What size fitting will thread into trans cooling port at radiator?

gmcman

Original poster
Member
Dec 12, 2011
4,656
Looking to flush the fluid, I have read that it's a 3/8 inverted flare but what will fit without causing a leak?

Is there a gas fitting at home depot that will thread in there or similiar?
 
Dec 4, 2011
518
gmcman said:
Looking to flush the fluid, I have read that it's a 3/8 inverted flare but what will fit without causing a leak?

Is there a gas fitting at home depot that will thread in there or similiar?

If you just want to disconnect to drain you better check VERY carefully. Mine is a special GM fitting with a hair-clip retainer. Pull the hair-clip and the tube pulls out of the port. Put the hair-clip back in, insert the tube and push, it will lock in.

If you are looking to add a tranny cooler, PCMforless sells stubs for these with flared screw on fittings. (I believe). This is for folks who don't want to cut the line and then hose clamp the rubber hose to it. On mine I added tube to flared fittings on one end and hose to flared on the hose.
 

gmcman

Original poster
Member
Dec 12, 2011
4,656
What I'm looking to do is attach a hose barb to the output of the cooler. You can pull back the rubber sleeve and unscrew the fitting.
 
Dec 4, 2011
518
gmcman said:
What I'm looking to do is attach a hose barb to the output of the cooler. You can pull back the rubber sleeve and unscrew the fitting.

I'm sorry but I may not comprehend what you are doing. Let me state it my way. The tranny pipe exiting the cooler in the radiator (drivers side is exit, pass is input) you want to attach a barbed fitting to.

If this is correct then:

:eek: Sorry the only picture I could find was on the OS :eek:

My tranny cooler hook up with pics - Chevy TrailBlazer, TrailBlazer SS and GMC Envoy Forum

Anyway the black plastic hat pulls back towards the cab and then there is a Hairpin that you need to extract with small screwdriver and needle nose pliers. After the hairpin is out you can then pull the pipe straight out. The only way to put a hose barb on here is to cut the line and put a compression fitting (3/8" I think) to hose barb (your choice of size).

Have I got it or am I still flailing around in the dark? :confused::confused:
 

gmcman

Original poster
Member
Dec 12, 2011
4,656
Basically remove the entire fitting and insert a male threaded hose barb into the cooler.

By pulling back the rubber sleeve you an get a flare wrench on it and from what I have gathered you can rotate the fitting with the line still connected.

I just don't know what thread style works.
 

gmcman

Original poster
Member
Dec 12, 2011
4,656
Yes, I want to remove the nut from the radiator, I didn't think the cooler inside the radiator would fall if I remove the nut, can't imagine it would.

No drain, just one inlet and one out at the bottom of the radiator. It's easier to slip a hose over a barb than the cooler line.
 

Wooluf1952

Member
Nov 20, 2011
2,663
Milwaukee, Wisconsin
lint said:
I think if you take that nut off the cooler will come loose in the tank, I could be wrong, hopefully someone will chime in and confirm You are talking about the nut in the pic. with the black clip around it My tranny cooler hook up with pics - Chevy TrailBlazer, TrailBlazer SS and GMC Envoy Forum ''there is a quick release fitting on it now''

^^ That is true.

Those nuts (one on each end) hold the OEM trans cooler in place and keep the coolant sealed in.
If you only remove one at a time, you might be safe.
 

lint

Member
Dec 4, 2011
155
pic of cooler , what the nut screws into. if the seal comes loose antifreeze will leak in.
 

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Dec 4, 2011
518
gmcman said:
Basically remove the entire fitting and insert a male threaded hose barb into the cooler.

By pulling back the rubber sleeve you an get a flare wrench on it and from what I have gathered you can rotate the fitting with the line still connected.

I just don't know what thread style works.

lint said:
I think if you take that nut off the cooler will come loose in the tank, I could be wrong, hopefully someone will chime in and confirm You are talking about the nut in the pic. with the black clip around it My tranny cooler hook up with pics - Chevy TrailBlazer, TrailBlazer SS and GMC Envoy Forum ''there is a quick release fitting on it now''

gmcman said:
Yes, I want to remove the nut from the radiator, I didn't think the cooler inside the radiator would fall if I remove the nut, can't imagine it would.

