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2001 Toyota Sequoia - Transmission Fluid/ Coolant Fluid

Hello all. New to the site!

I really am stranded in State College PA (Sunday afternoon, mothers day)

Yesterday my transmission slipped as I accelerated from a stop off the highway exit ramp. It grabbed almost immediately and no problems till I got to my destination about 2 miles down the road…fluid was dripping from the underneath the engine…reddish/pink fluid. Engine was not over heated (according to the gauge). Pulled car off driveway and down the road a bit and transmission was really slipping when trying to accelerate quickly (no issue with slow acceleration). Checked transmission fluid and it was not covering the stick. I thought maybe I burst a transmission coolant line but upon inspection no fluid on that. So I added 1 quart of transmission fluid this morning and started the car to hope to find the leak. No immediate leaking the transmission case, seals or lines. But I did notice that when I started the car the coolant reservoir was “bubbling”. After about 5 minutes to allow the engine to warm and the coolant gauge to come to normal operating range I noticed coolant reservoir/overfill spewing out a pinkish foamy fluid and then checking the transmission fluid level it was drained again (no fluid on stick when running). One last fact…the fluid temp coming from the overflow was cold, so was the radiator fluid after I popped off the radiator cap…but the dashboard temperature coolant gauge was at the mid point/normal operating temperature of the scale.

So my question is…where do I take the car to have it looked at…a transmission shop, or a typical full service mechanic? Any ideas as to what is wrong here? Is the transmission fluid co-mingling with the coolant fluid and if so how does that happen!!!

Thanks in advance…Stranded out of now!

You’ll need a transmission shop for this reason - it seems apparent that you did blow a cooler line, but one of the passages inside of the radiator. The cooler lines run into the radiator, so your radiator cools your coolant and your transmission fluid. If the only thing that happened is that trans fluid entered the coolant then the transmission might be ok. (All of that slipping you let it do was very bad.)

If, on the other hand, you also ended up with coolant in the transmission fluid then chances are it is game over for the transmission.

So I’d say you need a transmission shop because an expert on transmissions has to be able to evaluate and advise. A general repair shop will probably sell you a new radiator, change your trans fluid, send you on your way and then stare blankly and shrug next week when your transmission is dead.

Do not use a nationally known “chain” type of transmission shop. You need a locally owned independent with a good reputation.


Thanks for the quick response and advice.

Like cigroller said, sounds like your radiator failed internally allowing transmission fluid and coolant to mix. If this is in fact the case, you need:

A. Best case scenario–new radiator, complete cooling system flush with detergent (probably twice), a transmission fluid flush followed by a pan service with a new filter and fluid.

B. Worst case scenario–New radiator, complete cooling system flush as above, and a complete transmission removal and overhaul. Antifreeze/coolant is “toxic” to the clutch material inside your transmission.

You could just try A and hope for the best.

I have the same vehicle, so I’m familiar with the Sequoia but haven’t had this problem. I do think you will end up with a new radiator due to failure of your current one. To save space it is pretty common to integrate the cooling of the transmission fluid and coolant into one radiator. The downside is the potential for mixing of the fluids if the radiator fails in a certain way.

If it were me, I wouldn’t start up this Sequoia. Have it towed to either a Toyota dealer, a good independent mechanical shop, and my last resort would be an independent transmission shop. Running the motor and moving the car will just make matters worse. You have fluids getting into the wrong places and all that can lead to is more problems for either the motor, transmission, or both.

I believe a good shop can replace the radiator and take off and put back on the necessary parts in that process. This really isn’t the specialty of a transmission shop. I use only genuine Toyota fluids in my Sequoia and I’d recommend that to you once all is ready to refill the fliuds. Generic fluids can cause problems, both coolant and transmission fluids I’d recommend sticking to a genuine Toyota fluid. When it is all said and done the dealer will charge more, but in this case I’d go that route unless your really have a great shop you know and trust. I have such a shop but if you don’t a Toyota dealer could be your best option.

I think the safest bet in a situation like this is the Toyota dealer, even if it turns out not to be the cheapest. As others have said, you probably need both cooling system and transmission work here. If you’re lucky, a dealer might also have a loaner available.

At least you picked a walkable and fun town in which to be stranded!