I have a small car (a Liege) which uses an 850 cc engine and a small 4 speed gearbox, the latter "not being known for its reliability". At Mallory Park racetrack during an endurance event the oil badly overheated and the gearchange became more tricky. The car eventually suffered a bad gear downchange (not me driving) which broke some teeth off the layshaft. To give you some idea of the pressure we put our little cars under, our team came 5th out of 26 teams involved and we beat a team driving a pair of 6 litre, 500 bhp cars; one a Cobra Replica and the other a Lola T70 replica.

I now wish to fit a small oil cooler to the gearbox using an electric pump. I have sourced the cooler and gear driven pump. I intend to use a thermostatic switch to control the pump.

Has anyone here relevant experience of this type of project and what are the pitfalls, if any?

I've found very scant information on the web and I've tried the search facility here with no success.

Thanks in advance for any advice, as long as it's not "use a better gearbox" because I'm hoping to keep the car original.

The oil is already thrashing around in there pretty well, so a finned sump/ sidecover/ whatever might be sufficiently effective.

If you're going to bother with a pump, it makes sense to also install a filter to catch pieces of the gearbox before they can cause a cascading failure.

I've heard this many times on hydraulic systems - but it doesn't work. If you do the calculations there is not enough heat rejection from metallic piping unless you are borderline. And consider that the air washing over the tranny is pre-heated by the radiator, engine and exhaust system.

I would strongly suggest adding the pump/cooler and using a good full synthetic oil. And as far as advice, the NASCAR teams all use differential oil coolers. Just Google "differential cooler" and you will get lots of hits.

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