Transmission overheating!

[chuckwagon101]

1999 ford explorer sport....6 cyl....4 wheel drive

I just had a new transmission put in this vehicle.....

The trouble light still comes on......

Just back from a 120 mile trip. The light came on at 53 miles.....I would stop and turn off the vehicle. The light would not be on when I started driving again but would turn on every 10 or 12 miles thereafter!

When I got home, I felt of two lines going to a small radiator behind the regular radiator.......it is at the bottom on the right side.

The lines were cool to the touch! The transmission case was smoking hot!

I pulled the transmission dip stick and it was super heated!

Why is this happening?

I had the same problem with the previous transmission overheating and it went out about 5 months after it started overheating. I did not know at the time that it was overheating.

Any help or suggestions appreciated.

Thanks, Chuck

 

[koda2000]

the trans pump should be moving fluid through those lines and small rad/cooler and the radiator. it appears you have a clog somewhere. i wouldn't drive it until you get it figured out and once you do, you might want to change the fluid as it's probably burnt.

maybe you can get whoever changed the trans to fix it?

 

[Maniak]

1999 ford explorer sport....6 cyl....4 wheel drive

I just had a new transmission put in this vehicle.....

The trouble light still comes on......

Just back from a 120 mile trip. The light came on at 53 miles.....I would stop and turn off the vehicle. The light would not be on when I started driving again but would turn on every 10 or 12 miles thereafter!

When I got home, I felt of two lines going to a small radiator behind the regular radiator.......it is at the bottom on the right side.

The lines were cool to the touch! The transmission case was smoking hot!

I pulled the transmission dip stick and it was super heated!

Why is this happening?

I had the same problem with the previous transmission overheating and it went out about 5 months after it started overheating. I did not know at the time that it was overheating.

Any help or suggestions appreciated.

Thanks, Chuck

IIRC, that year (and newer) trans (5r55e) doesn't let the fluid out of the transmission until it gets to a certain temp. Until it gets warm it bypasses the cooler (transmission heat exchanger).

Since the vehicles moves, you know the pump is running. I'd think the lines are plugged or the bypass valve in the transmission isn't working. Since neither line got warm (it should get warm, if it is isn't "flowing" through the radiator due to a plugged heat exchanger in the radiator) I'm leaning towards a bad bypass valve.

There is a 5455e rebuild diary on here (I can't search for it right now) which "should" have information about the bypass valve.

~Mark

 

[2000StreetRod]

ATF flush?

. . . I just had a new transmission put in this vehicle.....
The trouble light still comes on......
Just back from a 120 mile trip. The light came on at 53 miles.....I would stop and turn off the vehicle. The light would not be on when I started driving again but would turn on every 10 or 12 miles thereafter!
When I got home, I felt of two lines going to a small radiator behind the regular radiator.......it is at the bottom on the right side.
The lines were cool to the touch! The transmission case was smoking hot!
I pulled the transmission dip stick and it was super heated! . . .

There is a thermostatic controlled valve in the 5R55E that opens the external cooling loop when the ATF in the torque converter reaches 150 deg F. A flush of the cooling loop should be performed whenever a transmission fails to remove metal particles. The ATF flows thru the radiator internal ATF cooler and the auxiliary cooler if available. As I recall the auxiliary cooler is mounted in front of the A/C condenser on passenger side instead of behind the radiator on the right side where the radiator fan would hit it.

It takes my Sport about 20 minutes of driving before the ATF temperature reaches 150 deg F and the external loop opens. When the new transmission was installed was the external loop flushed?

 

[chuckwagon101]

There is a thermostatic controlled valve in the 5R55E that opens the external cooling loop when the ATF in the torque converter reaches 150 deg F. A flush of the cooling loop should be performed whenever a transmission fails to remove metal particles. The ATF flows thru the radiator internal ATF cooler and the auxiliary cooler if available. As I recall the auxiliary cooler is mounted in front of the A/C condenser on passenger side instead of behind the radiator on the right side where the radiator fan would hit it.

It takes my Sport about 20 minutes of driving before the ATF temperature reaches 150 deg F and the external loop opens. When the new transmission was installed was the external loop flushed?

I have no idea about the external loop being flushed. Is it something I could do?

All I know is it said.....rebuilt transmission...1200 dollars.......installation and prep ran the bill to almost 1800 dollars.

 

[fatfenders]

1999 ford explorer sport...

Any help or suggestions appreciated.

Thanks, Chuck

I don't really know if you configuration is the same as mine below ('04 4WD 4.0 Sport Trac) but I always like first to isolate problems with efforts that are (1) easy) (2) free.
You might try and isolate the problem by pulling the service line to the (engine) radiator trans cooler. Grab a length of hose (preferably clear tubing) big enough to slip over the flare end, pull the service line and slip the tubing on, point the other end of the hose into a container (I hate even the smallest ATF spill), and see if any fluid comes out. Despite the advertized thermostatic controlled valve fluid will pour out of this line on my machine at cold startup.
Obviously, if you see a stream of fluid the problem is after that point, otherwise, before.

