Stripped 727 Transmission cooling line

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70Dart340V8

70Dart340V8

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Ive come to seek the help of anyone that may have had the misfortune of having this happen or anyone with good advice. When I was installing new tranny cooling lines, I was trying to wedge the shift linkage past the pressure line. I guess by pushing a little too hard on the line (near the fitting) it was enough to strip the threads out of the side of the transmission. I didn't think I was even pushing that hard...so now I'm at a loss...the only ideas I can think of off the top of my head is putting a heli coil in the now stripped hole or possibly rethreading it and putting a larger fitting in it. I feel like the first choice would be easier and wouldn't risk getting the metal shavings inside the transmission (as much) as threading a new hole. my only concern is that Im not sure if a heli coil would work well for a fluid coupling, especially a pressure line...
 
Why wouldn't it. If you put some sealer around it before installing it, Heli-Coils are pretty robust. I've heard of guys using them for head bolts that take 85 ft*lbs of torque successfully...
 
A helicoil is going to be just as big a risk for chips as you still have to drill larger and re-thread the hole. Sorry, I'm not familiar enough with TF to recommend, depending on what port, you might be able to SLIGHTLY pressurize another port on the transmission, and use heavy grease to "retain" the chips.


I don't understand what you mean by "stripped." Did you break the adapter that screws in, or ruin the threads while attempting to screw it in? If the latter, you might be able to chace the original threads and clean it up.

Last if you are lucky enough that this is the OUTLET side of the cooler ports, you could flush it, although messy, with a "quick start" of the engine so to speak. Lots of rags. Lots.
 
Yeah, I'm lost too. There's a brass fitting there that sticks out, to receive the steel line. I can see breaking the fitting,allbeit with difficulty, but it"s hard to imagine stripping out the threads in the case, in the manner described.
An Easy-Out will extract the broken-off brass chunk.
 
AJ/FormS said:
Yeah, I'm lost too. There's a brass fitting there that sticks out, to receive the steel line. I can see breaking the fitting,allbeit with difficulty, but it"s hard to imagine stripping out the threads in the case, in the manner described.
Click to expand...

I was thinking the same thing when reading it. I just can't imagine that happening. The brass adapter should break long before pulling the threads out of the case, unless they were already trashed to begin with
 
Use a thread insert, not a helicoil. A thread insert is solid, a helicoil is a wound thread. To prevent chips in the trans pack the tap flutes with grease.
 
Not sure I am following. Are you talking about the pressure line, the front most line? Was the line connected to the brass adapter when this occurred? Or was it loose and just banging around the tapped transmission hole?

If it was loose, could just be the first few threads on the fitting are buggered. If this is the case run a bottoming tap into the female fitting and replace the brass fitting. If it is truly stripped out, carefully stuff a cloth patch into the port and tap the hole for a larger hole (you will need to buy another brass flare fitting). After it is tapped, use a pair of long tweezers and pull the patch back out. I'm not sure where the pressure port goes or if you can get to it from inside.
 
the only way this makes sense to me (if I'm reading it right) is if the fitting was not inserted into the transmission very far
and, if that is the case, there should be plenty of thread left in there for you to screw a new fitting in

I would look into that and hope for the best
 
The holes in the transmission case that accept the brass fittings for the cooler lines are tapped NPT, or pipe thread. This is not a straight cut thread like on a bolt, but is tapered. I have never seen any kind of thread insert or helicoil repair for pipe threads. The way I see it you have three options if the female threads in the case are damaged.

1- drill and tap the hole to the next size pipe thread being careful to keep swarf out of the transmission.

2- drill and tap the hole to the next size hydraulic fitting, this will require an o ring with the fitting to seal.

3- weld up the hole and re drill it to the correct size pipe thread.

My 2 cents.
 
d55dave said:
The holes in the transmission case that accept the brass fittings for the cooler lines are tapped NPT, or pipe thread. This is not a straight cut thread like on a bolt, but is tapered. I have never seen any kind of thread insert or helicoil repair for pipe threads. The way I see it you have three options if the female threads in the case are damaged.

1- drill and tap the hole to the next size pipe thread being careful to keep swarf out of the transmission.

2- drill and tap the hole to the next size hydraulic fitting, this will require an o ring with the fitting to seal.

3- weld up the hole and re drill it to the correct size pipe thread.

My 2 cents.
Click to expand...

