Archived transmission ATF check valve replacement part?

[KOwens]

Hello TDR gurus,



My '95 diesel ram sprang an ATF leak today and I'm in the process of fixing the problem that originated with the quick connect lines. Basically I've ripped out the old lines and connector fitting from the transmission (inlet and outlet) and the primary heat exchanger (engine coolant heat exchanger). The outlet and return connectors at the transmission are 1/4" male NPT, and the primary heat exchanger uses 3/8" male NPT. I have a auxillary transmission cooler coming to my dealer in the morning, which I will replace also, but these connections are simply hose clamps for 1/2" inside diameter hose.



What I've discovered is the pressure line from the transmission to the primary heat exchanger has a check valve in the steel pipe-to-hose-to-quick connect interface below the primary heat exchanger inlet. What a cluster of connections this mess is. I want to end up with something that resembles sanity when I'm done and not this cluster of connections at the heat exhanger.



My intent is to have new hoses made at HosePros in my area and completely replace the old quick connect fittings and metal tubing, but I'm not sure what to do about the check valve in the path between the transmission and the primary heat exchanger. Is there such a thing as a check valve with 3/8" male NPT on one end and JIC or SAE male on the other? This would make interfacing a hose to the check valve a snap.



I would like to get my truck running and back on the road tomorrow if possible, and could use any help on the best appoach to replacing the check valve while still achieving a clean cooler line replacement. If you have a solution, please include the part numbers or at least a source where I can get the parts needed.



Please help if you have the time.



Thank you, Kevin

 

[p-Bar]

You may want to try McMasterCarr
McMaster-Carr

 

[Joe G.]

Leave the check valve out. It is supposed to help with torque converter overnight drain, but has been ineffective at doing that. I have been without that check valve for some time with no adverse affects. All my cooler lines are hose. One thing is that where both lines cross from one side to the other in front of the transmission pan is not necessary. Only one of them needs to go to the other side. I routed the other one to the front without the cross over craziness.

 

[KOwens]

Thanks Joe

Thanks for the info on the check valve Joe,



Good to know it is just another Dodge decoration with little or no real value in the system. By the way, my transmission temp sensor has been replaced with resistor for years with no problem either. Got tired of replacing them as well.



What hose did you end up using on your cooler line replacement? Is the Aeroquip FC332 a good choice? My hose guy in my area tells me only certain types of hose can be clamped using hose clamps and it looks like that is the only way to connect the auxillary cooler up front of the radiator to the new hydraulic hose I'm planning on installing. If you remember what you used, I could use some advice in this area. I want to be sure it handles the pressure and the temperature and can be clamped at the aux cooler.



Also, I am looking at using 90 degree JIC fittings on the transmission input and output ports. Did you do something similar to keep the bend radius under control getting the hose headed for the aux cooler and the primary cooler (coolant heat exchanger)? Just wondering.



How about thread sealant on the threads for the transmission and primary heat exchanger/cooler? What is best for sealing ATF anyway?



I agree with you on the routing of the hose from the primary cooler to the aux cooler. I was measuring that run last night while I was under the truck and wondered the same thing; why did they run it back around in the first place. Makes no sense to me, but hey lots of stuff on this truck makes little or no sense at all.



Anyway, thanks for the info and hopefully you can answer my questions about your hose replacement as well.



Take care and thanks again.



Kevin

 

[Joe G.]

I don't remember the hose type. There is very little pressure in the cooler lines because the ATF just dumps in the trans pan. I asked the hydraulic guy for some hose that could stand hot oil because pressure is not a problem. I used barbed fittings and gear clamps. Here is a picture of how I did my front cooler line and temp sending unit. There are no tight turns because I used brass fittings where needed. The second picture shows the bottom of the heat exchanger. For the cross over hose to the heat exchanger below the exhaust manifold I drilled and tapped a hole in the bottom of the bell housing so I could mount a support clamp there. I didn't take a picture of that. I used the pan bolts that have a nut on them for the support clamps for the hose going forward. I think I had to move them to do that. It's been a while.

 

[KOwens]

Thanks again Joe

Thanks for the photos Joe, it really helps to see how you did your plumbing.



Looks like you used fairly small diameter hose for the barbed connections, but what did you do at the auxillary cooler out front? Seems to me it will require 1/2" inside diameter hose at this connection. Did you size it up with larger hose before making this connection? I know this is a tight spot also for this particular connection, and would like to know how you pulled that off.



Also good to know that pressure is not the real issue here. I was reading the flow test in my manual last night also and it sounds like the pump only delivers about one quart of ATF in 20 seconds time at idle, so it can't be moving very fast down those lines; and certainly not under very much pressure.



Getting back to the thread sealant, do you remember what you used on the NPT connections at the transmission and the heat exchanger? Just wondering.



Thanks again for the info and photos, it really helps me understand what to do.



Kevin

 

[Joe G.]

That's all 1/2" ID hose. The fittings a 1/4" NPT so smaller hose would work, but that would make the front connections a worse job than necessary. The front connections are a major PITA! No room for your hands. I managed to do it without having to splice hoses, but there were a lot of expressive terms used during that job. I use SilGlide to help with installing hose on barbed fittings. I get it at NAPA. I think I used anti seize for sealant but can't remember for sure. Might have used liquid teflon.

The transmission works by pressure differences so any pressure in the cooler lines is not helping.

 

[KOwens]

Thanks Joe

Sounds good, for some reason the hose looked smaller in diameter to me.



I will shop for something similar later today.



For the record, I am replacing the front aux cooler at the same time since this one has 257,000 miles on it and it is showing signs of corrosion on the cooling fins. So in my case, I plan to attach the new hose onto the aux cooler and then feed them through the opening as an assembly when I mount the aux cooler to the A/C condensor and front mounting brackets.



At any rate, now that I don't need to worry about the check valve and seeing your installation photos, this should be fairly pain free for me tomorrow.



Thanks again for the help, I do appreciate your time.



Kevin