Transfer box sump

Ed Evans tries a new type of transfer box sump on his Series III, and weighs up the benefits

How to fit a sump to a Series I, II and III

THE main problem we in the UK have with the Series transfer box is perpetual oil leaks from the pressed steel cover on the bottom of the unit. Impact damage and thermal expansion combined with low rigidity of the cover plate means leakage past the gasket between the plate and the transfer box casing is common. Fitting a new cover, re-jointing and tightening the securing nuts in careful sequence may cure the problem, but I’ve just fitted a new product to my own Series III which I hope will solve the problem for good.

Wootz, in Tucson, Arizona, sent a sample of their transfer box sump which replaces the pressed steel plate. The Wootz sump is cast aluminium, so should have a similar expansion rate to the transfer case it’s bolted to. It looks tough enough to withstand off-road impact, and has a thick flange that shouldn’t distort after bolting up.

It’s also designed to assist cooling by allowing for a larger oil capacity and by dissipating heat through its cast cooling fins. Excess heat isn’t a known problem here in the UK, but in warmer climes, covering long distances, especially with

heavy loads, transmission oil temperature can be a concern (see separate panel ‘Wootz Series IIA’). As a bonus, it looks a lovely piece of kit when you take a look under the vehicle.

I fitted the sample sump to my own Series III to check the quality and fit of the kit and, in the long term, to see if the flange stays leak tight. Here’s what’s involved.

Class kit

The Wootz kit includes the cast

1

aluminium large capacity sump with cooling fins, a thick gasket, new fixing bolts, a magnetic sump plug and clear instructions.

Drip point

The standard closing plate on the 2 transfer box usually weeps a little oil from the gasket at the lower end, despite careful fitting.

A good sign

After cleaning around the drain

3 plug, the oil is drained into a clean receptacle. This oil is like new, a sign all is well in the transfer box.

Nuts and washers

While the oil continues to drain, 4

the 7/16 AF nuts and washers are removed. If re-using the old pan, they would be released in sequence to prevent distortion.

Uncovered

The cover pan will need light

5

persuasion with the end of a screwdriver to separate it from the gasket, ensuring the transfer box joint face is not marked.

Remove studs

The flange studs need to be

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removed because the new sump will be held by bolts. First, two nuts are wound onto the stud, and tightened together.

Extracting

The nuts grip the thread so, using 7 a spanner only on the nut nearest the flange, the stud can be screwed out. Use two spanners to remove the nuts.

Flange prep

With the studs out, it’s now easier 8 to scrape off the old gasket. Ensure it is completely removed, then wipe the area with solvent to remove oil.

Flatting

The flange face is cleaned off with 9 emery cloth backed by a flat file. This ensures a clean level surface and highlights any high spots or depressions.

Oiled up

After cleaning debris away with a 10 cloth, EP90 oil is spread over the flange face with a finger to help the new gasket come away easily next time.

Ready to fit

New gasket positioned on the sump 11 after lightly greasing the flange to hold the gasket in place during assembly (and help it release in the future).

Initial attachment

For ease, the sump is offered up and 12 one bolt fitted to hold it. It can then be positioned, checking the holes in the flanges and gasket align.