Transmission Fluid Cooler in Radiator Burst

[Brunoski]

Well here goes, coming home this night my tranny would not shift up to go over 30mph, it would just rev up to 3500rpm. At first I thought that it was too slushy or something and the wheels were turning, but it made no difference in 2wd or 4wd. Finnaly getting closer to home it would not shift up over 25.

Would this be part of the Over Drive issue common to these auto tranny's? This however usually appeared going onto the highway, while I was on the street.

The fluids were replaced last summer with a cooler install.

Alas, at times I would notice a burned rubber smell coming from underneath sometimes. Nothing to strong, something like grease thrown from an overfilled U-joint.

And another thing, popped the hood to check for shavings in the fluid, did not see any but it was dark out, so in the morning I'll check again. However, I noticed that the overflow bottle for the coolant had overfilled and there was some fluid around. I didn't see the temp gauge go over half. Could this be related or a stuck thermostat.

I am imagining water pump issues along with the timing belt and a tranny rebuild. What a clusterfudge.

[Brunoski]

Update: This morning checked under the hood. I believe the Radiator :loser: is the culprit as it appears that the fluid in the overflow tank is mixed tranny fluid with coolant. Also the tranny looked dry on the dipstick. Have to get a case of tranny fluid so that I can make it to the mechanic's :wrenchin: tomorrow. I hope the tranny is not fudged up :headscratch:....

[4runnerchevy]

Jump out your tranny cooler, by removing the hoses from the cooler, then tie them together. Pull your tranny pan and let it drain. Then put the pan on, and fill it up. This should get you to the mechanic, without much more damage. You could even fill it up run it through gears, then drain it again.

Or get a tow truck.

.02

[Brunoski]

"Jump out your tranny cooler, by removing the hoses from the cooler, then tie them together."

Do you mean to by pass the radiator and go to straight to the aux cooler or totally disconnect any cooling?? If so will that not drain the rad from the leak?? Kinda confused... Bottom line I see that it is not safe to drive even with fresh fluid put in to prevent slippping for the trip...

[4runnerchevy]

It sounds like you need a tow truck !

[Brunoski]

Question for those who replaced their rad, should I buy straight from the dealer? Its $400 from the US plus shipping, and probably around $600 locally.
Or about $300 from www.bestpricecarparts.com which they claim is OEM. Even if it is not oem, is it wrong to go aftermarket?

[Brunoski]

It was not the lines that went, it is a crack in the wall of the rad separating the area between the engine coolant and the trans fluid. I suspect that only one crack appeared near the sending line as the tranny dipstick was dry so none of the mixed fluid went back in, it was only sucked out.

I have a feeling that the recent cold snap caused some metal fatigue due to the drastic temperature changes and salt on the road. At the same time, the same cold helped to prevent overheating as the temp gauge was normal.

I already installed an aux tranny cooler last summer. At 93k miles it can happen to anyone. My buddy's old man is a diesel mechanic and says that it is common on school buses. So its probably a design flaw of the rad.

So far this is what my reasoning comes to and I just want to get a rad before I go to the mechanic so that the truck is not just sitting there. Hopefully I dont get anymore bad news when I get there.

[Scuba]

Its actually a common problem with the auto transmissions on that gen, The tranny lines bursting inside the radiator...:bling:

[skjos]

Yup, it's the strawberry milkshake.
Typically the tranny line bursts inside the radiator, and the pressurized coolant pushes its way into the transmission fluid resulting in strawberry milkshake colored transmission fluid.
It's weird that in your case the transmission fluid went into the radiator vs the other way around.

[Brunoski]

Well, so far today we got the engine fully flushed. So far we used a pale, 20L, of regular ATF to flush the tranny, and expect to use another one.

As far as the order of the contamination, I think that when I first spotted the issue, the tranny fluid was just leaking into the antifreeze. Then when the engine was off and cooled off, the pressure just pulled it back into the transmission.

So far no issues popped up and it is believed that the tranny can be saved, unless it dies from the O/D issue occurring on the 340F models.

Anyone know how to edit the title, as I now know what the issue is?

[MTL_4runner]

Anyone know how to edit the title, as I now know what the issue is?


Hopefully that is a better title for you.


Once you get the engine and tranny flushed all should be fine. Sounds like you caught it in time to be saved. Obviously get a new radiator, plug the cooler holes (you don't want stuff corroding the radiator from the inside) and run an external cooler of appropriate size (20,000 GVW or more!)

[Brunoski]

Finished flushing today, took 2 pales (40L) of regular ATF to get it back to regular color. Just going to drive around for a couple of days then just drain and fill with synthetic. It would be real hard to do all this flushing without the hoist lift. Just drove it in the air (maybe not the safest :tapedshut:).

If I understand you Jamie, are you saying to totally by pass the rad and go straight to the aux cooler? I asked the mechanic already, he said that it may take too long for the tranny to warm up in the winters, as you know Canadian winters are harsh. The factory way, the antifreeze warms it up a little as both fluids are being circulated.

Thanks for the title change.

[MTL_4runner]

Finished flushing today, took 2 pales (40L) of regular ATF to get it back to regular color. Just going to drive around for a couple of days then just drain and fill with synthetic. It would be real hard to do all this flushing without the hoist lift. Just drove it in the air (maybe not the safest :tapedshut:).

If I understand you Jamie, are you saying to totally by pass the rad and go straight to the aux cooler? I asked the mechanic already, he said that it may take too long for the tranny to warm up in the winters, as you know Canadian winters are harsh. The factory way, the antifreeze warms it up a little as both fluids are being circulated.

Thanks for the title change.


The tranny fluid is under constant shear and the bands are slipping to make the vehicle go forward and all that internal friction is really what's heating up the fluid. I've started my truck in -40F / -40C and hopped in and started driving and never had any issue and I doubt the tranny fluid could be under much harsher conditions. I really think it would tend to be a moot point if you ran it through rad cooler first or just ran it straight to the aux cooler. I've also heard of some people switching the routing depending on if it is winter or summer but that's too much hassle IMHO.

[Brunoski]

Jamie are you running the trans cooling straighs into your aux? As far as I remember I installed the Hayden 679 which is I think for 30K gvw. It does make sense what you are saying, perhaps when I go do my drain and fill I'll tell the mechanic to swap the lines to go straight and block of the rad outlets. Since the rad really only contains the cooling line in the very bottom brace. Just have to go to Napa to get some plugs...

[MTL_4runner]

Jamie are you running the trans cooling straighs into your aux? As far as I remember I installed the Hayden 679 which is I think for 30K gvw. It does make sense what you are saying, perhaps when I go do my drain and fill I'll tell the mechanic to swap the lines to go straight and block of the rad outlets. Since the rad really only contains the cooling line in the very bottom brace. Just have to go to Napa to get some plugs...


The 679 should be plenty big enough for summer without overcooling during winter. I'm only running the 678 but I just haven't gotten around to blocking off the rad cooler to just run the aux. I was rushing to get my swapped motor in before winter so I didn't have time before it got too cold to bother. I've seen quite a few of these rad coolers blow now so I wouldn't risk it myself since the alternative could be a blown motor (not going through that again!) or tranny. I wouldn't hesitate for a second to do it.