Gearbox Cooling - Defender

By way of comparison, the xfer case high temperature warning switch in the V8 Discos comes on at 145 deg C, yet the TD5 Discos don't have the switch.

Some LT77's and R380's had oil coolers. The adaptor bolts to the left hand side of the gear case.

Most are simply a pipe that runs up to the front and back. The Wolf's have a larger cooler.

I fitted an adaptor from an LT77 to my R380 and installed an oil cooler up front.

The gearbox will love you if you fit an oil cooler, but I doubt you will benefit from much reduction in temp inside the cab.

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Originally Posted by Xtreme

Has anyone been successful in getting the gearbox of their Defender Xtreme to run a bit cooler and not generate so much heat around the seat box. Is there an oil that runs cooler or is ducting some air onto it the answer. I'd be interested in any suggestions.
I have had this problem in my previous 200Tdi Defender and now in the Xtreme and with summer rapidly approaching I figure it's about time I did something about it.

Roger

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Use a telescopic shock absorber as an oil pump. Mount an extra shockie on an axle and use it as a piston pump. Install the top and bottom sections with some tubes and fittings through an oil radiator. I had two of these on my Monaro GTS 350 in 1970 to cool the Muncie and the diff. (370bhp at the rollers)
Perhaps, nowadays, oils, and electric pumps have improved and this type of system would be an easy hook-up.

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Originally Posted by Brian Hjelm

Use a telescopic shock absorber as an oil pump. Mount an extra shockie on an axle and use it as a piston pump. Install the top and bottom sections with some tubes and fittings through an oil radiator. I had two of these on my Monaro GTS 350 in 1970 to cool the Muncie and the diff. (370bhp at the rollers)
Perhaps, nowadays, oils, and electric pumps have improved and this type of system would be an easy hook-up.

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ahh, not needed Brian as the R380 has an internal pump, and TD5's have a t/stat housing/adapter and cooler (ok, it's only a pipe) as John has outlined above.

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Originally Posted by Xtreme

Thanks for all the comments guys but it seems that I need to clarify a few points.

• The heating problem is continuous but varies depending on the ambient temperature.
• It is most noticable on the seat box in the vicinity of the gearbox.
• It occurs with and without CDL engaged but is most noticible (and annoying) when on the blacktop.
• The handbrake is not binding.
• The Xtreme does have an oil cooler.
• It occurred in exactly the same way on my 200 Tdi Defender.

So it seems from your comments that it is simply the heat from the exhaust pipe and motor. However I feel that this much heat cannot be good for the gear box, hence my desire to rectify the situation.

Maybe I just need to do more river crossings to cool the g'box!

Roger

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All the waste heat from the engine comes back under the vehicle - and as hot air rises it will concentrate at the highest point and concentrate there - in the centre of the seat box and the transmission tunnel. The heat will not damage the transmission until it gets hot enough to break down the oil or damage the seals, which is pretty hot. Maybe what you need is better insulation on the seat box and transmission tunnel.
John

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Originally Posted by JDNSW

<snip> Maybe what you need is better insulation on the seat box and transmission tunnel.
John

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which is exactly what a few of the Seth Efricans have done on a couple of other forums (fora ??)

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Originally Posted by rick130

ahh, not needed Brian as the R380 has an internal pump, and TD5's have a t/stat housing/adapter and cooler (ok, it's only a pipe) as John has outlined above.

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OK. Not aware these things now have pumps and coolers. If the problem is from under bonnet hot air, why not have a look at a White Road Boss from circa 1979-80. These had ducts in the fibreglass bonnet to take air from intakes alongside the radiator grille and directed a flow of air down the firewall to keep the drivers thongs from melting. The Cat and Cummins engines used, designed for LH drive countries, had all the hot bits on the RH side. We were once shown a thong that had a hex melted into it from a bolt head that held the engine cover to the floor inside the cab. The fix worked. So maybe some flexible ducting from the front of the car to the top of the transmission may give relief.

Thanks to everyone for your comments/suggestions.

I think that the way to go is to duct from cool air from the front of the vehicle, incorporating some form of valve in the ducting so I can enjoy the free heating during winter. Insulation around seat box would be an option but fiddley to get right and it doesn't address the source of the problem as well as ducting. Also, I have a fair length of 45mm dia aluminium tubing stashed under the house that will do the job nicely.

Thanks again for everyones input.

Roger

Thread not dead!

I'm going to try plumbing some hose for cool air to the top of the transmission tunnel as suggested. Out of interest I'll do a before and after measure of the temps and if anyones interested I'll post it.

Has anyone done this or have any tips or tricks?

Any suggestions where the best place to mount the inlet would be?

I've been thinking likewise Matt.......run a metre or so of 75 mm flexible rubber duct with the front of the duct above the crossmember under the transmission against the chassis rail on the passenger side then running back and into the void between the seat boxes. The idea being that the duct would pick up enough clean air to blow into the void and remove the air pocket (if that is what is causing the problem).

I have some 90 upvc pipe and fittings but was a little concerned that if it came off at speed it might do some damage either to the Defender or those following.

If that works then a mandrel bent metal tube might provide a more robust and permanent solution.

Seeing that you are just down the road we should put our heads together on this one.