help please

[shenKing]

I am looking at the tranny cooler lines schematics for the 92 sts as well as the lines in the car and am confused. Here is what I think: the oil sending line from the tranny goes to the upper end of aux cooler, and from the lower end of the aux cooler it goes to the upper side of the radiator and comes out from the lower side of the radiator back into the tranny.

However, this would conflict with the labels on the schematics, which labels the upper aux cooler as outlet and lower aux cooler as inlet.

Question is : what direction is the tranny fluid flowing at the upper radiator connection, is it going into the radiator or flowing out of the radiator?

BTW I am trying to flush (through one of the cooler line, and hence the above question) and fill the tranny fluid at the same time with the engine on. Any advise would be much appreciated.

Thanks.

[adallak]

Yeah... the description is so confusing! I would take off the upper line of the main cooler (which is in the radiator). It's most likely there the oil will come out then you start the engine. I remember a post about changing ATF this exotic way, but cannot recall the name of the guy. I can post the picture from the service manual, but it is really confusing: if they call the upper line "sending" why do they call the lower auxiliary cooler line "inlet"? Go figure!

[Ranger]

I am not sure but I would guess gravity would come into play. In at the top and out at the bottom. Why pump it up hill? Radiator is the same way, in at the top and out at the bottom.

[shenKing]

Thanks for your inputs.

It was what I thought and it is nice to get confirmation from you guys. Didn't want to hook up the drain tube on the cooler line to find the oil coming out the other end!

I don't know if you followed my post earlier regarding my VCC engagement problem. This problem cropped up after I dropped the pan and change the ATF to mobil synthetic. Prior to this the cooler line blew and lost most of the synthetic ATF fluid. The dealer fixed the line and added regular ATF. Anyhow, I diagnosed the E039 problem according to the manual diagnostic chart and all appears to pass except the last bit whch points to tearing down the tranny. My thought is if the electrical and PCM all appears to be ok and all I did was to switch to synthetic, why not try changing back to regular ATF before spending a ton on the tranny job. I am hoping it's worth the try.

[jschunke]

In my 94 Seville ATF flows in at the

bottom of the main radiator, out at

the top. Don't bother filling the tranny

while draining the top line. The new fluid

will go right back out without circulating

through the tranny. Also, contrary

to what I raed, the bottom line won't

suck in fluid. What I did was open

the top line and run the motor till it

stopped flowing which is equivalent to

draining he pan with much less work. But

it can't hurt to drop the pan to clean

the sludge.

[shenKing]

does your 94 seville have an aux. tranny cooler?

So if the flow is into the bottom of the rad then I presume it would then flow out of the top. You said you opened the top cooler line on the rad. So was the flow coming out of the rad and if so how did you catch the fluid?

The top rad cooler line in my 92 sts is connected to the bottom aux cooler openning.

[Barry94]

does your 94 seville have an aux. tranny cooler?

So if the flow is into the bottom of the rad then I presume it would then flow out of the top. You said you opened the top cooler line on the rad. So was the flow coming out of the rad and if so how did you catch the fluid?

The top rad cooler line in my 92 sts is connected to the bottom aux cooler openning.

I have an aux. cooler on my '94. Here is the flow.

Hot fluid from the trans enters the rad at the bottom, then out the top of the rad to the top of the aux cooler.

Bottom of the aux cooler back to the return line to the tranny.

I also use the method of starting the engine to pump the trans fluid out.

I have a brass hose fitting that connects to the top of the rad hose cooler fitting with a long rubber line attached.

Place the rubber line in a bucket, start the engine, and a few minutes later the transmission is mostly pumped dry.

You now can remove the pan with very little mess, and you also do not need to remove the plug to drain the side pan.

This method works on any car.

Barry

Note: If anyone is adding an aux. cooler, you can purchase from the dealer a small "U" fitting that screws into the top of the rad. to direct the line to the front grille area. It's only about 3" long.

What's nice about it, is that it is a tight "U" and takes very little space.

The fitting is from a '93 Olds 98 with factory installed trans cooler.

Also, most of the discussion in the past here regarding aux coolers is that you don't need one.

That may be true, however I always add one to my cars anyway. Seems like good insurance.

[shenKing]

Thanks again for your input.

I am back to square one Looks like the 92 tranny fluid flow direction to the rad is reverse of the 94. Can someone who is familiar with the 92 sts put this to rest

[shenKing]

ok the verdict is in.

I unhooked the upper tranny cooler line at the radiator and from what I could understand from the manual, the flow seem to go from the upper line into the radiator. So hooked the plastic hose to the upper line end and started the engine and waited... nothing...then looked down at the radiator and what a holy mess. Fluid was shooting out from the radiator opening! Just what I was trying to avoid.

Anyhow, for the benefit of those who are contemplating to purge the tranny fluid and unsure of which end to hook the drain hose, Jschunke and Barry94 was right. Use the upper radiator end and not the cooler line end. Adallak, the manual is indeed confusing...don't know who wrote it.

Barry94, what kind of a connector did you use. I just barely managed to hook up a 5/8" pipe thread nylon connector to the rad end. I think I cross threaded it (lucky it was nylon). Is your connector of pipe thread or of different spec?

The drained atf looked pretty wierd even though I just changed it a month ago. It does not look as clear as the new one and I am wondering if it is because of air mixing with it. After letting it sit for a few hours seem to clear the murky look.

Anyway, I have replaced Mobil synthetic atf with the cheapest atf (Chevron). Used about 14 quartz of it. Waiting to see if my old tranny is going to be happier.

[adallak]

Adallak, the manual is indeed confusing...don't know who wrote it.

shenKing,

Thank you for the clarification. Indeed the oil return line appears to be actually oil sending one... They had better to use an arrow instead of words . Hopefully your tranny will do better with new ATF. Keep us informed!

[Barry94]

Barry94, what kind of a connector did you use. I just barely managed to hook up a 5/8" pipe thread nylon connector to the rad end. I think I cross threaded it (lucky it was nylon). Is your connector of pipe thread or of different spec?

Connectors to the rad.

Not to make this too confusing, GM uses two sizes of cooling lines. Not sure of the actual sizes. I think 5/16 and 3/8.

Cadillacs use the larger size.

For the smaller size I have a brass fitting that came with a trans cooler kit. It's made to screw into the rad. and has a barbed hose fitting.

For the larger lines (Cadillac), I used a flare nut and a short piece of pipe and flared the end. It is a replica of the cooler line, only it's about 1" long, Just need to push a piece of rubber hose on it.

Hope this helps.

Barry

[shenKing]

Thanks Barry. You know, I just replaced the upper cooler line before I put in that Mobil synthetic ATF. Should have saved it for times like this.

Just to clarify: when I said it was 5/8" pipe thread, it's the measured OD of the thread and I think that's not how it is specified in the hardware store. So 3/8" is probably the right figure.