No drain, just one inlet and one out at the bottom of the radiator. It's easier to slip a hose over a barb than the cooler line.

Do NOT remove the nut. Lint is correct it holds the cooler in the tank. If you take off the nut the antifreeze will leak out of the radiator.

If you want a hose barb you have to to cut the line and install a compression fitting on the pipe/tube with a hose barb on the other end. I couldn't find one of these so that means you go from compression to Female pipe thread and then from Male pipe thread to hose barb. Or as I suggested earlier put the hose over the pipe/tube and hose clamp it on.

Still not sure what you are doing with the other end. :confused::confused:
 

gmcman

Original poster
Member
Dec 12, 2011
4,656
RedEnvoyDenal said:
Still not sure what you are doing with the other end. :confused::confused:

Thanks......glad I didn't find a fitting, I didn't know it would break a seal.

The other end will be attached to the cooler, the one I remove will just hang there since it draws suction. I will be refilling through the dipstick tube.

This is for a fluid exchange.
 
Dec 4, 2011
518
gmcman said:
Thanks......glad I didn't find a fitting, I didn't know it would break a seal.

The other end will be attached to the cooler, the one I remove will just hang there since it draws suction. I will be refilling through the dipstick tube.

This is for a fluid exchange.

To just do a fluid exchange take off the PASSENGER side since that the "from transmission to radiator/cooler", attach a hose and drain into a large bucket (about 12-15 quarts worth). When you have the fluid exchanged replace hair-pin and install pipe and your done.

I am not quite sure how you plan to exchange the fluid but using this pipe a drain will exchange all the fluid vs dropping the pan which will only get about 5 quarts. There are several different opinions on how this should be done. I have disconnected the line and used the pump in the tranny to expel most of the fluid (note some people do NOT advocate doing it this way). I then refilled the tranny via the dipstick tube. I have had not issues at all. Would not suggest letting run almost dry for long and only at idle speed because lubrication will be at a minimum.

Another method is to fill the dipstick at the same time as it pumps out the pipe. Like I said the system takes about 12-13 quarts you should probably have about 16 on hand to do it this way. You should always have a couple extra anyway that can be returned if you don't need them.

One other suggestion if you decide to change fluid (always a good idea) use synthetic (my opinion) and drop the pan and change the filter at the same time. (if you drop the pan put a bung in, so next time it is easier to drain.

good luck shouldn't be to hard. :thumbsup::thumbsup:
 

gmcman

Original poster
Member
Dec 12, 2011
4,656
I appreciate all the input.

I plan on doing this a little different by flushing the cooler as well. I see a larger nut on the cooler, that's not the one I plan to remove, is that the one that can loosen the cooler or is it the smaller nut?
 
Dec 4, 2011
518
gmcman said:
I appreciate all the input.

I plan on doing this a little different by flushing the cooler as well. I see a larger nut on the cooler, that's not the one I plan to remove, is that the one that can loosen the cooler or is it the smaller nut?

Not sure what two nuts you are looking at. As far as I know there is only one nut per side and they hold the cooler in the tank. I wouldn't worry about the oil in the cooler since it is very small amount considering how much is in the system. Check out the link I sent earlier, is there not just one nut per side and black sleeve cover?

Now I think I understand why you are trying to connect something to the output of the cooler. Neater/Cleaner to just use the passenger side and not worry about the oil in the cooler. If you get anal like I sometimes do then just put a blast of air (short) into the input side, but cover the output since it will come out quickly. Again I wouldn't worry about it.
 

Dad-O-Matic

Member
Dec 5, 2011
228
RedEnvoyDenal said:
To just do a fluid exchange take off the PASSENGER side since that the "from transmission to radiator/cooler", attach a hose and drain into a large bucket (about 12-15 quarts worth). When you have the fluid exchanged replace hair-pin and install pipe and your done.

I was thinking as I was reading this, would this work?:

1) Get two buckets, one VERY clean with brand new fluid (buy it by the gallon, cheaper and easier to pour in the bucket) and one for the old fluid.

2) Put the discharge hose (passenger side) in the old fluid bucket, intake (driver side) in the clean bucket and there you go. As the old fluid is pumped out the new fluid is pumped in. When the fluid runs nice and red on the discharge side stop the pumping process.

