Leaking ATF Fluid after installing Thermal Bypass Valve

[Bob Johnson]

I replaced the thermal bypass valve on my 66RFE and it hasn't stopped leaking since. I used good quality ATS brand.

When I first installed it, I did not torque the lines very tight. I think instructions said something like 27 inch pounds. The thing leaked like bad, so I tightened them more and it leaked less. So I tightened them again and they stopped leaking, so I thought. See pic. It is leaking out the side of the lines that do not have the clips on them.

I towed my camper today and noticed that there was fluid all over the passenger side of my truck. Looks like about a quart leaked out for a 100 mile trip. It wasn't leaking when I left home.

My question for you guys is, do I need to tighten the lines more? It's already very tight, I really don't feel comfortable tightening it any more unless I'm supposed to. It's already way over the 27 inch pounds they called for in the instructions.

Also, I topped off the fluid. I'm worried that since the leak started after I started towing, is it going to get worse on the return trip home? I plan on keeping an eye on the fluid level going home (stopping periodically to check it).

 

[BenchTest]

I don't have any experience with this unit, but I'd venture to say that something is compromised in the line or the unit itself to continue to leak when you have tightened way beyond spec. Are those flared fittings, o-rings, or ?

 

[White six four]

I installed a revmax one on my 66rfe and the bottom line would seep fluid. Not enough to drip but it would be wet. Anyways I put teflon tape on the threads on that line and haven't leaked since. Scrolling through an old post on here I read someone else had to do it also.

 

[Dodge 1500 4X4]

Are you using a line wrench to tighten that fitting, being a flared fitting, you shouldn't need any other sealant unless the flair is damaged.

 

[Bob Johnson]

Are you using a line wrench to tighten that fitting, being a flared fitting, you shouldn't need any other sealant unless the flair is damaged.

I used an aluminum AN wrench at first then switched to a combination wrench when I had to tighten more.

 

[Bob Johnson]

I installed a revmax one on my 66rfe and the bottom line would seep fluid. Not enough to drip but it would be wet. Anyways I put teflon tape on the threads on that line and haven't leaked since. Scrolling through an old post on here I read someone else had to do it also.

Yes I would say it is just seeping. I have driven the truck about 325 miles since I changed the valve. It looks like the top line in the pic is the one leaking. I can see where the fluid has made it's way down the block from the top fitting.

 

[Bob Johnson]

I don't have any experience with this unit, but I'd venture to say that something is compromised in the line or the unit itself to continue to leak when you have tightened way beyond spec. Are those flared fittings, o-rings, or ?

The lines is flared with an o-ring on the end.

 

[Dodge 1500 4X4]

I used an aluminum AN wrench at first then switched to a combination wrench when I had to tighten more

So, you didn't use a Line Wrench, it grips the fitting nut on 3-4 sides so you can get a better fastening, used on hydraulic brake lines in the auto industry.

 

[BenchTest]

The lines is flared with an o-ring on the end.

I'm going to guess there is an issue with the flare/seat. With that type of connection, you shouldn't need any sealant (and typically shouldn't use). If you're in a pinch and have the means (sounds like you are away from home), dope those threads with a soft set compound and re-install/tighten. Teflon tape would suffice as well. Use extra diligence to not get compound (thread sealer) or Teflon tape into the fluid spaces. I would also add, inspect the o-ring for damage and being in it's proper boss location (recess designed specifically for the o-ring). Look for nicks/tears/flat spots on the o-ring.

 

[Bob Johnson]

I'm going to guess there is an issue with the flare/seat. With that type of connection, you shouldn't need any sealant (and typically shouldn't use). If you're in a pinch and have the means (sounds like you are away from home), dope those threads with a soft set compound and re-install/tighten. Teflon tape would suffice as well. Use extra diligence to not get compound (thread sealer) or Teflon tape into the fluid spaces. I would also add, inspect the o-ring for damage and being in it's proper boss location (recess designed specifically for the o-ring). Look for nicks/tears/flat spots on the o-ring.

Yeah, I'm away from home at a campground right now. I'm pretty sure it will make it home if the leak doesn't get worse. I do plan stopping by the auto parts store and grabbing a couple more quarts of ATF and checking the fluid level several times on the way home. I just don't want to mess with it while I'm on the road if I can help it.

 

[White six four]

Are you positive there are o rings for that side? I know they're on the circlip side. I can't remember since I did mine awhile ago. When I finally got around to fixing my seeping line I contacted Benny (oem parts guy) on here and he said it only shows them on the other side (circlip side). None on the back side of that thermal block with the threaded fittings. I'd assume both sides have o rings but again its been awhile. That's when I searched on here and saw someone else had to tape up the threads.

I was going to check and see if it actually had an oring but when I did that line the line itself stayed in there. So I left it kind of in fear if it was in there and partially damaged I would do more harm pulling the line back off.

If you think you lost a quart in 100 miles you have a leak. When I say mine was seeping I mean the bottom of the thermal block was barely wet and that was after a few thousand miles. Cleaned it up. Did close to 1200 miles in 2 weeks for work. Checked it again and it was barely wet. The revmax is a black unit so hard to tell if it's wet or not without running your finger or rag along the rear bottom edge of it. I never had to add any fluid and believe me I checked it often.

