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#1 All Synchro Gearbox Leak Saga Continuation

Posted: Fri Sep 16, 2016 9:39 am
by politeperson
So after thinking that my oil leak was solved, it isnt.

I found the speedo drive was loose, but tightening it up has not cured the problem.

Oil dripping onto the centre exhaust boxes.

So, 15 minutes later, after the seats carpets, centre console, radio console and gearboxc cover are removed I am looking at this and this.
2016-09-15 15.44.48.jpg
2016-09-15 15.44.48.jpg (75.41 KiB) Viewed 2979 times
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2016-09-15 15.44.14.jpg (74.71 KiB) Viewed 2979 times
Oil appears to be coming around the selector rods and or the gasket at the rear of the cover.

I assume the selector rod "O" rings have failed and the whole top mechanism has to be dissembled to replace them. Anyone know?

The shift was nice. I cannot see any adjustments.

New o rings and top gasket ordered from SNG lets hope this cures it.

I have just sucked out the thin Redline oil and replaced it with thicker EP90 so that might help too.

Nice and easy to tip in in with the top off and the level indicator is easily visible.

#2 Re: All Synchro Gearbox Leak Saga Continuation

Posted: Fri Sep 16, 2016 2:59 pm
by Hugo
Breather?

#3 Re: All Synchro Gearbox Leak Saga Continuation

Posted: Sat Sep 17, 2016 4:10 pm
by politeperson
Well, I checked the breather, clear.

I changed the 3 three O rings and put the top back on with a new gasket.

The old rings were very brittle and hard.

On test I thought it was difficult to engage first and too easy to get reverse, so I increased the spring rate on the reverse lock our which provided a positive feel. This is just a matter of turning an external bolt at the end of the gearbox. Now it is perfect.

I can report after 50 miles I am gearbox leak free.

Also, I have recovered 3rd to 2nd gear syncromesh with the thicker oil. This is whens the box is cold and warm.

The gearbox snicks up and down like a new one. All for £2 of seals a gasket and some EP90.

I also discovered that I can remove and refit a hand brake caliper without dropping the rear end! That was a relief, I did however have to "use the force" and finally, I managed to adjust the sticking throttle by shortening a rod and adjustment.

So all in all a good afternoons work.

#4 Re: All Synchro Gearbox Leak Saga Continuation

Posted: Sun Sep 18, 2016 1:56 pm
by Hugo
I would never use anything other than ATF in a synchromesh gearbox. In the old days, EP (extreme pressure) and hypoid oils were completely different animals. Now they are the same, or at least they have managed to combine the properties of the two. The problem with hypoid oils is that they are designed for gears which slide against each other, which means they also allow the synchro rings to slip instead of biting. I run commercial vehicles with ZF boxes. One day a colleague with a Volvo coach phoned me in desperation to say his coach had just been serviced and now it was virtually undriveable as he couldn't change gear. It turned out the garage had changed the gearbox oil & replaced it with EP/Hypoid 90. I called ZF and they gave me the advice above. He changed the oil to ATF and it completely transformed the vehicle.