjo fittings, go to your local fuel pump repair shop or failing that a Deutz diesel engine agent. They are infested with them.

Cheers
Pop

Cheers
Pop

Hi Bob Y

Thanks for your input.

I have heard that putting the bypass hose on is a risk if the seal fully lets go then even the hose wont save you.

How do you "make sure that both the t'case seals aren't leaking" as you suggest?

regards
Geoff 17

Unless the seal is damaged severely, Geoff, such as fencing wire caught in tail shaft, I've found that the TC seals generally start to "weep" first, and you have spots of oil splattered on inside of the chassis, front of rear axle housing and even small spots on rear tail gate. A small amount of hot oil often makes a big mess.

My current ute, an HDJ79, seems to favour the front TC output shaft seal.....have had to replace this twice in past 6 years. 2 wagons we had, an HJ60 and a HDJ80, both used to do rear seals. As long as either of these output seals aren't weeping/leaking then the bypass hose should continue to function.

Of course if you are checking fluid levels and TC is overfull, then it follows that this extra oil has come from the gearbox, and one would top off the g'box, and drain excess oil out of TC. Suppose this one way of keeping clean oil in the transmission. :-)

Bob

Hi again Bob Y

this old girl has only done around 200k since gearbox rebuild BUT is 12HT turbo and had done 60-70% of those km towing, at least 50% hard towing.

Not sure if I should be getting it done or there is some good life still in the box??

Regards
Geoff 17

Whether you get something done now is probably a decision between you and your wallet, Geoff. :-)

However, in light of the Cook's desire to travel the CSR, and the towing stats you mentioned, it might pay to get the spline and TC checked over beforehand. Better a few $$$$ now than a lot of them somewhere remote.

Pop would confirm but I think you can do a TC rebuild on the vehicle, so that might keep costs down. If oil from g'box is clean and has no expensive lumps in it, it might suffice as you say it was down 200K ago.

Then again, check the status of that nut and all might be good?

Bob

Hi Bob

I have read its ok o do T/case rebuild on vehical and I was mind of thinking I could put a kit in myself as from what I have read its seems reasonable straight forward.

But then I have also read where others have said its a bad idea to do a t/case rebuild on the vehical, so I am not sure!

Also if the gear to transfer is worn, this can only be replaced if the main gearbox is disassembled.


regards
Geoff 17

Geoff,

You can re-build your transfer case on the vehicle without taking the whole gearbox out. Not dead easy but certainly not rocket surgery.
Get a workshop manual and follow the instructions.

The gear that sits on the main shaft and drives the tc can certainly be replaced quite easily. I would source an after market longer splined gear as a replacement if you have any doubt about spline wear. No point putting a standard OEM gear onto a worn main shaft.
From memory Terrain Tamer did these and also bearing and seal kits.

Cheers
Pop