ATF overheating in the Alps - Help

[Pumpy]

HDJ81 1992 12v been having issues with the ATF overheating, I'm presuming it's because I've got 315's fitted and pushing quite hard to keep up with a D4 and an RRS up very steep switchback roads in the Alps with ambient temps at 27-32 C

First time I almost overheated the truck, stopped just before it went in the red, could hear the water boiling. 2nd time I stopped as soon as the warning light came on. From then on took it real careful in low range over the next Alp, now stopped at campsite on Italian side.

ATF is still pink, doesn't smell burnt, not lost any - not lost any water either, no sign of water on dipstick or oil in water.

Any advice would be apreciated, cheers lads

 

[grantw]

That bites quite a bit.

My first thought would be the thermo fan. Is it kicking in and kicking in hard? An easy way to test is to try and move it just after you've switched it when you have been over heating. It should be at the very worse quite difficult to move.

Also worth checking of course is adequate airflow to the radiator, with no leaves, spot lights etc blocking airpath.

I have also seen mods on an 80 where the bonnet it held open slightly by quite a few washes or a longer bolt.

 

[grantw]

Some good advice here too.

http://www.horizonsunlimited.com/hu...-vehicle/overheating-toyota-landcruiser-24710

 

[Lorin]

I had the same when driving switchbacks. I also have the extreme valve body but temps still exceeded 120C on even a pretty short set of switchbacks (I have a transmission temp gauge so can see the temps). Only way I could mange it on the trip was by using low range. Unless the gearbox can get into lockup the temps rise very quickly. Switching off OD will enable the box to lockup in third I think but doesn't help with the slower stuff.

From what I've read, if your temps have hit the 150C needed to trigger the ATF light (it turns off at 120C) and you're not running fully synthetic, you will need to change the fluid. Wholesale autos recommend Castrol Transmax Z but make sure you're sitting down when you see the price. A full flush and fluid change on mine just used 20 litres!

Do your temps come down quickly once the gearbox locks up? Checking the fan is engaging properly is probably a good idea but I reckon these boxes do get hot pretty easily.

Next up for me is large auxiliary ATF cooler and lockup switch.

 

[Pumpy]

Thanks grant, we like the idea to test the viscous fan, we did try to see if it was working correctly but engine had cooled down, so that's one avenue to look at further tomorrow when engine is up to temp.

It's funny as yesterday we did some similar roads with no issues, but having thought about it we were in low range the whole time - the ratios are so bad with 315's I had to put it in low range to get off the ferry ramp, keeping in high must have had an effect - I'll get the boy racers to slow down a bit!

I'll be taking it much easier in low tomorrow. Also just cleaned the front of the rad with a hose, there were a few seeds and a bit of dust in there but nothing major.

 

[Pumpy]

Cheers Lorin - no overdrive on the HDJ81, thanks for advice re low range and helping me to see a better picture of the issue - does low range and keeping in specific gear keep the box locked? Think that's maybe the way forward.

Could be tempted by an aft cooler right now, but we'll see how we get on for the rest of the trip

 

[froggy Steve]

Not the same truck, but fitted an Aux trans cooler on my 95, and a new rad, just to be safe. temps are a good 10 degrees lower at all times .

 

[David]

Are you on tarmac or stone tracks when it gets hot, we pretty much drove all the stone tracks in low box tbh
Our trucks seemed to run hotter on the motorways going than they ever did on the tracks

 

[TonyP]

Fixed the thread title for you..

 

[StarCruiser]

I managed to find an ATF and PS oil cooler from a jag, something like this one, on eBay.
https://www.ebay.co.uk/itm/191917947480

 

[StarCruiser]

I managed to find an ATF and PS oil cooler from a jag, something like this one, on eBay.
https://www.ebay.co.uk/itm/191917947480

 

[StarCruiser]

I'm pretty sure I need to do my viscous fan as I can stop it when it's warm and rotating. I found this out by accident BTW

 

[David]

You could try taking the 3 big spotlights off Mal fitted to it, that would improve the airflow a lot

 

[StarCruiser]

I've often thought spotlights in front of radiator grilles were a bad idea. Do you have a winch and/or intercooler? Also is there clear passage between the AC (if you have it) condenser and the radiator?

 

[David]

I've often thought spotlights in front of radiator grilles were a bad idea. Do you have a winch and/or intercooler? Also is there clear passage between the AC (if you have it) condenser and the radiator?

It has a factory fitted winch and a intercooler, or it did when it was mine, I often thought the spotlights blocked to much go the grill up tbh

 

[StarCruiser]

The intercooler will likely raise the temp going into the rad and I would guess the winch will mask some of the airflow from lower down. It sounds like there's several factors involved here, or to put it another way, several areas where things could be improved.

 

[chapel gate]

Ive often wondered why a vehicle that is run in some of the hottest places on the planet seems to suffer some overheating issues.

Sorry mate, i can see im not helping here..

 

[Dave2000]

The viscous coupling is normally the culprit. Very difficult to tell if it is working correctly. I use an all electric system but that is for another day, tends to spark people off. Auto's here overheat the trans as well when loaded and in the mountains. You have to be mega careful with the hose as you can cause more trouble than you realise. The only way to do it properly is to remove the fan cowl and blow out with an air line from the engine side. If you use a hose from the front it tends to push the rubbish in tighter than a ducks arse under water. Also the grass seeds take on water and swell up, not only making them more difficult to remove but they block the air flow even more.

A trans cooler is always a good idea and there are a couple of alternatives, the first is to do away with the stock system. This also prevents oil to coolant contamination in the event of a radiator failure. Another method is to fit an additional cooler, my preference is to fit it in the line before going into the OE radiator. My only reason for that is the OE system is supposed to help the oil warm as well in colder climates, so if the additional cooler is too effective during say winter, then the flow through the rad will bring the oil nearer to the OE expected temperature.

Regards

Dave

 

[Pumpy]

Cheers for advice lads, lorins post helped me see it might be normal ish, I found sticking it in low range and keeping revs below 2k best, had no further issues since I stopped pushing it trying to keep up with the D4 on the Tarmac switchbacks, 25mph is quick enough up them anyway!

Got no diff centre lock lights at all now, not sure if it's going in or not, only tried it once on the trip, should be ok tho, I'll have a look at it when I get back.

 

[clivehorridge]

I'm pretty sure I need to do my viscous fan as I can stop it when it's warm and rotating. I found this out by accident BTW

Not necessarily so Rich, IMO.

My fan rarely kicks in, but it does when it needs to.

Last weekend, it was 35 C with no wind at all, very hot. I was in low 3rd on a stone track hauling up a long steep incline at a steady 2,600 rpm. Just before the top, the fan kicked in (made me jump).

It's a real roar on my 80, sounds like a Harrier going over. But it only operates under extreme conditions. I don't think I've ever had it kick in on the road under normal driving.

I don't tow, so that may trigger it for some, in hot weather.