A440F overheating - help and ideas? (1 Viewer)

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C

CanuckMariner

Joined
Feb 13, 2007
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I have had consistent overheating of my trani in my 90 HZJ73 on longer trips and especially those long hill climbs and loooong steady grades. Burnt out one trani already and now the replacement (used) is doing the same thing. Had my rad inspected and tested and they can't find anything wrong. ATF filter cleaned many times, ATF fluid checked hot and cold adn has plenty, no transfer oil going to trani, good flow from pump, system has been flushed, clutch fan cheked and workking great, any ideas what the ailment could be? I am running 5700 lbs with all my gear and just me and up to 6500lbs maxed with a passenger and gear/food etc. for long camping trips. Could it be a weight thing?:idea:

Added a turbo (T3/4 hybrid) and larger exhaust (2.5") recently to help get up those long climbs. Running 5-7 psi mostly with possibility to 12-14 for the hill climbs. EGTs between 700-800F mostly and up to 1000F on hill climbs. NO black smoke at all. Could it be running too lean?

Also, engine is overheating occasionally, suspect a common problem with rad/tranni cooler even though can't find anything wrong?

:confused: I read all postings on this forum re A440 tranis and only common answer was to replace rad. I am having my rad rebuilt from single to triple core lines (whatever they are called), supposed to be best for cooling out there and removing old tranni cooler replacing with aux tranni cooler, hope this solves problems.

Any help is most appreciated!
 
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how's the cowling and seal around the rad. This is something that is often overlooked and causes problems. I'm assuming there is nothing in front of the rad (ie, lights, winch, etc)
 
Silly question but you are checking ATF level with the engine running right? I only ask because I've seen it before.
 
I suspect you already have looked, but there is lots of info on the A440F in the 60 and 80 sections. My knowledge is based on the experiences of guys with 62s, not sure if there would be any differences from your HZJ73's, aside from the torque convertor.

The 62 got the A440F, as well as the first 2 years of the 80 (albeit with an aux tranny cooler a common factory option, and *perhaps* a more efficient torque convertor than in the 62). The TC's are not very efficient, and produce a lot of heat when not locked up, on the flip side, I understand flow to the cooler to be cut dramatically when lock up is engaged. Long climbs often require downshifting to 3rd, which leads to higher heat generation (TC free), along with the higher demand the engine puts on the cooling system at the same time. The ATF temp indicator light, from my understanding, comes on at a pretty high temp, when you are likely to be damaging the fluid already....

Upgrades that are common in 62s are installing a proper ATF temp gauge to monitor temps BEFORE you hit damaging levels, and aux cooler downstream from the in-rad cooler, and for some spendy types, an upgraded valve-body from Wholesale Automatics in Australia (available in NA from Pacesetter Products in Whitehorse). This valve body provides for lock-up of the TC in 3rd gear (additionally to 4th) when ever your output speed is above the cut off (~80km/h), and is supposed to improve flow through the cooler circuit along with pressure to the clutches, yada yada yada.... I just ordered one of the valve bodies today, and hope to install it along with a cooler in a month or 2.

I'm sure there are more Australians who frequent the 70 section than the 60 section, and can give some more feedback on Wholesale's products.... Rodney at Wholesale seems to be pretty good at replying informatively to e-mail enquiries, but keep in mind that he has an obvious interest in selling the products too.

HTH
 
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Overheating Engine

Have you checked/serviced/replaced your clutch fan?

After 18 years it's not going to be working like it should.
 
maximBJ70 said:
how's the cowling and seal around the rad. This is something that is often overlooked and causes problems. I'm assuming there is nothing in front of the rad (ie, lights, winch, etc)
Click to expand...

Rad has been thoroughly checked by specialty rad shop with no problems found.

Yes there are lights and a winch (in ARB bumper) but rad has lots of air hitting it at 90 km/hr (55 mph).
 
CanuckMariner said:
Clutch fan working great!
Click to expand...

Good. I had a similar overheating problem with my HZ . . . just on those long up hills and the major problem was the clutch fan.

Added a couple of tubes of clutch fan oil and it's now much better but the temp spring is going and I will need to get a new clutch fan assembly if I want to do towing, etc.

After 17 years the fluid is toast.
 
a buddy of mine had an idea for a fix on a clutch fan missing its temp spring, put a screw into the clutch fan it won't matter about fluid and might move more air.
 
Those rad can be funny trust me there but i added a huge aftermarket cooler on my 62 ,bought a new rad. and but in a extra fan for those slow HOT crawls and it does wonders:cheers:
 
FWIW, last night I decided that I am going to buy a digital oven thermometer, and rig up a ghetto ATF temp "gauge" ($20 vs. whatever for a proper one). I'd like to compare temps before and after the new valvebody and cooler, and if it holds up, I will likely keep it hooked up to monitor things when the truck is working hard.
 
