Author Topic: Gearbox oil leak from driveshaft  (Read 5161 times)

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Offline Lotuswins

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Re: Gearbox oil leak from driveshaft
« Reply #15 on: Monday,June 04, 2018, 07:48:47 PM »
Hi Stuart,

I just had my box apart, changing it for a newer one.  From your pictures, at least of the new banks nut and seal set, the seal appears to be in too far?  It may not be where you ended up with, but note that the outer seal is a dirt seal, and it rides on the inner part of the yoke.  The inner seal rides on the center of the spacer.

Also, how are you setting the axle/yoke shims?  are you getting the assembly tight so the yoke cannot shear off the roll pin?  I usually shim them so the pin drives in just a little harder than with no spacers so I know it isn't allowing any play and the yoke is tight against the spacer and won't damage the pin.

Also, when I disassembled this newer 365 box, it had the bottom of the nuts and the o-rings siliconed in.  It had only 18k miles on it so either it was a virgin or had been sealed up by a dealer.  Either way, I too used a 1/8 silicone bead around the outer, back of the bearing race, against the inner threads of the housing, and screwed in the nut into the silicone.  Then used a small amount on the axle groove where the o-ring will sit, sliding the o-ring onto the axle, and then a small amount on the inner lip of the spacer where the o-ring sets.  I was able to press the spacer on by hand up against the bearing.  I let the assembly sit overnight and installed the axles, etc. the next day.  So far, knock on wood, it hasn't leaked a drop in 300 miles.   I tried the loctite thread sealant, but had such a time removing the nuts the next time I vowed to try something different.   

Jerry Rude
4005R


Stuleslie

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Re: Gearbox oil leak from driveshaft
« Reply #16 on: Monday,June 04, 2018, 11:27:12 PM »
Hi Jerry, yes your right the new nut and seal in the top left of picture from Banks is too far in. This is how it comes, the back edge of the seal is flush with the back of the nut. After extensive measuring I pressed the seal into the nut by 2.5 mm.
I have ensured the axle/yolk is shimmed up tight.
I will look into using the sealer as you mentioned when I reassemble the box.
The strange thing is that I have had no trouble with the left hand side, it has been perfect since I changed the seal.
Stuart

Stuleslie

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Re: Gearbox oil leak from driveshaft
« Reply #17 on: Friday,June 08, 2018, 12:06:55 PM »
Problem solved :trophy:
I’ve got a dirty big b&*#;y hole in the casing!
I had to take the gearbox out to see if there was something wrong with the diff bearings. I took the bellhousing off and as I was looking at the bearing and saw light through the hole above the righthand bearing in pic 1. It turns out to be a hole for a speedo inductive sensor which senses the dog toothed gear attached to the diff casing in pic2. Evidently it is quite rare and is usually blocked off. There are many holes in the box casing but they are all blind ended (except my one). I plugged the hole with a 3D printed bung with a screw flange. Pic 3
Perhaps I should get the dummy award of the month but unless you take the bellhousing off you would never know that the hole was not blanked off.
FYI I made a bracket under the balance point of the gearbox and attached it by four M8 bolts into the box and bolted the bracket to my trolley jack. I could then pump up the box level to the engine and push it into the clutch plate single handed in pic 4 (sorry slightly out of focus)
Road test perfect, not a drip, I’m a happy bunny. :BEER3:

Online BDA

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Re: Gearbox oil leak from driveshaft
« Reply #18 on: Friday,June 08, 2018, 01:00:04 PM »
I wouldn't feel too badly about it, Stuleslie. It's not something you would expect and a quick look through the NG manual, I didn't notice anything about it. I've certainly been caught by a lot more obvious stuff than that, but admittedly, that is a low bar.

I'm glad you finally solved the problem and everything is working!

Offline Bainford

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Re: Gearbox oil leak from driveshaft
« Reply #19 on: Monday,June 11, 2018, 11:40:56 AM »
Well, what may have seemed dire a couple of days ago is now a simple issue with a straight forward fix. Sounds like a win to me. Glad you got to the bottom of things.
The Twin Cam plays the symphony whilst my right foot conducts the orchestra. At 3800 rpm the Mad Pipe Organ joins in.

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Stuleslie

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Re: Gearbox oil leak from driveshaft
« Reply #20 on: Wednesday,June 13, 2018, 07:18:45 AM »
Thanks Guys for all you help and sympathy  :))
I wonder how many gearboxes like mine are out there. The tag label states it was a NG1 but when you look at the diff. it has four planar gears like a NG3 box. :confused:
Stuart

Offline StephenH

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Re: Gearbox oil leak from driveshaft
« Reply #21 on: Sunday,November 11, 2018, 11:57:02 PM »
On the subject of leaking output shafts....

What size are the original O-rings?
There is mention of 21mm id x 29mm od x 4mm thick earlier in the thread, but that appears to have been a best efforts guess.

Thanks in advance :)
Stephen
54/1690 1969 S2

Stuleslie

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Re: Gearbox oil leak from driveshaft
« Reply #22 on: Monday,November 12, 2018, 08:45:14 AM »
Hi Stephan, that is exactly the size I fitted in my box. The 4mm thickness does require a bit of compression to lineup the roll pin holes. It was not difficult with the chassis on stands I just just slowly jacked up the wheel and the holes aligned. There is a company in the UK that can supply o-rings in any combination of id, od, and thickness at minimal quantities, so if you need their address I can look them up for you.
Stuart

Offline StephenH

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Re: Gearbox oil leak from driveshaft
« Reply #23 on: Monday,November 12, 2018, 05:56:34 PM »
Thanks, I've got some that should be close enough so saves going looking for more.