I thought that too,, when I first read the thread,, but googled it,, and learned of several "repair methods"..

EDIT..http://www.threadtoolsupply.com/18-27-npt-professional-helical-insert-repair-kit.html

https://www.bing.com/search?q=pipe+thread+helicoil&pc=MOZI&form=MOZSBR

cheers..
 
For pipe thread a thread insert would be called a reducer bushing. I believe the fitting broken is a 1/8 NPT. Drill it out to 1/4" NPT and install a bushing like pictured or get a flare fitting with larger male NPT end.
 

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This just happened to me today. Putting my new transmission lines in and noticed the brass fitting was loose. Went to tighten it down and it wouldn't snug down. Backed it out and noticed that the first 1/4" of threads of the case were stripped out. I have access to a pipe tap to chase the threads. What are the chances of buying a new fitting and sealing it with some sort of epoxy sealer? Here's the offending fitting.

E7F341D8-98A9-461C-AA06-E2573BFEE181_zpstyquhweh.jpg
 
That fitting does not look right. There's too much sticking out of the pipe-thread end.
The way those fit in the case, if you are careful to not tap too far down, I think it will work fine with a new correct fitting and no sealer at all. At worst, you might have to spot face the entrance to make room for the hex, and the wrench/socket.
 
AJ/FormS said:
That fitting does not look right.
Click to expand...

That wouldn't surprise me at all. This transmission was a real bastard of parts from different vehicles held together with bubble gum and bailing wire. I'll be buying the correct fittings from Mancini tomorrow.
 
67Dart273 said:
None of this is applicable to "pipe" threads which are tapered.
Click to expand...

Sorry,, first link incorrectly pasted,,, second one's accurate, - listing several links..

this is what I meant to post,, tapered..?, who'd a thunk..?.. lol

Helical Insert Specs:

Internal Thread Size: 1/8-27 NPT
Length: 0.273"
Material: 18-8 (304) Stainless Steel
Type: Free Running
Tap Size: 1/8-27 NPT STI
Drill Size: 3/8" (not included in kit, sold separately)

Quickly and easily repair stripped or damaged threads, or create stronger original threads in die castings or plastics with our Helical Screw Thread Inserts. Coil tension securely holds the insert in place without undue tension on the surrounding material. The inserts are vibration and impact resistant so won't strip or seize. Made from corrosion resistant stainless steel, they offer a wide temperature tolerance.

Helical Inserts are often known by the brand names Helicoil or Recoil Screw Thread Inserts. Our Precision Thread Helical Inserts are interchangeable with other brands of inserts and tooling. Rest assured you'll enjoy an easy and accurate transition to our Precision Thread Helical Inserts from Chrislynn

http://www.threadtoolsupply.com/18-27-npt-professional-helical-insert-repair-kit.html.

AJ/FormS said:
That fitting does not look right. There's too much sticking out of the pipe-thread end.
The way those fit in the case, if you are careful to not tap too far down, I think it will work fine with a new correct fitting and no sealer at all. At worst, you might have to spot face the entrance to make room for the hex, and the wrench/socket.
Click to expand...

^^^ xx2
 
Here's the ones Mancini sells. I don't see much difference other than the very tip? Mine were probably generic parts store fittings. I'm ordering the Mancini ones this a.m.

auto-trans-cooler-fitting-each-4.gif
 
Mancini's probably are generic fitting you could get from a hydraulic hose specialist..Not all fittings are the same, depending on the brand, one might screw in a little bit more than another.
 
I ended up just drilling the hole to 5/16 and using a 1/4 pipe tap. I used a 5/16 flare to 1/4 NPT fitting. It's a paint in the *** getting the drill and a 5/16 drill bit in there. I had to remove the torsion bar, the small piece of brake line running from the proportioning valve to the metering valve and I also had to cut about 1/4" off the base of the drill bit. After all that I was just barley able to fit it in.
 
BrianT said:
Here's the ones Mancini sells. I don't see much difference other than the very tip? Mine were probably generic parts store fittings. I'm ordering the Mancini ones this a.m.



The generic ones should have been fine, and frankly, that is all the Mancini appears. " I don't see much difference other than the very tip? "

Are you talking about the right hand side of the photo of your original? This does not appear normal to me. That is common pipe thread, any of them should look more like the Mancini photo you posted.
Click to expand...
 
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