blowing tranny fluid
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blowing tranny fluid
I have a '93 E-250, and am assuming it's the same set up as an F-250. 351EFI and E4OD. After driving 45 minutes at 65mph, the tranny will blow fluid and I'll leave a cloud of smoke for a quarter mile as it burns on the exhaust. First time this happened I was pulling a trailer. Now it happens every time I drive over 60. I can drive for hours at 55-60 without a problem. Last time it was 40* outside. The torque converter locks at 45mph, so I don't think it's a slippage problem.
I'm guessing the blow out is due to a heating problem, but it's cold here and it still happens. Also, wouldn't the tranny actually run cooler after lock up? When it blows, I can loose up to a quart of fluid. Fluid doesn't smell burned. After a few minutes, I can continue and if I stay around 55, there's no problem. I'm open to any thoughts on this, and where do I begin to solve the problem.
I'm guessing the blow out is due to a heating problem, but it's cold here and it still happens. Also, wouldn't the tranny actually run cooler after lock up? When it blows, I can loose up to a quart of fluid. Fluid doesn't smell burned. After a few minutes, I can continue and if I stay around 55, there's no problem. I'm open to any thoughts on this, and where do I begin to solve the problem.
Cargo Master
Joined: Jun 2003
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From: Somewhere Saskatchewan
Noop.
In lockup and towing is when temperature rises.
The fluid expands and pukes out the first available orifice.
You should never tow in OD position.
A very large external cooler is mandatory too.
The fluid expands and pukes out the first available orifice.
You should never tow in OD position.
A very large external cooler is mandatory too.
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Lockup will cool the trans, not heat it. The advice above about never towing in overdrive is bad advice. Ignore it.
There is something wrong. If the trans is overfilled it will do this. If the cooler or cooler line is plugged or restricted it will overheat the trans and do this, too.
The faster the engine turns the faster the trans pump turns, so there is more flow to the cooler. If the cooler is restriced it will be worse at higher speeds where there is more flow.
There is a test to see if the line or cooler is plugged.
Remove the cooler line where it attaches near the rear of the trans. Point the line into a bucket. Start the engine, then switch the line into another bucket for exactly 15 seconds. You should have at least 1 quart in the second bucket. If not, either a line is plugged or the pump is going.
There is something wrong. If the trans is overfilled it will do this. If the cooler or cooler line is plugged or restricted it will overheat the trans and do this, too.
The faster the engine turns the faster the trans pump turns, so there is more flow to the cooler. If the cooler is restriced it will be worse at higher speeds where there is more flow.
There is a test to see if the line or cooler is plugged.
Remove the cooler line where it attaches near the rear of the trans. Point the line into a bucket. Start the engine, then switch the line into another bucket for exactly 15 seconds. You should have at least 1 quart in the second bucket. If not, either a line is plugged or the pump is going.
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This is what I was thinking all along. What's been bothering me, is it didn't happen in the summer, but has happened 3 times this winter. Once when it was 15* outside. I suspected cooling problems, but the fluid doesn't seem that hot. or smell burned. I'll do a test and also backflush the cooler.
Cargo Master
Joined: Jun 2003
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From: Somewhere Saskatchewan
Ok then.
Lets see if we can pick your theory apart.
Towing a trailer in OD position.
On level ground, no head wind. Works good.
Push into a head wind with a good grade in the road.
The engine gets a load placed on it and tells the transmission and counteracts by unlocking the convertor.
Ok for awhile so the convertor locks up again.
This scenario can carry on for many miles depending on the terrain and distance.
Every time the convertor locks and unlocks the transmission temperature will rise. Each time the convertor locks and unlocks some clutch material will wear off.
Now where does this material end up?
Yup, the cooler.
So now you not only have a hot transmission but the cooling capacity is greatly reduced. Which adds to more heat. Excess heat causes the fluid to expand. Which quite often will result in fluid being puked out of the breather tube or even the front seal.
I have read many many owners manuals and each one states do not tow in overdrive.
Sure your cooler could be restricted. The question is why?
Contamination from clutch material. That's why.
The solution is simple.
Do not tow in overdrive.
Towing a trailer in OD position.
On level ground, no head wind. Works good.
Push into a head wind with a good grade in the road.
The engine gets a load placed on it and tells the transmission and counteracts by unlocking the convertor.
Ok for awhile so the convertor locks up again.
This scenario can carry on for many miles depending on the terrain and distance.
Every time the convertor locks and unlocks the transmission temperature will rise. Each time the convertor locks and unlocks some clutch material will wear off.
Now where does this material end up?
Yup, the cooler.
So now you not only have a hot transmission but the cooling capacity is greatly reduced. Which adds to more heat. Excess heat causes the fluid to expand. Which quite often will result in fluid being puked out of the breather tube or even the front seal.
I have read many many owners manuals and each one states do not tow in overdrive.
Sure your cooler could be restricted. The question is why?
Contamination from clutch material. That's why.
The solution is simple.
Do not tow in overdrive.
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Originally Posted by stuart1
I have read many many owners manuals and each one states do not tow in overdrive.
I tow 9100 pounds in overdrive, and if I'm over 55 MPH it stays in overdrive and the torque converter stays locked.
Your theory is blown apart!
Cargo Master
Joined: Jun 2003
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From: Somewhere Saskatchewan
Well now senor.
