41TE Tranny cooler line diameters
 

Anyone know them for sure? All I could find on all par said "about 1/8" or 3/16" tubing.

I need to do a flush and I want to make sure I have the right size tubing to go to the nipple on the transmission. I also want to get a male-male nipple adapter(or a filter of some kind with the right nipple sizes) to attach more(clean) tubing to the cooler line to go into the bucket the tranny will be drawing new fluid from.

I would severely warn against doing a flush, especially if it's high-mileage/never been done.

Drop the pan, change the filter, change the fluid.

That's the plan. Siphon out enough fluid to drop the pan without a mess(I only have a parking lot to work with), drop the pan, clean it, replace filter, then replace the pan gasket, reinstall it, refill to proper level, then flush.

When I say flush, I'm not referring to something like the Jiffy Lube engine flush. I'm talking about replacing ALL of the fluid in the transmission, not just what's in the pan.

Grab your drain pan, take the pan bolts out starting at the rear, when you get to the fronts, just loosen them enough for the pan to drop. Let it drain into the drain pan, then take the last couple bolts out while holding the pan so it doesn't fall and make a mess.

Like I said, I WOULD STRONGLY ADVISE AGAINST REPLACING ALL THE FLUID. I've seen far too many people do this, then end up replacing a transmission 5k later. Just replacing what is lost when dropping the pan is your best bet.

The detergents in the new fluid can eat out everything that's holding your trans together from my experience and friends/family, IT WILL.

The only thing close to a realistic argument against transmission flushing(with trans fluid) is the PH level making parts brittle where the current fluid is very old. This is only true if you leave in fluid too long and even then there is no real solid evidence of this..

The only reason I don't do it is financial($5.00/qt). I just use break cleaner on the pan and magnet, and put the gasket and filter kit in and use certified ATF+4 like Autozone ATF+4.

EDIT:There are <$200.00 aftermarket oil and trans coolers that are very worth the investment especially if you haul and especially if you city drive. If you have the stock dedicated-radiator ones(I don't know which option indicates they are installed) those are good for city.

I'm doing the filter, a fluid flush, and the solenoid pack all in one go. It's not out of my pocket, my grandpa is funding it. "If this isn't enough to fix it, you're SOL, kid."

The fluid isn't that bad looking, really. It's not the bright red it should be, but it's not black either.

As for radiators, my van happens to have the "towing package" from the factory, although in this case it's sans trailer hitch. The wiring is there, the tranny has the dedicated cooler that completely bypasses the engine's radiator, and there WERE heavy duty flashers installed but I have since replaced those with different ones that don't refuse to cycle with all the LED bulbs I've installed. But I digress.

I have everything I think I need. 10 quarts of fluid(all I had the money for alongside everything else) two 5 gallon buckets, a little inline filter for the new fluid going in, and two 2ft lengths of 3/8" ID "radiator overflow" tubing. Also some plastic-wing-nut-equipped hose clamps.

I just hope 3/8" will work, mainly in terms of hooking onto the "to cooler" nipple on the transmission itself.

Any used vehicle I have bought, that I've had the trans flushed have had issues in the next 5-10k, along with many people who insisted our shop flush theirs.
It's experience talking, not wild theories. I've had many vehicles make 300k+ with just doing fluid/filter/cleaning pan.
I prefer not to gamble with my transmissions.

I haven't done it enough to know because the economics I pointed out. In theory it'd extend the life. The PH claim and air pockets are the only two things I can think of that could actually have a negative effect.

There's also the detergents in new fluid that are generally gone in old fluid. Between the detergents and the change in PH, new fluid can wreak havoc on a high mileage trans.

I'm having a hard time buying that, as if such is truly the case, then those same detergents and pH would be causing issues if one simply replaces what was lost by dropping the pan with new fluid. It's still introducing new fluid to the system.

When you say you've had issues has it been that you're taking the vehicle into a shop for the flush, or are you doing the flush yourself? Because I've seen plenty of horror stories about places like Jiffy Lube and Les Schwab doing all sorts of bad things with "flushes". Engine "flushes" that completely murder the engine within a week, oil changes that never happen, additives that shouldn't be put in, the list goes on.

Even if it is the case that this will hurt the transmission, this van is probably getting replaced soon anyway. The biggest reason I'm doing this is because my retired-air-force-colonel grandfather sent me $300 for supplies and (quite sternly) said, "Get it fixed. If this isn't enough, drive it till it dies completely." So I have the supplies for a DIY fluid replacement including filter and pan gasket, and a new solenoid pack as well.

Lastly, to be blunt, I was only asking for the inner diameter of the tubing in the OP. Not whether or not it would work. Wasn't trying to start a debate.