Leaking Oil while towing ONLY

[theOiler]

Guys, I am having issues with my 4 runner leaking oil from the tranny, any help would be great. The scenario below:

I have a 2004 4Runner with 80K miles that I use to tow my steel trailer and race car (total 4.5K). The 4runner is a Sports edition all wheel driver V8 with tow package. I have been towing for few years with no issues however this week I have noticed red ATF oil on the back of the truck and also on the back door. It seems it was leaking soo much oil while I was towing that my race car and the back of the truck got covered by ATF fluid.

I drive the truck on the streets with zero issues and since I change the engine oil myself I never noticed any leaks however, it started to leak only while towing. I went ahead and cleaned the bottom with brake cleaner and drove and it did not notice any new leaks.

I usually tow at 70 miles per hour or so but on the way back this time (after the leak) I towed at 60 miles and did not notice any leak (going to check in the next few hours) The back Is not covered in oil. I am thinking my tranny is overheating gushing the oil out from the breather hole.

Have any of you noticed something similar? I am towing too fast for this truck? Is there a breather hole on this truck?

 

[theOiler]

no one!

 

[TechWrench]

Probably the transmission fluid is getting too hot while towing, and the fluid is blowing out the vent. You don't mention which engine you have. If it is the V8, then you should have a aux trans cooler. If you have the V6, then you don't have an aux trans cooler, unless someone installed it aftermarket. If you have the V8, then I would get the trans fluid changed, and have the aux cooler checked for possible blockage. If you have the V6, and don't have an aux cooler, get one, and still get the trans fluid changed.

There are several good threads on trans cooling and towing here. I recommend going through them for some very good info.

 

[bimmage]

This just happened to me on a 1200 mile trip back to Colorado pulling a 6x12 with a gate (acting like a sail). My truck is the v6 without cooler and 4 speed auto. I'd say I was doing about 75 and saw smoke in the rear (assuming it was from it spraying on the exhaust) and pulled over.

I saw the bottom of the tranny was wet and along the passenger side where a tube and maybe a sensor? was. My AT temp light never came on.

What's the verdict on this? Is it okay to keep driving?

 

[TechWrench]

This just happened to me on a 1200 mile trip back to Colorado pulling a 6x12 with a gate (acting like a sail). My truck is the v6 without cooler and 4 speed auto. I'd say I was doing about 75 and saw smoke in the rear (assuming it was from it spraying on the exhaust) and pulled over.

I saw the bottom of the tranny was wet and along the passenger side where a tube and maybe a sensor? was. My AT temp light never came on.

What's the verdict on this? Is it okay to keep driving?

Unless an external transmission seal has failed, I would suspect fluid blowing out the breather vent. If you have the transmission dipstick, I would check the fluid, and top it off if needed. As long as the fluid level is good, and the transmission seems to be engaging and shifting normal, I would guess that it would be OK to finish the trip. But, I would ease off a bit on your cruising speed until you get back. You didn't mention how much of a load is on the trailer. Once back, I would suggest geting the trans fluid changed. You said that you have 174K on the vehicle. Has the fluid ever been changed before?

 

[bimmage]

Unless an external transmission seal has failed, I would suspect fluid blowing out the breather vent. If you have the transmission dipstick, I would check the fluid, and top it off if needed. As long as the fluid level is good, and the transmission seems to be engaging and shifting normal, I would guess that it would be OK to finish the trip. But, I would ease off a bit on your cruising speed until you get back. You didn't mention how much of a load is on the trailer. Once back, I would suggest geting the trans fluid changed. You said that you have 174K on the vehicle. Has the fluid ever been changed before?

I was towing an empty trailer with a rear gate in 50 mph winds trying to maintain about 70-75 haha. I bought the truck with about 170k and was dealer maintained but Im assuming they never changed the fluid. Has about 197k now. I made it back OK doing about 60-65 and no more signs of leakage. Checking the fluid on the dipstick shows it at full and still has a reddish color to it.

I think here soon ill be adding the cooler, but is it worth it to change the fluid if its still red and not too dirty?

Thanks a lot for your help.

 

[TechWrench]

I was towing an empty trailer with a rear gate in 50 mph winds trying to maintain about 70-75 haha. I bought the truck with about 170k and was dealer maintained but Im assuming they never changed the fluid. Has about 197k now. I made it back OK doing about 60-65 and no more signs of leakage. Checking the fluid on the dipstick shows it at full and still has a reddish color to it.

I think here soon ill be adding the cooler, but is it worth it to change the fluid if its still red and not too dirty?

Thanks a lot for your help.

If, as I suspect, the fluid got too hot and the trans started venting it, I would recommend doing at least a drain and refil. The fluid may not have been totally ruined at this point, but 'refresing' it, IMHO, would be a good idea.

 

[bimmage]

If, as I suspect, the fluid got too hot and the trans started venting it, I would recommend doing at least a drain and refil. The fluid may not have been totally ruined at this point, but 'refresing' it, IMHO, would be a good idea.

Awesome thanks! Im just wondering though, why didn't the A/T Temp light come on first before the fluid got so hot that it came out the vent?

 

[TechWrench]

Awesome thanks! Im just wondering though, why didn't the A/T Temp light come on first before the fluid got so hot that it came out the vent?

Wish I could answer that one. There are some threads in the section that have discussed trans temps while towing, and how the A/T trans temp sensor works. Do a search for them, and they might shed some more info.