Ah, transmission cooler lines.
There is three types/designs of cooler lines and two different transmission types.
The A727 (and A518 and other 4-speed versions based off the A727) are slightly different from the A904/A998/A999 (and A500 and other 4-speed versions of the A904). The difference is the exit/entry point of transmission and bent a bit differently due to shape of bell housing.
The cooler lines are somewhat soft and is not hard to bend. In many cases, it is not hard to bend them to fit between the two transmission types – but sometimes there is just not enough line to make it fit. If changing transmission types, I would say there is a 50/50 chance (based off existing experience) that existing transmission cooler lines will fit and work with some minor bending of existing lines or won’t fit.
I have installed transmissions both directions (A904 in place of A727 and vice versa).
Other versions of the transmission cooler lines are:
In early ‘80’s (not sure when) Chrysler went from having a nut/flare connector directly to the radiator to having a short piece of hose between the cooler lines and radiator.
Also, the police and HD towing packages got an external cooler mounted in behind the grill, and one cooler line is different, and a third line is added.
The rubber hose was added because of engine vibration. The vibration tends to crack the cooler lines, sometimes. The short rubber hoses (at radiator) eliminated that problem.
Now with what I said above, Chrysler changed the cooler lines each and every year. They either added a small bend here or routed it this way instead of that way.
The cooler lines on my ’77 wagon bends at the front of transmission, goes underneath the engine oil pan to passenger side of car, then goes to front of engine. Most of the cooler lines, they run along the engine oil pan flange, under the starter and on drivers’ side of engine.
Of all the transmission cooler lines I have worked with, from early ‘60’s to mid ‘90’s, a person can generally take the entire cooler line system (lines, fittings, brackets, etc.) and transfer it to any other car line through the years with a couple of exceptions:
- Rubber vs. nuts to attach to radiator
- /6, small block and big block won’t interchange without a ton of extra bending (pretty much the entire length) – so just not worth the effort.
I hadn’t had any issues interchanging cooler lines between different body’s before (when needed). I had stalled a ’74 New Yorker (C-body) cooler line into a big block A-body without any issue whatso ever (as well as other examples).
Transmission cooler lines are under low pressure (6-10 PSI) for non-lockups and much higher under pressure (80 PSI+) on lockup transmissions (which came out mid-year ’78).
It is time consuming, but I have even made a replacement cooler line myself, but it took me a few hours to do so. I do recommend purchasing a set if a set is needed.
https://www.inlinetube.com/pages/product-list?category=4839198639561824844#?f=47176767495174200|169870010550578016|&p=2
Part number PRT7801 (1976-80 Road Runner/Volare 360 727 5/16”, 2 piece) $55.00
https://www.manciniracing.com/maratrcoli2p12.html
Part number ILTBBT7401 (74-76 A-body small block) $45.00 (not an FMJ but should still work)
There might be other sources as well.
One piece of advice is if you are going to use robber to connect to radiator with (what I recommend) and you have a lockup transmission, I do highly recommend using a line that has a bubble end on it – to prevent the hose from popping off when at pressure.
Also, be sure to use rubber hose rated for higher pressure (ie: fuel injector hose, etc.) for regular 5/16” fuel hose can’t take the high pressure a lockup transmission tosses at it. A non-lockup transmission doesn’t care what kind of hose you use.
88_AHB, you might find one of the above sources to be a lot cheaper than making it as you have described.
Correction: i just saw that you did.
BudW
