When in doubt, change it. Full service/flush should be 150..better than 3 - 4 M for a trans.

 

You could just check the dipstick and see how it looks. Do a couple drain and fillss

 

+1 on the drain and fill. You probably don't need to do a flush. What is the color of the current tranny fluid?

 

The color is dark maroon. I would say it doesn't smell burnt, but it definitely should be changed, I would say. I texted the previous owner who was kind enough to reply that the tranny had a flush at 62k miles. So a decent thing to do would be about 3 drain-n-fills, spaced a few hundred miles apart?
About towing... I plan to tow a pop-up camper (probably no more than 2000 lbs.) this summer. Am I correct that the '07s came standard with the towing package? Would that include a transmission cooler and an oil cooler? What was included in the package? Should I add anything besides the hitch and T-adapter?

 

The color is dark maroon. I would say it doesn't smell burnt, but it definitely should be changed, I would say. I texted the previous owner who was kind enough to reply that the tranny had a flush at 62k miles. So a decent thing to do would be about 3 drain-n-fills, spaced a few hundred miles apart?

That would work.

 

Would any Sienna experts advise a trans cooler or an oil cooler for towing, or does this van (2007) already have adequate cooling built-in?

 

Would any Sienna experts advise a trans cooler or an oil cooler for towing, or does this van (2007) already have adequate cooling built-in?

Someone posted that the 2007 does come with the cooler built in.

http://www.siennachat.com/forum/69-towing-hauling/6880-adding-oil-cooler-07-09-sienna-towing-2.html

Why not call your local dealership and ask the service manager to confirm. In my 98 it has the cooler which is behind the bumper. Last time I removed the bumper I made sure i gave the cooler one huge degreasing and rinsing with water.

 

Thanks for the info and advice.

I've been reading quite a bit on forums concerning towing, especially "Sienna Gen-II Towing" thread. I now understand (I think) that the engine oil cooler is a little round device built onto the front of the 3.5 that cools the oil using the (not as hot?) coolant. And I understand (I think) that the transmission oil cooler built into the radiator is a little beefier - as is the radiator itself - in the 2007's, as are the fans (maybe), etc. I picture in my mind a setup that takes coolant heat, crankcase oil heat, and transmission heat, blends all that heat together into the radiator, then relies on the radiator to keep it all cooled down together as one big unit.... (maybe).

I guess at this point I feel OK about flushing and filling the coolant and changing out the transmission fluid with new WS and calling it good. The camper can't weigh more than 1500 lbs or so.

 

My wife had the 07 Sienna into the dealership today for a multi-point inspection. The service tech calls me and says the back brakes need done bad, I say OK do it.
Then when I asked about the condition of the ATF, he says it's WS, and being a synthetic it never needs replaced. :0
I didn't bother saying anything else. I have decided that before I tow, I will do a soft flush of my transmission, as seen here.

 

My wife had the 07 Sienna into the dealership today for a multi-point inspection. The service tech calls me and says the back brakes need done bad, I say OK do it.
Then when I asked about the condition of the ATF, he says it's WS, and being a synthetic it never needs replaced. :0
I didn't bother saying anything else. I have decided that before I tow, I will do a soft flush of my transmission, as seen here.

I would never say that any fluid is lifetime and never needs replacing.

 

Sorry it's been a couple months since I was on here.
I have completed a soft flush of the tranny fluid, and the procedure was VERY easy and it went very smoothly and quick. I don't know why I was worried - expensive item to mess up, I guess.

 

We have an 08 awd. I pulled the cooler line nd flushed 12qts when we got the van at72k. based on my research, it seems the ws is good to 60k or so, maybe longer in the fwd.uthe trans factory cooler is more of trns preheater. the trns hets hot nd is slow to cool down. using a scanguage2, the trns temphas been monitored. w ave seen 260f briefly while climbing mountais. typicl trns tmp is 200-220 on hot dys.i would not towwith this van without trans temp guage. check out the thread on the easy trns cooler $60 and 1hr install.