A440 Tranny Issue (1 Viewer)

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May 16, 2011
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I recently took my hdj81 for a daytrip around some local backroads consisting of steep climbs on good logging roads. I was in D (high range) for the whole time. After climbing and decending 26 k's, halfway up a steep section (18% for 14k's) my A/T OIL TEMP warning light came on. I immediately stopped and noticed A/T fluid on the road for 50 feet behind me. Not like it had poured out, rather spurted (there may have been 1/2 litre on the road, although it was hard to tell with the drip/splash on the road)

I took a look and noticed the source of the leak was the observation plate on the bottom of the bell housing. The fluid was now just slightly dripping out, and i noticed steam comming from behind the plate also with a good pressure (like the steam from a boiling kettle). The steam stopped almost instantly, as did the leak.

I checked the A/T fluid level, it was low, but by no means empty and the warning light had gone off between the time i stopped and restarted the vehicle (maybe 3-5 mins). I let it cool for 15-20 mins and limped the 3-4 ks back downhill into town to buy some tranny fluid. She took about 1/2 lt - more or less, and the leak had stopped.

To get home I had to travel 26k's along roads with similar grades so i stocked up on fluid and went for it. I drove this time in L or 2 (still High range) with revs at 2000-2300 for all the uphill sections. I had no more problems - the warning light never came back on and the leak had stopped.

During this whole saga I never noticed any slipping of gears or clunking of transmission. Nor did I notice any engine oil in the tranny fluid or vice versa, the A/T fluid was still red, not too dirty and had a slight odour to it (not a strong burnt smell, rather a slightly hot fluid smell) and the engine temp didn't change from norm operating temp.

so here are my questions;

1) could it be possible that the overheating tranny created enough pressure for the fluid/steam to be pushed out the torque converter seal? If so does this mean my torque converter seal is now damaged, even though the leak stopped during the high load return journey home?

2) Could the overheating issue be soley due to climbing steep hills in too high a gear, or could there be another issue with my tranny?

I have owned the vehicle for 3 months and the mechanic who was selling it for the PO had just flushed the tranny. I have a little slop in my drivetrain, which i can only feel when i take my foot off the accelerator quickly while under load, or punch it too aggresively while under any speed. If i have a smooth foot I don't feel it - the tranny runs through the gears fine and never have i felt any slipping. I have climbed one very steep hill for 10-15k's (1800' vertical gain) and had no issues (although i was in L in low range)

i love my cruiser and know maintenance is of upmost importance, i also know the work involved, although still am learning how to do it!!

thanks in advance for the help
 
There have been some posts on the issue of the A440F temp warning light and overheating of the transmission which can cause damage; apparently the torque convertor design is inadequate as is the transmission cooling. Rodney at Wholesale Automatics in Australia should have a definite answer to your question and solutions, they rebuild and modify these transmissions. IIRC they have a new design torque convertor and recommend an oversize transmission cooler for at least part of the solution. Contact Rodney here:

Wholesale Automatic Transmissions
 
I don't have answers to your specific questions, but here's what I would do. (I have an A440F with Chev V8 and have gone through many trials and tribulations regarding the heat it generates.)

Most imporant, you need a gauge to moniter your tranny's fluid temperature. The A440F generates a ton of heat when the torque converter is not locked up.

Check out Wholesale Automatics web page for 'temp. gauge kit' and other info. on the A440F. I read somewhere once that 2nd gear in the A440F generates less heat than the other gears when the torque converter is not locked. I believe this to be true from my own experiences.

The ultimate solution for the A440F, provided by Wholesale Automatics again, although spendy, is to replace the torque converter and valve body. The torque converter is more efficient and the valve body allows lock-up in 3rd gear above a certain speed. I have added these 2 items to my '91 and the difference was substancial in terms of driveability and fluid temperatures.

So, it sounds like your fluid was coming from the tranny input shaft seal? I'd be concerned that it leaked. Was your tanny over filled with fluid? If you drop the tranny to replace that seal, that would be the time to install new torque converter and valve body if you were in a position to do so.

I also added an additional fan driven cooler for the the tranny fluid. It turns on and off automatically when the fluid reaches 180 or so; it' mounted under the passenger side floor board.
 
I recently took my hdj81 for a daytrip around some local backroads consisting of steep climbs on good logging roads. I was in D (high range) for the whole time...

Sounds like you learned from your mistake by downshifting on the return trip.
I had the same experience with the AT oil light on a recently completed long road trip, but didn't lose fluid. Our inline sixes just don't have the power to hold speed on steep inclines. With the tranny in drive, the low RPMs coupled with a low speed will eventually result in overheating. Better to drop the beast into 2 or 3, keep the RPMs up and resign yourself to an even slower speed uphill.
 
I don't have answers to your specific questions, but here's what I would do. (I have an A440F with Chev V8 and have gone through many trials and tribulations regarding the heat it generates.)

Most imporant, you need a gauge to moniter your tranny's fluid temperature. The A440F generates a ton of heat when the torque converter is not locked up.

Check out Wholesale Automatics web page for 'temp. gauge kit' and other info. on the A440F. I read somewhere once that 2nd gear in the A440F generates less heat than the other gears when the torque converter is not locked. I believe this to be true from my own experiences.

The ultimate solution for the A440F, provided by Wholesale Automatics again, although spendy, is to replace the torque converter and valve body. The torque converter is more efficient and the valve body allows lock-up in 3rd gear above a certain speed. I have added these 2 items to my '91 and the difference was substancial in terms of driveability and fluid temperatures.

