Engine/Transmission (1994 - 1998) Hydraulic trans cooler line conversion

[Willys]

I had a transmission cooler line fail this week on my '95 that left me stranded. The fitting failed- it was either compression or flared, haven't taken it apart yet. I bought goodyear push lock hydraulic hose to replace it. Has anyone else used the push lock or insta-lock hose and matching barbed fittings without clamps? The guys at the hydraulic shop said it is good for over 1000 psi without leaking, and that putting clamps on it would cut it.



I'm just going to replace the one line for now and see how it goes, if I like it I'll replace all the lines on both trucks. Having a truck break in the middle of the day makes me lose money while working- having a backup truck at home helped, but I'm trying to eliminate as many things that can cause failure as possible. Both trucks are well over 200k miles, but I don't see any reason they shouldn't be reliable enough to make a trip anywhere, anytime just like a new one... with a little preventative maintenance.

 

[KMott]

I replaced all my original lines with 3/8 ID hydraulic hose (not sure what brand) and barbed fittings. I havent had any problems with leaks at all, and i dont see why it shouldnt last forever. Cost was around 80 dollars. I had bought the new lines from chrysler (around 500) but they didnt fit right and didnt seem any better than the older ones. I also would had to have spent another 300 dollars for the updated hoses going to the transmission cooler. So i just returned them and picked up the hydraulic hose. I used Joe G's idea of eliminating the temperature sensor in the line. I picked up a 1k resistor from radio shack, and stuck it between the terminals on the the plug that goes to the temp sensor. When we hooked up the scan tool it was reading that the trans oil was 74 degrees C, which allows the transmission to operate properly. (you will get tc lockup right away, instead of having to wait for the oil to heat up)

By eliminating the sensor, it makes the job much easier. You just cut three lines to length, and have your barbed fittings threaded into the transmission, secondary cooler, and adaptor fittings to go from the t-cooler line size (1/2 inch to whatever ID hose you choose)

I used clamps on the hoses, but it wasnt necessary, i dont think they are doing anything, as the lines push on very tight.

Hope this helps!

 

[Willys]

Were they push lock or regular barbs?



I already put a resistor in the temp sensor connector as it was downshifting into 3rd at random recently. Then I eliminated the defective TPS as well... but that's another thread.



I still need to add a fitting in somewhere, as I really should put a trans. temp pickup for a gauge in soon. Unfortunately, I won't have one until later. I might pick up a few extra fittings before I put it together so I can have the fitting already in, and just plug it until I get the gauge set. Only problem is I don't know what size fitting the gauge pickups are.



I have 1/2" hydraulic hose and barbs since I didn't know for sure what size the lines are and 3/8" looked kind of small. I figure it can't hurt to have it a little bigger.

 

[smokinrod]

I used all push lock on mine , never had a problem. those things will never come apart

 

[Joe G.]

Only problem is I don't know what size fitting the gauge pickups are.

Build it for 1/4" NPT for the gauge sensor. If it turns out to be 1/8" NPT you can use a bushing to reduce it.

 

[smokinrod]

just buy a DD oil pan , it will have alot more fluid for better cooling and it has a spot in it for the sending unit.

 

[Cummins360]

What do these push lock fittings look like anyways?? Mine are leaking and I need to replace mine soon. (Stock steel lines)

 

[Joe G.]

Here is the way I did my temperature sensor. I don't think the pan is the right place for it. I used a nipple to provide a little clearance beween the T fitting and the machinery so I have room to work on things if I need to. No leaks since changing to hose.



#ad

 

[Willys]

Thanks for the pic Joe, that's pretty much what I had in mind.



How did you route the lines? I don't like the idea of routing them under the transmission and clipping them to the oil pan bolts(like the stock steel ones). I'm thinking about slipping some split heater hose around it and sliding it over the top of the transmission. I figure even then it still needs to be secured some way since I don't want any more leveraged pressure on the fitting than I can help.

 

[Joe G.]

The line that connects to the cooler under the manifold goes across between the engine and the transmission. I have one line on each side of the engine instead of both crossing over. I used rubber lined clamps to hold the lines in place. That way I don't have any problems with the hoses rubbing the edges of the support clamps. I used the pan bolts with the nuts on them to mount the clamps on each side of the engine. Plus some others where needed. The idea is to prevent as much metal to hose contact as possible. I drilled and tapped a hole in the bottom of the bell housing to support the hose that crossed over so that it is up out of the way but not touching anything. The support clamps are snug, not tight on the hose. No signs of any wear anywhere so far. AND NO LEAKS!!!