 

[Maniak]

I have no idea about the external loop being flushed. Is it something I could do?

All I know is it said.....rebuilt transmission...1200 dollars.......installation and prep ran the bill to almost 1800 dollars.

Since you paid close to $2k for a transmission rebuild it should be under warranty. I wouldn't do anything to it other than let them know its coming back and that they need to fix it..

If you mess with it they may say you caused it or charge you some extra because they have to undo what you did (if anything).

~Mark

 

[2000StreetRod]

no warranty?

I suspect the transmission was replaced before the vehicle was purchased by chuckwagon101 and he only has the receipt and no warranty. It's been my experience that only the better transmission shops provide a transferrable warranty. fatfenders, I agree that what's published and what actually happens in this case are different. When I separated my external cooling loop at the auxiliary cooler I observed ATF from both sides even though the transmission was cold. I did note that one side had a greater flow than the other. Both sides (outlet and inlet) are under pressure (there is no suction pump). The flow results from a pressure differential.

However, before I repaired my blown out valve body gaskets I noticed that my upshift flare increased significantly when the ATF temperature reached 150 deg F. I assumed that was because the external loop opened.

 

[fatfenders]

I observed ATF from both sides

THAT is very interesting... never even thought about that possibility. When I did my little test however, I didn't notice fluid exiting the cooler. Of course, I only did it long enough to observe the fluid start to exit the line... maybe it takes a little longer. I did note that what I determined to be the 'service' line is the lower of the two on the transmission. Which one did you observe to produce the most fluid?

 

[2000StreetRod]

which port?

I found a 5R55E external cooling flow test in my 2000 Workshop Manual. It states "Remove the cooler return line (rear fitting) from the fitting on the transmission case." Also "Disconnect the hose from the cooler return line and connect it to the converter outline fitting (front fitting) on the transmission case." I was thinking the two fittings were vertically aligned. Assuming that they are staggered then upon inspection I should be able to answer my question. I found a drawing of the heat shield in the Workshop manual that shows the external cooler ports. The lower one is perpendicular to the case and the upper one is at a 45 degree angle to the case pointing forward. Therefore the lower one (rear fitting) is the return port and the upper one (front fitting) is the supply port. This agrees with my test results.

 

[chuckwagon101]

I suspect the transmission was replaced before the vehicle was purchased by chuckwagon101 and he only has the receipt and no warranty.

That's a wrong suspicion.

The vehicle has been in my family from the git go. The original transmission went out a couple of months ago.

The warranty on the replaced transmission is 90 days or 4,000 miles....whichever comes first.

I am good as to warranty.

I thought if it was something real simple that I could fix....I would do it.

If not, then I will take it back to the garage that did the transmission work.

I just hate to be without a vehicle for 3 or 4 days.

From the sound of things......it looks like I am on shoe leather for a awhile!

 

[Markaprice73]

Sorry for you troubles. Good luck.
I'm curious about your warranty. You said in different posts that you had a "new trans"/"a re-built trans"/"replaced trans". Which is it exactly? If they re-built your original trans. It should be at least a 12month/12K mile warranty. New trans longer. Put in a used one- I could see the 90/4K. But $1800, I'm assuming they re-built your original.
It stinks to not have your ride for awhile. But, don't be content with it until you are having 0 issues. Then and only then, ask if they can give you a 12mo/12K. Which it really should be.

 

[chuckwagon101]

Sorry for you troubles. Good luck.
I'm curious about your warranty. You said in different posts that you had a "new trans"/"a re-built trans"/"replaced trans". Which is it exactly? If they re-built your original trans. It should be at least a 12month/12K mile warranty. New trans longer. Put in a used one- I could see the 90/4K. But $1800, I'm assuming they re-built your original.
It stinks to not have your ride for awhile. But, don't be content with it until you are having 0 issues. Then and only then, ask if they can give you a 12mo/12K. Which it really should be.

I don't think they operate that way. All the work I have had done at this garage before has been the same 90 day/4,000 mile type.

I am taking it back Monday and see what they will do. I HAVE to have it repaired .....no matter what they say. Regardless of what you hear.....you are at the mercy of most ANY car repair places. They seem to hold all the cards, so to speak.

Thanks for the advice and suggestions. I don't feel capable of finding the cause to the overheating and repairing it. So I will go back to the garage and see what they will say. It is still in "warranty" as I don't have but just under 1,000 miles and it has only been about 6 weeks or so.