Automatic Transmission Fluid Change

Snap-On Promotional Video

A question about changing automatic transmission fluid, but first, some background...

I frequently get my oil changed at Jiffy Lube. I had my daughter's Mustang (formerly mine) in for an oil change at a Jiffy Lube in Annapolis, Maryland awhile back and they did their usual upsell and recommended that I get an automatic transmission fluid change. Since the car definitely need the fluid changed I agreed (it was about eighty bucks as I recall).

The thing that I was impressed by was that they were using a machine which apparently timed the cycling of the torque converter, and with the car running, they put a single clear plastic tube down the ATF dipstick tube and the machine pulled out the old burnt fluid and pumped in fresh fluid in an alternating fashion in time with the torque converter. They claimed that this system got all (or virtually all) of the old fluid out and replaced it with clean fresh fluid. I watched the clear tube as the machine did it's work for about twenty minutes or so...pull out the old fluid, pump in the fresh fluid, through the same clear tube. The machine cycled back and forth, back and forth, until it was done. And not only did it replace all the old fluid at once, no one ever touched the actual transmission. The machine really did what it was supposed to do and the transmission shifted noticeably better thereafter. The whole service only took about half an hour.

So of course I was interested in the same for the NSX. I inquired very specifically about this service at another Jiffy Lube near where I work and they told me they could do it. But when I actually brought the car in to have it done, they seemed confused and said they couldn't do it, apparently because they had a different machine than the other place.

I have had the usual (partial) transmission fluid replacement, but I would really like to get one of these complete transmission fluid changes. I need to call the Jiffy Lube in Annapolis I guess, but in the meantime, does anyone know of any other place that the same type of transmission fluid change can be done?

A word of caution: A transmission flush is different from a transmission fluid change. This discussion is regarding a transmission fluid change.

Yeah I have the same question!

Assuming the NSX has trans cooler lines running to the radiator like most automatics, find a place that has a machine that looks like a giant syringe built into a cart. I think they're called trans tech or total tech. They use a coupling to tap into the line running to the radiator & run the car. As the fluid goes thru the line into the machine it pushes out an equal amount of new fluid. No fuss, no muss & it gets everything.

Are they using Honda Z1 fluid?

Dave

Assuming the NSX has trans cooler lines running to the radiator like most automatics, find a place that has a machine that looks like a giant syringe built into a cart. I think they're called trans tech or total tech. They use a coupling to tap into the line running to the radiator & run the car. As the fluid goes thru the line into the machine it pushes out an equal amount of new fluid. No fuss, no muss & it gets everything.

Click to expand...

I did some research based on your response and learned that several manufacturers, including T-Tech, Snap-On, Sun, Robinair, and RTI make transmission fluid exchangers that connect to the trans cooler lines on the typical car.

Referring to the 1991 NSX service manual (downloadable from the Wiki), on page 392 I find this quote: "ATF Cooler - With this mid-engine type car, the radiator is mounted at the front of the car, so the ATF cooler is installed directly on the transmission housing." Page 393 shows a basic diagram of the transmission, depicting the location of the transmission cooler. Page 433 shows a basic diagram of the ATF cooler, identifying inlet and outlet hoses, which appear to be just that, hoses, as opposed to metallic cooling lines with fittings. Page 476 describes how to check/change the transmission fluid using the conventional method. Fluid volume is listed as "3.1 US quarts at change, 7.4 US quarts after overhaul, 6.7 US quarts after overhaul with new torque converter." using "Honda Premium Formula Automatic Transmission Fluid or an equivalent DEXRON-II type automatic transmission fluid." Of note is that there is no mention of a filter or screen, and the fact that changing the ATF using the conventional method replaces less than half the total volume of old ATF.

Side note: While poring over the NSX service manual I was amazed by the incredible complexity of the automatic transmission.

While it might be technically possible to somehow cut and tap a T-fitting into the hose of the trans cooler, so far I am inclined to believe that this type of machine is impractical for servicing the NSX automatic transmission, because the ATF cooler lines on the NSX are hoses (similar to radiator hoses) with hose clamps at the ends instead of metallic lines with fittings. The fluid exchanger machines that utilize the transmission lines all come with an assortment of adapter hoses with fittings on the ends.

This leads me back to the other type of machine that utilizes a clear tube inserted into the dipstick tube. After some research, I discovered that several manufacturers make this type of fluid exchanger. (One example is the Snap-On TransKare 1.) I will have to look around and find out who uses one of this type in my area.

Thanks for your input.

Why not find a shop w/ a t-tech & see if it is possible & advisable to use it on an NSX? Or contact the manufacturer & see what they say. Can't hurt to find out.

