Auto tranny cooler

[bob h]

One for the knowledgeable gurus. Been thinking about using an air conditioner evaporator [the one at the front of the radiator] as an oil cooler for the aoto tranny. My thoughts are that it would/should be large enough to provide adequate cooling when doing heavy work. My concerns are that not enough oil flow, thus causing overheating in the tranny, and alternatively too much cooling therefore tranny not at optium temperature. A good idea or not? Thanks, Bob

[bee utey]

An a/c condenser should easily do the flow and pressure. Overcooling? You could arrange a temp gauge/monitor in the trans and bypass the cooler with a solenoid valve when it's running cold.

[blitz]

I've been wondering what would be the best way to go - P38 cooler to expensive, aftermarket coolers to small.

Bob thats a brilliant idea they are cheap and would work a treat

[PhilipA]

The pipe should be run through the radiator first so that it is not overcooled.
However I wonder if you are not killing an ant with a sledgehammer as if you use synthetic oil it can withstand heat without breakdown.
I guess if you are towing a BIG van it could be useful, but mine has never worried with my 600KG camper even in 40+.
Regards Philip A

[goldey]

Philip

An observation that may / may not be helpful.

I installed a P38 cooler on my auto after it imploded a couple of years ago, never had an overheating problem since, including towing our camper and lots of low range and high range sand 4wding.

To my point though, we have just recently been upgrading our camper (ie two deep cycle batteries and running 12V and 240V circuits, and a toolbox for the a frame) so I took it to a weighbridge to get weighed (are you sitting down?). The trailer with camper top, internal drawers, kitchen and basically packed ready to go except for gas, water and kids bikes came in at 1080kg.

Incidentally, it also measured a 120kg downball weight and the Disco came in at 2230kg (with a full fuel tank, but precious little else).

Cheers

Goldey

[Lotz-A-Landies]

4 Tonne trailer, ZF auto and Mt Victoria, gee I wish I had a bigger trans cooler.

However what I would suggest, before anything else is to install some form of external monitoring, like a temp sensor and guage. This way you can see if the trans fluid temp is getting up, before it is a problem and drive accordingly.

My solution (although I haven't fitted it yet) is to merely run a second of the same element used in the RRc and early Discos and I have doubled the cooling.

[d2dave]

I did this on an old Holden years ago and it worked well. I had converted it from manual to auto and instead of getting a new radiator I used an air con condenser.

Dave.

[Slunnie]

One for the knowledgeable gurus. Been thinking about using an air conditioner evaporator [the one at the front of the radiator] as an oil cooler for the aoto tranny. My thoughts are that it would/should be large enough to provide adequate cooling when doing heavy work. My concerns are that not enough oil flow, thus causing overheating in the tranny, and alternatively too much cooling therefore tranny not at optium temperature. A good idea or not? Thanks, Bob
I'm not sure that an AC unit would be rated for 120psi or so.

I've been there, tried that and spent it all - ZF's run significantly more line pressure during lockup than other autos.

I wouldnt fit a regular ATF or AC cooler. I'd go straight to an ATF cooler with pirtek type multi-barbed pressure fittings or not bother at all. All of the ATF coolers that LR use on the ZF's have pressure fittings rather than the normal slip on or single barb fittings.

[LOVEMYRANGIE]

My solution (although I haven't fitted it yet) is to merely run a second of the same element used in the RRc and early Discos and I have doubled the cooling.

Yep, and run them parallel, not series. Will drop the flowrate and increase the cooling efficiency.

Either that or look at an Eaton 18025 cooler used on Roadranger gearboxes.

Cheers

Andrew

[bee utey]

I'm not sure that an AC unit would be rated for 120psi or so.
AC pressures regularly top 200psi. If you can adapt suitable hose fittings to a multi-path condenser I can't see why it wouldn't work. Proper crimped AC hose fittings should do it providing your cooler hose is compatible.

[PhilipA]

To my point though, we have just recently been upgrading our camper (ie two deep cycle batteries and running 12V and 240V circuits, and a toolbox for the a frame) so I took it to a weighbridge to get weighed (are you sitting down?). The trailer with camper top, internal drawers, kitchen and basically packed ready to go except for gas, water and kids bikes came in at 1080kg.



My 1997 Camp'o'matic Getaway came with a tare of 600Kg and a GVM of 750.
I then removed the Toyota split rims and 750.16 tyres and milled off the brake drums , calculating the saving at 54 KG when using RRC mags and 205x16s.

So I am pretty comfortable that mine is less than 750Kg even with a full tank and 2 full jerries.
However I must admit that I haven't weighed it yet. It's only been 4 years!
It has no fridge, no batteries, and a couple of alloy tool boxes which don't weigh much.
Just on overheating transmissions.
I have never had the trans light come on in my car even when driving hard at Stockton. I always shift to low ratio as with the higher revs there is less slippage in the torque converter and therefore less heat. As you know an auto will always try to go to the highest gear and I also often manually control gears in sand to be in a lower gear .
When attacking a BIG sandhill I will hold it in second to get revs right up and let it run down on the hill without usually having to use full throttle in a high gear. This way you can also modulate your speed at the crest much better to avoid too much air. I always found even in Saudi that too many revs were very preferable to too few.

Regards Philip A

[dagz]

I have a disco2 td5, now with p38 trans cooler. I tow a large van (basestation by jayco) if you know it. Max ATM is 2700kg. I initially was towing well and have done a few miles but was overheating the trans on long uphill hauls. After the auto cooler was upgraded one of the lines blew while towing and dumped all the fluid. Big tow bill and another repair for new trans fluid lines, and then the inevitable......... the trans started to over rev between gear changes. I have now had a low kay change over unit installed and yet to see what is to happen with the whole deal.........i suppose i have the standard fittings on the fluid lines, who do i see about changing them.. and what else can i do, i notice a temp gauge is suggested in this post........temp gauge and multi barbed couplings???????? will alleviate any future dramas or atleast help me to avoid them.

[Blknight.aus]

go the AC cooler route it'll do the job nicely. save the lines from the AC system you pull the cooler from and somewhere like pirtek will be able to match the fittings OR adapt the hoses across.

[Hamish71]

My P38 cooler cost $50 from a wrecker (admittedly, I spent $250 with him that day so got a good price), and then another $50 for a radiator place to flush it, and then $10 to get a welder to take the fittings off my original cooler, and weld them onto the p38 cooler. Then about 3 hrs of my time fabbing up some mounts to make it fit on my bigger uintercooler.

Then, original hoses used, bolt on.