So, it sounds like your fluid was coming from the tranny input shaft seal? I'd be concerned that it leaked. Was your tanny over filled with fluid? If you drop the tranny to replace that seal, that would be the time to install new torque converter and valve body if you were in a position to do so.

I also added an additional fan driven cooler for the the tranny fluid. It turns on and off automatically when the fluid reaches 180 or so; it' mounted under the passenger side floor board.

thanks mmuthart, could it be the torque converter seal rather than the input shaft? If so could the seal allow high pressure leaks while still being ok under normal operating temps - the leak seems to have stopped and i just drove the sea to sky highway in 30 deg temps!!

I am thinking about putting in a new valve body kit in and temp gauge - i believe you dont have to drop the tranny for these items??
 
honeybadger: that's correct, you don't have to drop the tranny to replace the valve body or install a transmission cooler. IMHO you might want to completely change out your ATF; apparently overheating can cause the ATF to degrade rapidly, or so I read, but be careful to not overfill it. FWIW.
 
thanks mmuthart, could it be the torque converter seal rather than the input shaft? If so could the seal allow high pressure leaks while still being ok under normal operating temps - the leak seems to have stopped and i just drove the sea to sky highway in 30 deg temps!!

I am thinking about putting in a new valve body kit in and temp gauge - i believe you dont have to drop the tranny for these items??

I'm struggling to remember, but I think there's only one seal and it's the input shaft seal.

Regarding pressure, this is my guess, but I don't think you can build high pressure in the system the tranny fluid runs through. The tranny has a vent hose and the dipstick is not really designed to hold pressure. Someone please correct me if I'm wrong. I've also never heard of an overheated auto tranny spewing fluid.

Correct, valve body is easily replaced with the transmission in place. Depending where you locate the fluid temp senser will determine whether lowering the tranny will make it easier. I believe Rodney's kit has the sensor right in the side of tranny where the fluid outputs on its way to the coolers up front. This looked to be a fairly difficutl spot to install with the tranny in place but doable. I put my sensor in a much more accessible place just after that hard output line turned to rubber.
 
...and i noticed steam comming from behind the plate also with a good pressure (like the steam from a boiling kettle). The steam stopped almost instantly, as did the leak.

if steam was coming from your trans then your ATF must have been contaminated.
your never going to be able to boil the ATF in your trans (you would melt every
seal and have a fire long before you got it hot enough) while the ATF will expand
as it's heated it would be minimal and not nearly enough to create pressure in what
is a "open" system. now this is pure speculation but if there was water in the
system as soon as it got to 212º it would boil "explosively" ( think water droped
in a frying pan) and may find it's way past a seal before it could force ATF up out
the dip stick...
 
Wondering if it actually was steam but coming from the rear of the engine or above the transmission, maybe from a rear heater hose??
 
thanks for all the replies!!

On further research Ive discovered that tranny fluid looses its viscosity when overheated to extemely high temperatures. The seals in a tranny are design to contain the fliud at its viscous state - if the fluid becomes too "watery or liquidy" (want for a better word) due to extreme temperatures the seals will not hold the fluid anymore.

One mechanic I spoke to has seen it where more than one seal leaked and the seals were not damaged!!

I have driven it all week (mountainous driving in hot temps) and have been monitoring for any leaks - there have been none :bounce:
I just hope the info ive recieved is correct!!
im not sure what the steam was (maybe fluid on the outside of the tranny??)

i will be getting a temp guage and cooler unit and change the fluid too!!
the valve body kit will have to wait till i find some cash:frown:

thanks again for all the help - more lessons on the fly
 
honeybadger: did you change out the overheated ATF?
 
not yet, but i will as soon as i can
would you recommend a flush, or just a change?
i had it flushed about 10,000 ks ago
 
Flushing a high mileage automatic trans can cause a whole new set of problems. I would drain and refill the pan at least 4 times with a short drive between each.
 
Some say drop the pan, clean it out, then do a complete fluid exchange. Done properly a complete fluid exchange using the current type of "flush" machines that use the transmissions pump to move the fluid shouldn't hurt your transmission (although I'm not a transmission expert). IME it's important to use the correct type and amount of ATF to completely replace the old fluid (14-16qts) and never use any additives or harsh solvent-type cleaners.
 
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A very non-invasive way to a more complete drain/refill (if you don't want to use a machine) is to simply drain the pan, replace the drain plug and let it sit for 24-48 hours. Another full pan will result and that can simply be drained again.
Take note of the total amount of fluid removed. During the refill, you will fill the pan and need to briefly run the motor to avoid a mess.
 
Puking Trans

I'm struggling to remember, but I think there's only one seal and it's the input shaft seal.

Regarding pressure, this is my guess, but I don't think you can build high pressure in the system the tranny fluid runs through. The tranny has a vent hose and the dipstick is not really designed to hold pressure. Someone please correct me if I'm wrong. I've also never heard of an overheated auto tranny spewing fluid.

Correct, valve body is easily replaced with the transmission in place. Depending where you locate the fluid temp senser will determine whether lowering the tranny will make it easier. I believe Rodney's kit has the sensor right in the side of tranny where the fluid outputs on its way to the coolers up front. This looked to be a fairly difficutl spot to install with the tranny in place but doable. I put my sensor in a much more accessible place just after that hard output line turned to rubber.

I have burnt up automatics resulting in trans fluid gushing out of the trans dipstick tube, a quart or more. Usually has to have a major issue to cause something like that, though, i.e. plugged vent, severe overheating, etc.)
 

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