Why not find a shop w/ a t-tech & see if it is possible & advisable to use it on an NSX? Or contact the manufacturer & see what they say. Can't hurt to find out

Click to expand...

.

A great suggestion, but I actually did that already. The second Jiffy Lube I checked had the type of machine that used the trans cooler lines. To elaborate, I asked very specifically about the NSX and the tech told me that they had done several NSXes with automatic transmission (already a dubious claim). But when I took it in they were stumped, leading me to believe that the guy was just kind of pulling an answer out of his a**.

Here is an RTI machine that has both modes, cooler line mode and dipstick tube mode.

Guys,
I have never worked on an NSX with an auto tranny. I have worked on a lot of Hondas with auto trannys. What I do is find the line that returns the fluid back to the tranny. I disconnect that line and attach a clear plastic line to it, and then put the other end in a catch container (clear milk jug, you will need three). I then drain the trans fluid from the tranny, refill the fluid and leave the funnel in the fill tube. I then open 12 qts of fluid, start the engine. Watch the amount of fluid that is collected in the container and pour new fluid into the fill tube at the same rate. Watch the color of the fluid in the clear line and stop when the fluid looks like the new fluid.

The normal flow of fluid in a tranny is from the pan to the pump to the converter, where all of the heat is produced, to the cooler and then back into the valve body and then back into the pan.
This method works great on Honda Accords etc since there is no changeable filter, only an internal screen.

So now all you have to spend is whatever a case and half of fluid cost, some clear plastic line and some time. This process works best with three people, one at the ignition, one at the catch containers and one pouring in the fluid.
Brad

I had my transmission fluid changed yesterday the conventional way, except after the first refill they ran the car a little bit and then drained and refilled it again. So by draining and refilling twice I estimate that they changed about 70% of the old fluid.

Still on the lookout for a machine that will accomodate the NSX via the dipstick tube. If I find one of those I will get it changed again.

Jett said:

I had my transmission fluid changed yesterday the conventional way, except after the first refill they ran the car a little bit and then drained and refilled it again. So by draining and refilling twice I estimate that they changed about 70% of the old fluid.

Still on the lookout for a machine that will accomodate the NSX via the dipstick tube. If I find one of those I will get it changed again.

Click to expand...

I just recently had my transmission fluid drained and refilled, and will repeat within 10,000 miles. Has worked out well with my prior Honda.

This is how to do it properly and get about 97% of the fluid out without hurting the transmission:

Park car on level surface.
Drain transmisson oil.
Add new transmission oil back it, the same amount that came out.
Cover everything up, drive for 5 minutes and shift though all the gears.
Park car on level surface
Drain transmission fluid again
Add new Transmission oil back in
Cover everything up, drive for around 5 mintues and shift though all the gears.
Park car on level surface
Drain Transmission oil
Add new transmission oil back, the same amount that came out
Go for drive and enjoy new transmission fluid.

This is called the 3x drain and refill method. This has been used on many honda and acura transmissions and works well. I personally would not use the machine as one small error in it can ruin a transmission.

I like your 3x drain and refill method. :smile: That sounds very safe and thorough.

One of the things I liked about the "Dipstick Tube Method" was that it used a clear hose. You could watch the fluid being pulled out and replaced. Having observed it once, and seeing how smoothly it operated, I would be comfortable with it again if I can find a place that does it.

Hey Guys I manage a Valvoline Instant Oil Change. The Machine that was first used on the mustang is a TFE machine the old machines t-t techs
have to be hooked into the cooler lines. TFE machines work through
Dipstick tubes. The NSX trans stick is very short as are all Hondas
but the machine that they used on the mustang will work on the nsx all
you do is insert the TFE tube down in the trans the same distance
as the dipstick and the machine will do all the work. These things work great. BUT make sure where ever you have it done they use a fluid
that covers Hondas fluid . At my shop we only use MAXATF which
exceeds all of the Honda Fluids Specs. Almost all Valvoline Instant oil changes have the new machines. Give them a try.

I've rebuilt a fair share of auto transmissions.

OLDMAN has it correct: the process he outlines does the same "100%" fluid change as the fancy machine.

The hose and clamps implementation work just fine. I can do it alone, just let it take in enough fluid until it runs clean. Shut everything down, reconnect and then top off the fluid. It is messy though.

You can make a nice permanent install fluid change apparatus with three valves and two T fittings and make it quite efficient. Cost you $20. No machine to buy, maintain and take up space.

apparently timed the cycling of the torque converter

Click to expand...

Is the machine hooked into the transmission harness? I'm not sure of the ODBII can invoke a torque converter lock-up...anybody?

engine running and warm. (operating temp)

Thank you Adnan. :smile: