FJ62 automatic tranny overheating (1 Viewer)

[helpcraft]

I've got an 88 FJ62 with an AT that I'm trying to keep cool.

I bought the truck a coupla years ago and it had an AAMCO rebuild in it. Climbing mountain passes--without any exceptional load, eg a trailer--would reliably cause the temp warning light to come on. Took it back to AAMCO several times and they could never find anything wrong. Eventually the tranny died a miserable death, and they rebuilt it under warranty. At that time, I had them install a tranny cooler.

Since then, the AT temp light has never come on. Until last weekend, when it lit up after climbing a hellacious pass in 90 degree weather under a fairly heavy load (4 passengers, big dog, cargo area and roof rack full of gear). BTW the engine has never had a cooling problem (new radiator, tstat, water pump, hoses, etc).

I know the FJ62 AT runs hot, but IMO with a cooler installed I should never see the warning light come on. Maybe I have a kinked hose, or a bad cooler installation? I don't trust AAMCO and am leaning toward having an indie shop check over their work.

AT owners--do you ever see the temp warning light come on? Any words of wisdom are appreciated.

 

[canyon62]

First off, welcome to the forum... always nice to have more people contributing.

You'll not get many replies to this post as this topic comes up again and again and again.

Use the search button on the 60 Forum for "tranny overheat" or "tranny filter" and you'll have plenty of info and opinions to read through.

I don't believe the trans light should ever come on 'normally' I think it kicks on at something like 300F, at which point you really don't want to continue pushing the trans. However, under the situation you describe, I would not be surpised to see that light. Many people seem to get about a year out of an AAMCO rebuild.

A couple of things of general concensus:
- AAMCO doesn't do a great job with these trannys. They aren't common and allthough reletively simple, most shops just don't seem to get it right.
- Rodney from OZ provides a very well respected replacement A440 with a few tweaks for much better performance. http://www.automatictransmission.com.au/default.asp
- Running synthetic trans fluid seems to help
- make sure the trans filter screen is clean
- run a large cooler: https://forum.ih8mud.com/showthread.php?t=76962&highlight=trans+cooler+install

 

[helpcraft]

Awesome, thanks for the info Scott! I just discovered this board--what a great resource for a newbie TLC owner.

One addt'l question: any idea how hot the tranny has to be before triggering the warning light?

 

[canyon62]

I guessed in the previous post, but was pretty close...

https://forum.ih8mud.com/showpost.php?p=1316327&postcount=8

 

[azaussie]

First off, welcome to the forum... always nice to have more people contributing.

You'll not get many replies to this post as this topic comes up again and again and again.

Use the search button on the 60 Forum for "tranny overheat" or "tranny filter" and you'll have plenty of info and opinions to read through.

I don't believe the trans light should ever come on 'normally' I think it kicks on at something like 300F, at which point you really don't want to continue pushing the trans. However, under the situation you describe, I would not be surpised to see that light. Many people seem to get about a year out of an AAMCO rebuild.

A couple of things of general concensus:
- AAMCO doesn't do a great job with these trannys. They aren't common and allthough reletively simple, most shops just don't seem to get it right.
- Rodney from OZ provides a very well respected replacement A440 with a few tweaks for much better performance. http://www.automatictransmission.com.au/default.asp
- Running synthetic trans fluid seems to help
- make sure the trans filter screen is clean
- run a large cooler: https://forum.ih8mud.com/showthread.php?t=76962&highlight=trans+cooler+install

Scott - great quick recap (with links) for the FJ62 auto tranny.



Canyon, the only thing I would add is that several folks have swapped the auto for a 5 speed manual (search for H55F + Dunbar.).

 

[helpcraft]

Based on reading the other threads, my cheapest route is:

• flush the tranny
• fill it with synthetic
• clean the filter screen
• install a gauge; anyone have pictures of an installation to share?

Finally, I found this note from another thread interesting:

"If your stock temp light comes on you should pull over immediatly! It comes on at 230 IIRC which is really hot. Put the transmission in neutral or drive and let the truck idle. Even better, run some water over your aftermarket cooler to help bring down the temps. If the light is coming on you might also want to slow down, but not below 54 MPH because that's where the torque converter locks up (which brings temps down)."​

The last sentence encourages me to adjust my driving style--I'm sure that I was below 54mph during my climb over the pass. Of course, keeping a fully loaded FJ62 above that speed is a bit of a challenge

I suppose I can also reduce heat by manually placing the tranny in gear 2 or 3 while climbing, instead of letting it automatically shift between gears, right?

Thanks again!

 

[euclid]

To your last question: no. The torque converter only locks up in D on a stock A440. If you drop down to 3rd the torque converter unlocks which = LOTS OF HEAT! Heat is the worst thing for an automatic.

If you want to drop some coin you can get the extreme valve body from austrailia. It keeps the torque converter locked up in 3rd and 4th (Drive) gear so that you can drop down to 3rd to pull those long hills without risking damage to your transmission.

Your list of to do's is a good one.

How big is the cooler? Might go bigger.

In the end it sounds normal. High heat is going to follow a heavy load.

Look in the FAQ's at the top of this forum. There is a section in there with other links for Automatic stuff.

 

[PortFJ62]

I had a tranny cooler installed and have never seen the light come on again. 2 years ago.

 

[cruiser88]

i have never seen my light come on. dump the old cooler i bet it has a restriction buy a bigger cooler its not costly at all

 

[meris]

my cooler - install used mitusbishi pajero oil cooler to HJ60 ATF cooler