 

[KKBB]

If it has an o ring, I would have put some type of lube on the o ring. I also use some type of lube of flared fittings...granted that is in my profession in the water industry. On copper service lines that are flared, we use some type of lube to make sure it gets tight enough. Without it, it can feel very tight but will eventually develop a leak because it is just the copper and brass fittings together not getting tight enough...if lube is used it allows it to tighten down easier because of the lack of friction due to the lube being used.

 

[Bob Johnson]

Are you positive there are o rings for that side? I know they're on the circlip side. I can't remember since I did mine awhile ago. When I finally got around to fixing my seeping line I contacted Benny (oem parts guy) on here and he said it only shows them on the other side (circlip side). None on the back side of that thermal block with the threaded fittings. I'd assume both sides have o rings but again its been awhile. That's when I searched on here and saw someone else had to tape up the threads.

I was going to check and see if it actually had an oring but when I did that line the line itself stayed in there. So I left it kind of in fear if it was in there and partially damaged I would do more harm pulling the line back off.

If you think you lost a quart in 100 miles you have a leak. When I say mine was seeping I mean the bottom of the thermal block was barely wet and that was after a few thousand miles. Cleaned it up. Did close to 1200 miles in 2 weeks for work. Checked it again and it was barely wet. The revmax is a black unit so hard to tell if it's wet or not without running your finger or rag along the rear bottom edge of it. I never had to add any fluid and believe me I checked it often.

I'm pretty sure it had o-rings on both sides. I'm going to double check when I get home. I just drove it to the auto parts store (15 miles round trip) and bought a gallon of ATF+4. When I got back, the threads looked wet, but there was no fluid on the block and it didn't look like anything else under there was wet.

I've already go my stops planned for tomorrow. Going to stop every 30 miles and check the fluid level, top off if needed.

 

[2018power wagon]

I installed the PPE brand thermal bypass and a few months later was towing my camper about 160 miles one way and noticed trans fluid all down the side of New camper after getting to the campground, after letting it cool tightened all the connections and it was still leaking I thought from the threads, turns out the PPE thermal valve has a removable magnet on the very top that had loosened up and was leaking
Took a 10mm wrench to tighten and no more leaks. I dont know if yours has the magnet but you could check it was on the very top of the thermal valve.

 

[Bob Johnson]

*UPDATE*

Made it home OK. Stopped every 30 miles to check fluid level and not much leaked out. It wasn't as bad as the trip going to the campground. There was no ATF on the side of my truck but you could see where it was still dripping a little bit under the truck. The fluid level dropped maybe 1/16th of an inch on the dip stick for the entire return trip home.

I called ATS to see if they knew why it was leaking and to see if they had any suggestions. They said to put Teflon tape on the threads, which I have done. I have driven the truck about 30 miles and there is no more leak. If that changes I'll update the this thread again.

 

[BenchTest]

noticed trans fluid all down the side of New camper after getting to the campground,

That would make me ill. Very, very ill. I'm ill for you just reading it. I hate fluid leaks, but I REALLY hate fluid leaks that make a mess like that.

 

[BenchTest]

*UPDATE*

Made it home OK. Stopped every 30 miles to check fluid level and not much leaked out. It wasn't as bad as the trip going to the campground. There was no ATF on the side of my truck but you could see where it was still dripping a little bit under the truck. The fluid level dropped maybe 1/16th of an inch on the dip stick for the entire return trip home.

I called ATS to see if they knew why it was leaking and to see if they had any suggestions. They said to put Teflon tape on the threads, which I have done. I have driven the truck about 30 miles and there is no more leak. If that changes I'll update the this thread again.

Thanks for the follow up. Sounds like they "know" about their issue and that it's not uncommon. Seems poor to have flares and o-rings that leak and require thread sealer.

 

[JW2 Innovations]

*UPDATE*

Made it home OK. Stopped every 30 miles to check fluid level and not much leaked out. It wasn't as bad as the trip going to the campground. There was no ATF on the side of my truck but you could see where it was still dripping a little bit under the truck. The fluid level dropped maybe 1/16th of an inch on the dip stick for the entire return trip home.

I called ATS to see if they knew why it was leaking and to see if they had any suggestions. They said to put Teflon tape on the threads, which I have done. I have driven the truck about 30 miles and there is no more leak. If that changes I'll update the this thread again.

Good that it stopped leaking, but that stinks. Teflon tape? Yeah...it can go to higher temp than these transmissions run at, but to me that's kind of kludgy (no offense intended to OP) Especially for that price! I almost bought the same name brand, but after looking at how the o-rings seal went with cheaper one. Has never leaked since I put it in so far....hope I just didn't jinx myself!

 

[JW2 Innovations]

You could try next size up for O-ring on side leaking as a possible fix.....

 

[Hardracer]

Benchtest....you are being nice using the word "ill".
I think i would be using a few very differant words about it in phone call to the company.
The way others are saying..this should be a compression type fitting?is that right?and shouldn't need tape or a sealer.
And having to clean all that off to boot.