Automatic transmission overheating (1 Viewer)

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V

Vanisljoe

Joined
Mar 19, 2009
Threads
42
Messages
272
Location
Nanaimo, BC
Hello,

I have a 91 HDJ81

I recently did a drive towards the top of Mt. Washington but had to turn around after the ATF warning light kept going on

Seems to be good now. No longer getting hot. I guess it straightened itself out...
 
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A properly functioning 442 with a properly installed aux. cooler shouldn't overheat like that. I would try to get the trans. healthy before I spent $1,200 on a valve body... Maybe it is time to drop the pan and have a look inside? there should be little magnets on the bottom of the pan you could inspect for filings... simple- is your cooler/rad dirty or plugged with mud?
 
ForealBoreal said:
time for an extreme valve body and a trans temp gauge.
Click to expand...

That won't help much if you are below 60km/h... I don't know how big that grade is but I have heard that if you keep the revs high it won't heat up nearly as much as will keep its self relatively cool.

I know that just normal hills around here I can hit over 200f in short sections... I am running an external cooler in series with the factory rad cooler and an extreme VB.

It's amazing how fast the temp will drop if I can get it up to 60k on a hill in third.

Another option if its a really steep hill and you are not afraid of going slow is pet her in low rage and get her locked up around 30... This is assuming you did the Pin7 mod.... Just don't forget to plug your CDL back in, right Sailor :flipoff2:
 
Also check the clutch fan if the viscous fluid is low, with the engine off, if it spins freely with your hand then it is low, it should be fairly stiff to spin.
 
My AT Temp issues (discussed recently in this forum) were caused predominantly by mud between my Radiator and AC Condenser. I also had the fan clutch re-oiled. Haven't hauled any big hills since but no heat issues going up the cut after the Iron Workers Bridge in North Van. I'll be doing Duffey Lake Rd next weekend so that will be a good comparison. Like Sailor mentioned, hopefully it's something simple like dirt/mud.
 
I was doing drives similar to the OP when it happened. Up to Cypress or Seymour or something. I regularly see 225 or so on drives up the Coq, but my EGTs usually get a bit high before I'm worried about the trans temp.
 
i would get tcs to rework your converter and lower the stall a bit (650) before doing the valve body .in fact the v/b is the last thing i would do .i myself have had nothing but troubles with shutter and heat issues .mind you i am putting a little extra out of the motor . i did a lot of fumbling and research .then bit the bullit and tried the t/c build ,now the shutter is almost gone with full fuel and my temps came down 30+ degrees and it locks up at 57 km. mind you, you have to really watch the egts with the lower stall speeds. i have heard benz automatics is the place to take it to if you are going the rebuild route. i took mine to them and they said that mine was in good shape and high temps 250 260 was exceptable (i have never seen the 302 degree light come on ,on any of my landcruisers).the only thing they and others came up with is that i was pushing the limits of the hp that the tranny was designed for . i also am running tandem b&m tranny coolers from the start,new rad ,no a/c condenser.
 
my at temp light came on twice last year. once on duffy lake road in 3rd around 60 with 5 people in the car. no power to pull in 4th gear. second time on a hill on logging road, 7 people inside, 2nd gear 4wd hi, around 20km/h. I am also running extra tranny cooler, did flush the oil for the 2nd time now. Filter was cleaned the first time. next step maybe EVB...?
 
wrongway around said:
i did a lot of fumbling and research .then bit the bullit and tried the t/c build ,now the shutter is almost gone with full fuel and my temps came down 30+ degrees and it locks up at 57 km. ...
Click to expand...

Impressive. After having my A440F light come on a couple times on steep grades during a 3000+ mile road trip two summers ago, I bought a new low stall TC from Level 10. www.levelten.com It was around $700 USD. The salesman says that the Saudi's run these TC's without extra coolers in the deserts over there. Maybe just sales talk, who knows. I also took the opportunity to go with synthetic fluid since it's hard to get a good flush with the original TC in place. I'm pleased with the performance, but haven't put it to the steep grade test yet because that entails leaving town.
 
I just got a A440F converter done by a place in Arizona.

http://www.roadrunnerconverters.com/contact.htm

They are doing a full rebuild, dropping the stall to 1600RPM installing a carbon fibre HD lock up and welding all the fins for high torque strength.

Costing me $150 + $40 shipping each way.

They came highly recommended by a few people on Mud and 4btswaps.
 
I have read numerous people bitch about the overpriced and overrated Extreme trans that rodney in Aus.
Glad there are stuff for a fraction of the cost of an EVB here in north america.
 
ForealBoreal said:
I have read numerous people bitch about the overpriced and overrated Extreme trans that rodney in Aus.
Glad there are stuff for a fraction of the cost of an EVB here in north america.
Click to expand...

I have not found a replacement for a EVB yet, I'm planing on modding the VB in the project A440f I'm playing with now. Plan to increase line pressurised and flow through the cooler and maybe make it lock up in 3rd as well.

Other mods will be adding steels and frictions to the 1st and OD clutch packs 1-2 added for each pack.
 
i hope you can do it all for cheaper than evb. that would be sweet.
your still planning on the isuzu right?
 
ForealBoreal said:
i hope you can do it all for cheaper than evb. that would be sweet.
your still planning on the isuzu right?
Click to expand...

Yeah, the mods I'm planing require nothing but time and $10 in washers and a drill bit. Im not going to mess with the 3rd gear lock up but may be able to make it work. Im more interested in added flow on the cooler circuit and added line pressure. The extra clutches in 1st and OD clutch pack are mainly for added power handling the torque will be in the 450-500ft/lb range at 1800rpm ;)

I think with the mods planned it should handle it fine the only variable is the guy turning the wrenches.....me.

Yes still planing on an Isuzu diesel.
 
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