RockDoc said:
FWIW, last night I decided that I am going to buy a digital oven thermometer, and rig up a ghetto ATF temp "gauge" ($20 vs. whatever for a proper one). I'd like to compare temps before and after the new valvebody and cooler, and if it holds up, I will likely keep it hooked up to monitor things when the truck is working hard.
Click to expand...
Cool:D....i need to get something rigged up myself
 
as we discussed in person, an aux cooler is a must in your case and a tranny temp gauge installed.
 
Like I mentioned to you on messenger, add the aux cooler - that type I sent you the link to - doesn't need alot of air passing over it - more of a heat sync. Get a tranny temp guage, add an aux fan if you think your engine is going to overheat again. Are you using the A/C when pulling up the big hills?? That taxes everything as well.

My truck is 5600 pounds with the steel box on it, I have an upright 8274 winch, intercooler, a/c condensor and a s***ty repaired rad - never overheats with 1000 or more pounds in the back. (new rad going in next week and a new aluminum box install this weekend - should free up 1000 pounds on my truck). Running 12 pounds with the intercooler and conservative fuel adjustment.

If you really want to be safe put a manual tranny in it and call it a day - but still add an aux fan (but I don't think cruisers ever should need one - I suspect there is something wrong with your cooling system).

How's your rad cap? does liquid boil in the resevoir when hot? You say the clutch fan is good - is it new ?? reconditioned? If not buy a new one so the guessing is over with. How's your thermostat - installed correctly? What oil you running in the hot conditions?

If I remember correctly I think you said that you downshifted manualy to 3rd gear for the hill climbs - that heats up your tranny. Also, that tranny was a liottle different than your original - did you get it set up properly so that it shifts correctly?

Don't run your truck at 12-14 pounds without an intercooler, you don't need to get up a hill faster - think about longevity. When you want to learn about the proper set up of a turbo check out what the boys in OZ are doing with theirs and what they recommend - alot more informative and much more experience than anyone on this board (aside from the guys in OZ who might frequent this board). I go to outerlimits4x4 and 4wd monthly forums. Your main concern is not driving your truck in canada, you are driving it in very hot regions that are very taxing on vehicles - you need to be set up for that environment.

Good luck!
 
lshobie said:
Like I mentioned to you on messenger, add the aux cooler - that type I sent you the link to - doesn't need alot of air passing over it - more of a heat sync. Get a tranny temp guage, add an aux fan if you think your engine is going to overheat again. Are you using the A/C when pulling up the big hills?? That taxes everything as well.

My truck is 5600 pounds with the steel box on it, I have an upright 8274 winch, intercooler, a/c condensor and a s***ty repaired rad - never overheats with 1000 or more pounds in the back. (new rad going in next week and a new aluminum box install this weekend - should free up 1000 pounds on my truck). Running 12 pounds with the intercooler and conservative fuel adjustment.

If you really want to be safe put a manual tranny in it and call it a day - but still add an aux fan (but I don't think cruisers ever should need one - I suspect there is something wrong with your cooling system).

How's your rad cap? does liquid boil in the resevoir when hot? You say the clutch fan is good - is it new ?? reconditioned? If not buy a new one so the guessing is over with. How's your thermostat - installed correctly? What oil you running in the hot conditions?

If I remember correctly I think you said that you downshifted manualy to 3rd gear for the hill climbs - that heats up your tranny. Also, that tranny was a liottle different than your original - did you get it set up properly so that it shifts correctly?

Don't run your truck at 12-14 pounds without an intercooler, you don't need to get up a hill faster - think about longevity. When you want to learn about the proper set up of a turbo check out what the boys in OZ are doing with theirs and what they recommend - alot more informative and much more experience than anyone on this board (aside from the guys in OZ who might frequent this board). I go to outerlimits4x4 and 4wd monthly forums. Your main concern is not driving your truck in canada, you are driving it in very hot regions that are very taxing on vehicles - you need to be set up for that environment.

Good luck!
Click to expand...

With the research I have done on OZ forums and Toyota Japan I have found that it is the A440F that is the problem not my rad or my boost or my aux tranni cooler or or my clutch fan anything else, it is the A440F. Rodney in Oz and Toyota Japan set me straight and got a fix for me. I have a HD TC and Extreme duty VB now and all is fine. thanks!
 
CanuckMariner said:
With the research I have done on OZ forums and Toyota Japan I have found that it is the A440F that is the problem not my rad or my boost or my aux tranni cooler or or my clutch fan anything else, it is the A440F. Rodney in Oz and Toyota Japan set me straight and got a fix for me. I have a HD TC and Extreme duty VB now and all is fine. thanks!
Click to expand...

Interesting. What are your seat of the pants changes that you notice in driving with both the HD TC and Extreme Duty VB? Don't discount adding an external cooler like lshobie was suggesting. When I was talking with Rodney about Petra's A440 is was on his list of suggestions too. On recommendation we got the Tru-cooler. I think it was the 4543: Automatic transmission cooler guide and installation. Are you running synthetic ATF as well?

hth's

gb
 
Big loads, hot desert weather, problematic auto tranny = install tranny cooler where I come from.
 
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