Anyone got strong feelings on using/not using a smear of additional sealant on the spacer or splines?
At this stage I'm not planning to, but it's been mentioned to me by the local Alpine guy.
Stephen
54/1690 1969 S2

Offline jbcollier

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Re: Gearbox oil leak from driveshaft
« Reply #24 on: Monday,November 12, 2018, 08:26:36 PM »
If everything is super clean, it won't hurt.  Don't use a sealer that sets otherwise it will be heck if you have to get the spacer out again.

Offline StephenH

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Re: Gearbox oil leak from driveshaft
« Reply #25 on: Wednesday,November 14, 2018, 02:34:03 PM »
I chose to keep clear of sealant for now as it isn't a big job to pull the shafts and add if required.
Only had short 1 heat cycle/run but no leaking so far.

Have I mentioned how much I dislike changing uni joints?
Not the assembly, it's the removing the old ones that bugs me ;-)
Stephen
54/1690 1969 S2

Offline 4129R

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Re: Gearbox oil leak from driveshaft
« Reply #26 on: Wednesday,August 18, 2021, 09:29:58 AM »
I think I can match the diversity of the gearbox oil leak through the driveshafts described above.

I bought 4376R and 4688R in pieces in a 40ft container via a dealer in Chicago who died, the whole lot went to a dealer in Houston, who also died, his widow sold them to an enthusiast in Louisiana who decided it was beyond him, so 4376R, 4688R and a whole load of other stuff, the good, the bad, and the ugly, was shipped in a 40ft container via New Orleans and Southampton to me.

I have completed 4688R which I am keeping, and I am finishing off 4376R at the moment. I put the gearbox in, drained and filled it with oil, and oil poured out of the diff output holes, both sides.

I thought putting the driveshafts in would cure the leak so set about getting the shaft splines lined up to bash in the roll pins. I check the holes are lined up with a 5mm drill. If that goes through and there is no inward play when I take the drill out, I know the shimming is correct.

The shimming was awful, so I went on eBay and bought loads of shims. £3.69 for 10. Cheap. I will have 10 in all the sizes please.

The shims arrived, and it was time to add more shims to get the play out before driving in the roll pins.

I thought I would see how big the gap was by undoing the big castellated ring thingy, and it was f'ing huge. 10mm. Something is wrong, all I could see was a rubber O ring.

I then undid the castellated ring thingy on another gearbox and saw a splined spacer covering the O ring. This spacer was missing on both sides on the gearbox which fitted 4376R.

Luckily the container came with a spare 4 speed gearbox, so I went to get the spacers out by undoing the castellated rings. They were f'ing tight. I have the special tool from Banks for undoing them, a 1 1/16" ring spanner to put on the end , a big hammer, so I started undoing the ring thingies. After about 1/2 a turn, they are normally easy to undo. This one was very tight, I put heaps of pressure on the ring spanner, bashed the spanner with the big 2kg hammer, and "Ouch". The spanner fell off and my head went straight down on the the selector rod on the end of the gearbox, and then my head started leaking. "Ouch" was not enough, time to go and clean up the wound.

I stopped the bleeding by pressure on toilet tissue on the wound. I summoned the courage to look in the mirror, took the tissue off and there is a Mercedes 3 spoke star right between my eyes. I looks like some sniper has assassinated me. Time to fit an Elastoplast.

Anyway, I removed all the shims, fitted one splined spacer, mastic on the ring thingy, tighten to the same place marked with a dot from a centre punch, fit the lock tab,  line up the splines and the holes in the driveshaft, and with zero shims, the holes align exactly. Drive in the roll pin, and all looks fine. 

So the oil leaking out from the diff output shafts was because the 10mm splined spacer was missing so the oil seal in the castellated ring thingy had nothing the seal against.

Tomorrow, the other side.

I now have to go down the pub with a plaster on my forehead right between my eyes. That will take some explaining. Taliban assassination attempt maybe.

Offline TurboFource

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Re: Gearbox oil leak from driveshaft
« Reply #27 on: Wednesday,August 18, 2021, 12:24:11 PM »
I had to laugh when you said "your head was leaking".....been there done that unfortunately ... :o (leaking body parts)
The more I do the more I find I need to do....remember your ABC’s …anything but chinesium!

Offline Sandyman

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Re: Gearbox oil leak from driveshaft
« Reply #28 on: Wednesday,August 18, 2021, 12:51:46 PM »
Thanks for the laugh. Hope you can fix the leak. I am glad I have a red car. It hides all the leaking I have done.

Offline 4129R

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Re: Gearbox oil leak from driveshaft
« Reply #29 on: Wednesday,August 18, 2021, 01:46:20 PM »
Thanks for the laugh. Hope you can fix the leak. I am glad I have a red car. It hides all the leaking I have done.

Head leaked in the pub. Landlord gave me a blue Elastoplast. Do they make plasters with targets on? I feel like a target yet to be hit with the blue plaster central just above my eyebrows.

I won't know about the gearbox oil leak until the car is driveable in about 3 weeks.