I just happen to own a 2002 Ford. My manual states do not tow in overdrive.
That plus the fact that I have been a transmission rebuilder for the better part of 40 years and a Journeyman technician for 47.
I have seen thousands of transmissions overheated and blow fluid due to towing in overdrive.
An added external cooler is mandatory and very often part of an exchange rebuilt transmission.
There are many internal modifications that can be done at the time of a rebuild. One of which is to increase lubrication and cooler flow.
Quite often convertor clutch disengagement is very soft and can go undetected.
Stock convertor clutches apply and are held with too low oil pressure.
There are modifications for this as well.
Common sense obviously enters the picture.
http://www.axiom.com/atc/archive/com...S-FB-06-04.pdf
Here is an article about various repairs and cooler flow.
That plus the fact that I have been a transmission rebuilder for the better part of 40 years and a Journeyman technician for 47.
I have seen thousands of transmissions overheated and blow fluid due to towing in overdrive.
An added external cooler is mandatory and very often part of an exchange rebuilt transmission.
There are many internal modifications that can be done at the time of a rebuild. One of which is to increase lubrication and cooler flow.
Quite often convertor clutch disengagement is very soft and can go undetected.
Stock convertor clutches apply and are held with too low oil pressure.
There are modifications for this as well.
Common sense obviously enters the picture.
http://www.axiom.com/atc/archive/com...S-FB-06-04.pdf
Here is an article about various repairs and cooler flow.
Last edited by stuart1; Mar 8, 2005 at 08:24 AM. Reason: Clarification.
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when I do the test. I should look for volume from the pump...1 qt in about 15 seconds. What kind of pressure should I expect? Should I be able to shoot this across the room, or will there be little or no back pressure. A bad pump can have volume if there is no restriction, but still may not be able to push fluid through a cooler, or produce enough pressure to keep the converter locked. I have the tools to put a guage on this, if it's necessary.
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Originally Posted by stuart1
I just happen to own a 2002 Ford. My manual states do not tow in overdrive.
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ok, you guys skipped over my last question. I should also have added that 'it seems' like the transmission is 'slamming' into 2nd gear. The transition to 3 & od are hardly noticeable. I'm not heavy on the gas. It's like it revs for a fraction of a sec before hitting 2nd.
Back to the pressure thing. Is there a pressure test plug on the shift linkage side, and if so, what should it test at? (A friend said 1000psi!) What should the pressure be on the cooler side, if I test while everything is still hooked up?(20? 40? 60?)
Back to the pressure thing. Is there a pressure test plug on the shift linkage side, and if so, what should it test at? (A friend said 1000psi!) What should the pressure be on the cooler side, if I test while everything is still hooked up?(20? 40? 60?)
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ok, you guys skipped over my last question. I should also have added that 'it seems' like the transmission is 'slamming' into 2nd gear. The transition to 3 & od are hardly noticeable. I'm not heavy on the gas. It's like it revs for a fraction of a sec before hitting 2nd.
Back to the pressure thing. Is there a pressure test plug on the shift linkage side, and if so, what should it test at? (A friend said 1000psi!) What should the pressure be on the cooler side, if I test while everything is still hooked up?(20? 40? 60?)
Back to the pressure thing. Is there a pressure test plug on the shift linkage side, and if so, what should it test at? (A friend said 1000psi!) What should the pressure be on the cooler side, if I test while everything is still hooked up?(20? 40? 60?)
Cargo Master
Joined: Jun 2003
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From: Somewhere Saskatchewan
okee dokee.
Your statement.
"You haven't read any Ford manuals. They state you can tow in overdrive unless the transmission frequently shifts in and out of overdrive."
My proof.
http://members.troublecodes.net/stua...ers-manual.JPG
"You haven't read any Ford manuals. They state you can tow in overdrive unless the transmission frequently shifts in and out of overdrive."
My proof.
http://members.troublecodes.net/stua...ers-manual.JPG
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It looks like it proves both of our points. Just above what you're reading is this statement:
"Drive (OD OFF) is useful whenever driving conditions (i.e., city traffic, hilly terrain, etc.) cause the transmission to excessivley shift between overdrive and drive."
As for towing in drive, it says to shift to drive up and down steep hills. It does not say to tow in drive all the time.
As for tunruh and his pressure test, there is a pressure test port on the driver's side of the transmission. 1000 PSI would be neat! That should be enough pressure to blow transmission parts through the side of your garage, not to mention any people nearby.
I don't have a shop manual handy. It does list normal pressure under most operating conditions.
"Drive (OD OFF) is useful whenever driving conditions (i.e., city traffic, hilly terrain, etc.) cause the transmission to excessivley shift between overdrive and drive."
As for towing in drive, it says to shift to drive up and down steep hills. It does not say to tow in drive all the time.
As for tunruh and his pressure test, there is a pressure test port on the driver's side of the transmission. 1000 PSI would be neat! That should be enough pressure to blow transmission parts through the side of your garage, not to mention any people nearby.
I don't have a shop manual handy. It does list normal pressure under most operating conditions.
Cargo Master
Joined: Jun 2003
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From: Somewhere Saskatchewan
well you interpret what you want.
As for the harsh 1-2 read this article.
http://www.transmissionspecialty.com...-Volume-06.pdf
http://www.transmissionspecialty.com...-Volume-06.pdf
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