 

[sdstriper]

The cooler lines on the 1st Gen trucks are 5/8 steel tube, don't know about the newer year models. The picture Joe G has posted is the best location for accurate trans temps, pressure out, temps right from the TC. Go to DTT's site and link to their forum, I have no affiliation with them and could not afford much of anything he sells but I will not complain about the info available there. I cannot believe the number of guys I know or have seen or heard about that restrict the cooler circuit with small aftermarket aux. coolers or hose/tube that is less expensive, smaller and too small ID etc. , including myself until I was having issues and started to study up to handle the problem. How many times have you heard get a bigger pan and put a gauge in there, more times than I can remember, your gauge in the pan is fluid that just returned from the cooler(s). And if you cut out the factory cooler and/or add one with 3/8 lines, restrict the cooling circuit with smaller tubing it's only a matter of time before you are faced with the expense of a rebuild, especially if you tow, even stop and go traffic in hot climates. Just my . 02 cents worth...

 

[Willys]

So you don't think 3/8" ID is large enough? I replaced the broken one with 1/2" ID but think I'll go ahead soon and replace all the lines on both trucks with 3/8". I'll look into the DTT site some more before I do it, I guess it couldn't hurt to have them all 1/2" .



BTW, the leak was from a broken fitting in the same spot as Joe's picture. The broken fitting was the updated compression fitting from dodge. Someone must have monkeyed with it and tweaked it, and the vibrations finished it off. An easy out pulled the broken end out.

 

[Joe G.]

I think you are ok with 3/8". Remember the fittings are 1/4" NPT. That's where the flow restriction is, not in the lines.

 

[sdstriper]

So you don't think 3/8" ID is large enough? I replaced the broken one with 1/2" ID but think I'll go ahead soon and replace all the lines on both trucks with 3/8". I'll look into the DTT site some more before I do it, I guess it couldn't hurt to have them all 1/2" .



BTW, the leak was from a broken fitting in the same spot as Joe's picture. The broken fitting was the updated compression fitting from dodge. Someone must have monkeyed with it and tweaked it, and the vibrations finished it off. An easy out pulled the broken end out.

Was it the trans case cracked or a just fitting? I believe Sonnex makes a repair kit for the case if so.



It was the downsize plumbing that caught my attention. It is a 1/4 reduction, considerable percentage, look into flow numbers with a reduction like that. Like I said, my . 02 for what it's worth.

 

[Willys]

It was the line fitting that was broken off in the hole in the transmission. I did see a thread with a p/n for the Sonnax kit, thanks for mentioning that, it always helps to have as much info in these threads as possible for future newbs.



Another question that has come to mind is the heat rating of the line. The one I have now(Goodyear pn ????), I can't find a reference for online to see the heat rating. I have found other lines that I was considering with a water and air rating of 180/165 degrees and about 220 for oil, degrees F if I recall correctly. Since I am buying enough line for both trucks, I'll get some extra to replace the old cheap air hose I have for my OBA system. The york compressor can get pretty hot so I need a line that can take quite a bit of heat. Do y'all have any recommendations for a quality low pressure(300 psi), high temp line(300 F) that is affordable?



- This is the link for the thread with the Sonnax p/n.

https://www.turbodieselregister.com...1&pp=15&highlight=Transmission+connector+leak

Sonnax #22000-01k

 

[sdstriper]

Affordable? Leave it to Chrysler to make your day when it comes to that, sometimes I wonder why I have always been a Mopar fan.



Most of the affordable hose and fitting info I have seen is out of that range or pushes the envelope of it. Teflon etc is what I see that is politically correct so-to-speak. And @ $11/ft locally I have another attitude problem when it comes to Chrysler... Here's the thing, 5/8 is not an option when you look at the specs. That's another reason you see plus or minus use, JCI 37* fittings are correct for the application, 3/8 and 1/2 and 3/4 hose, line etc. Allison uses 3/4. If I want to splice our hardline with tube connectors, put a piece of hose in or add another cooler etc. , my option is 1/2 or 3/4 for chemically compatable hose 300*+ high temp and pressure, then you get to juggle adapters. For what Teflon hose and fittings costs I would buy the flaring tool and bender and use steel tube, option to flare tube for future use then too. I better mention that I am not saying the smaller stuff is the total kiss of death, it works, plenty will testify to it. I want the correct dia. hoses or larger, and for the correct temps and pressures. It will be very cold here before too long and I don't like surprises involving unplanned downtime...