After only some short road miles (c200 km) when British Classic Cars had the vehicle, it was apparent the formerly leak free gearbox had developed some drips.

When I rebuild the gearbox, I used Loctite gasket sealant in front and behind all of the gaskets. On the whole this has worked and the gearbox has only 2 leaks from gaskets and one from a seal. (more on that next post)

The sealant on the gasket behind the transfer case cover plate has failed and theres a nasty drip making a mess on my drive. I assume that, at the time of installation, there was oil contaminating one of the surfaces so the sealant wasn’t actually bonded to the gearbox and / or cover.

To cure this, the oil was drained from the transfer box, cover plate removed and everything given a good clean prior to refitting with a new gasket and NO sealant this time.

Cold chisel and adjustable spanner used to remove the drain plug. There’s no special tool for this as far as I know.


…and let the 2.5 ltr of oil drain out. Enough time for a cup of tea.


Next, the 8 flange bolts are removed…


… and with a sharp tap with a soft faced mallet, the cover plate is removed revealing the transfer box internals.


On cleaning up the face of the cover plate, I found quite a deep score mark. Could be that the oil was coming through this groove?


To eliminate the risk, I polished it out as best I could with some wet and dry


The mating surface of the transfer case had all the sealant compound removed and cleaned back to bare metal


There is a chance the oil was dripping from the drain plug, so some PTFE tape was used on the threads. I’ve used this many time on Land Rover threads and it works quite well as a simple “belt and braces” to cure oil leaks…. Especially where gravity is involved.  PTFE stands for polytetrafluoroethylene. Quite a mouthful. I much prefer…. “Plumbers Tape Fixes Everything”… which it does  🙂


Drain plug, PTFE tape and crush washer


Drain plug screwed home in the cover plate.


New quality gasket. The cover plate instructions suggest adding a bead of sealant. Having not being able to create a 100% oil tight seal with the gearbox on the bench, I doubt if I’m going to achieve one with the residual runs of oil contaminating the transfer case mating surface.


Everything back in place… I’ll fill it with oil after the next job.