A/T transmission oil temp warning

[Bat21]

Took the parents out today, it is their 52nd wedding anniversary. Had to use a small caravan step for mum to climb in

Took them around some lovely back roads and tracks in Shropshire.

A couple of times the A/T transmission oil temp warning came on while traveling up very slow steep hills.

Is this normal? It was only about 12 degrees today... what is the oil temp going to be like when it is 40 degrees and traveling through sand in Morocco later this year

 

[Andrew Prince]

Nope, Paul, that doesn't sound right! As you say, that doesn't bode for well hot conditions and heavy loads

Stating the obvious but presumably your ATF level is ok and the fluid is in reasonable condition?
It is worth having a quick check that the hoses to the rad are ok and there is no sign of ATF in coolant and vice versa.
Bit of a left field one but check the earth on the alternator as a bad earth can cause the dash lights to flicker - unlikely but easier to check than the oil cooler internals.

Looks like you might need to try Jon's oil temp guage to confirm that your ATF is getting too hot...

Were you chugging up at fairly low revs? The advice seems to be to drop to a lower gear if the ATF temp rises too much as the higher engine revs will pump the ATF through the cooler faster. This only gets round the problem a bit, it's not addressing the cause.

Good luck!

Cheers,

 

[Bat21]

Radiator was replaced last year. At the same time I drained and replaced the AT fluid.

I checked the level when I got home and it was fine, I also smelt the dipstick and it doesn't smell burnt.

There were some very steep hills and I guess we never got over 15mph while going up them, in hind sight I should have put the box in L instead of letting it change up to 2nd/3rd.

I also have 35" tyres which probably doesn't help?

 

[Jon Wildsmith]

Low ish speed (little air flow) working hard for a while with 35's it's easy to imagine it overheating. Simplest way to check it's for real when it happens is to point an IR thermometer at the oil pan and see what it says, or switch the engine off and listen underneath to see if you can hear the oil boiling If it's genuinely overheating, by the time that light comes on the oil is already extremely hot and you need to stop and let it cool and each time it happens the fluid degrades and the gearbox components are severely stressed A decent aux cooler is a good idea, but maybe something bigger than the Kenlowe ones. IMO a temp gauge is essential on 80's so you can see what's going on before it's a problem.

 

[Julian Voelcker]

Paul,

What colour is the oil? Also what ATF did you put in it last time.

If you are unsure of the history, the first thing I would do is to drop the pan - I have come across people with problems because at some point in the car's history the oil got severely cooked resulting in sludge blocking the filter - their oil looked fine. Once you have removed the sump you should remove the filter and give it a really good clean - you will need some decent clutch and brake cleaner and an airline.

When you refill the box use a fully synthetic Dexron III ATF.

As others say, with the 35s do consider fitting an oil cooler. The key thing is to fit it so the oil flows from the box, through the cooler in the bottom of the rad and then through your extra oil cooler - from memory it needs to be tapped in to the pipe coming out on the passenger side of the rad.

 

[Bat21]

Thanks Julian, the oil is Red with only the slightest Brown tinge to it, it doesn't smell 'burnt'.

I fitted a new rad about 5 months ago and drained out what ATF I could through the drain plug then. I replaced it with Morriss' Liquimatic ATF (see link), is that ATF ok, or should I be looking at a different type?

It sounds like an ATF shower is on the cards for me is there a gasket between the pan and the gear box?

 

[Jon Wildsmith]

It sounds like an ATF shower is on the cards for me is there a gasket between the pan and the gear box?

There should be a cork gasket but some are RTV'd

 

[Julian Voelcker]

It sounds like an ATF shower is on the cards for me is there a gasket between the pan and the gear box?

There should be a cork gasket but some are RTV'd

Interestingly I think it is the other way around

Toyota don't list a cork gasket and the manual recommends RTV, yet many rebuilders seem to be able to source cork ones.

 

[Jon Wildsmith]

I don't think I've ever looked for a part number so maybe you're right Julian but the red car pan which was OEM has a gasket and the green car pan which had been rebuilt was RTV! Not taken the pan off any others though so it must have been a quirk.

 

[pugwash]

There were some very steep hills and I guess we never got over 15mph while going up them, in hind sight I should have put the box in L instead of letting it change up to 2nd/3rd.

I also have 35" tyres which probably doesn't help?

yep there's the problem- you are working the torque converter incredibly hard in this circumstances- low revs, really forcing the torque converter to multiply the torque of the engine to turn the gearbox. Steep hills and 35" tyres only make it much much harder for the gearbox.

nothing likely to be wrong with the gearbox itself, driver error in this case. Next time go for low range, or go up the steep hills quicker.

 

[Bat21]

yep there's the problem- you are working the torque converter incredibly hard in this circumstances- low revs, really forcing the torque converter to multiply the torque of the engine to turn the gearbox. Steep hills and 35" tyres only make it much much harder for the gearbox.

nothing likely to be wrong with the gearbox itself, driver error in this case. Next time go for low range, or go up the steep hills quicker.

Thanks PugW, it is looking more like the 'Nut' that connects the drivers seat to the steering wheel that is the problem

Makes perfect sense what you are saying and, while talking to someone today, he said exactly the same as you have done.

I think I still might drop the pan off the box and check/clean the pickup filter as Julian suggests.