3) Drop the pan, replace the filter and then top off the fluid. Done

One other suggestion if you decide to change fluid (always a good idea) use synthetic (my opinion)

Dex VI or equivalent is full synthetic and the only recommended one to use anymore.

drop the pan and change the filter at the same time. (if you drop the pan put a bung in, so next time it is easier to drain.

Buy a Dorman pan part number 265-811, $40 on Amazon and already has the drain plug.

http://www.amazon.com/Dorman-265-811-Transmission-Oil-Pan
 

Mark20

Member
Dec 6, 2011
1,630
Does the return line pull enough suction to draw up from a bucket?

That fitting will give you a leg up on installing an external tranny cooler.

And going a little off topic, that tranny cooler in the radiator is far more substantial than I thought it was.
 
Dec 4, 2011
518
Mark20 said:
Does the return line pull enough suction to draw up from a bucket?

That fitting will give you a leg up on installing an external tranny cooler.

And going a little off topic, that tranny cooler in the radiator is far more substantial than I thought it was.

Not sure if the Gerotor pump in the Tranny is a push type or pull type.

Not to be argumentative but I think the only fluid that has to be GM is for the Transfer Case. All other parts (front and rear diffs, tranny) can use anyone's product. I prefer Amsoil for all my other fills.

Interesting idea to pull from a full bucket while pumping out to and empty one. Let us know how this works if you.
 

Dad-O-Matic

Member
Dec 5, 2011
228
RedEnvoyDenal said:
Not to be argumentative ...........

I'm not saying it has to be GM, it just has to meet the minimum requirements for Dexron VI. If it meets the Dex VI standard, that means GM has tested it and given it their "seal of approval", i.e. it won't violate your warranty. Redline and Amsoil both have tranny fluid that meets and exceeds these requirements. I personally will use Amsoil for my next fluid change.

The older TB/Envoys used Dex III, but GM no longer supports that standard, tests or provides oversight on the manufacturer of Dex III. If you buy Dex III for an older model, you have no idea if it's will even meet that old standard. Any one can slap a Dex III label on their tranny fluid, but without GM's stamp of approval it really is just another label. If it's made by a reputable company (Pennzoil, Valvoline, etc) it'll probably work just fine in the older tranny's but for only a couple of extra bucks a quart, why take the chance?
 
Dec 4, 2011
518
Dad-O-Matic said:
I'm not saying it has to be GM, it just has to meet the minimum requirements for Dexron VI. If it meets the Dex VI standard, that means GM has tested it and given it their "seal of approval", i.e. it won't violate your warranty. Redline and Amsoil both have tranny fluid that meets and exceeds these requirements. I personally will use Amsoil for my next fluid change.

The older TB/Envoys used Dex III, but GM no longer supports that standard, tests or provides oversight on the manufacturer of Dex III. If you buy Dex III for an older model, you have no idea if it's will even meet that old standard. Any one can slap a Dex III label on their tranny fluid, but without GM's stamp of approval it really is just another label. If it's made by a reputable company (Pennzoil, Valvoline, etc) it'll probably work just fine in the older tranny's but for only a couple of extra bucks a quart, why take the chance?

Sorry I will set up an appointment to get my eyes checked sooner. You are correct all replacement fluids need to meet or exceed GM Specs :thumbsup:
 

Mark20

Member
Dec 6, 2011
1,630
Do any of the auto makers certify or sample products on the market to see if they meet their spec's?
 

gmcman

Original poster
Member
Dec 12, 2011
4,656
lint said:
OK . if your trying to put a hose barb on the driver side,, You can you this. Fitting, 2000-up, some GM applications Fitting kits Makco Transmission Parts. but you would neat to cut the pipe then put a peace of hose on.

That's about what i'm looking for now...thanks. I tried to find a fitting to thread in the cooler but it's a phantom fitting for the most part. Not sure what other setups look like but here's mine, the large nut is what possibly holds the cooler in place, but the smaller nut is removable...nothing fell out of place.

Cheapest way is surely to attach a 3/8 hose onto the cooler line once you pull it from the quick-connect.
 

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