Leaking CVT

gregory_tolson · Oct 23, 2019

Anyone ever have the female threads stripped that hold the CVT transmission pan? I had the dealer do a fluid drain and fill about a year and a half ago and have put about 30k miles on the car since then. Just a month ago I noticed some leaky transmission coming from the pan. I decided to tighten the bolts with a tiny 1/4 drive wrench and socket and noticed 3 bolts spinning freely and not tightening, low and behold, the threads were stripped. I had a shop put longer bolts in for me, RTV around the gasket and re-fill with new fluid. It was still leaking after that, they ended up dropping the pan again, extensively clean the mating surfaces, and re-RTV the gasket and bolt it back up. I'm gonna give it a few days to see if it leaks again.

Has anyone had this issue with the threads stripping? has anyone had the bolts drilled out and retapped with larger bolts? I wonder if the immense heat that the CVT can generate caused the aluminum threads to become really brittle over thousands of heat cycles.

Earthworm51 · Oct 23, 2019

Soft aluminum doesnt take much to over tighten. Can strip threads easy. So to speak.

Sandstone · Oct 23, 2019

Like EW said the metal is very soft and can strip easily. I haven't had one strip yet, but I've seen a couple of people here who have.

If it still leaks, you may need to check the pan to make sure it's not warped due to being over tightened.

If it's warped, the best thing may be to replace it with a new one, and get a good gasket, not one of those flimsy rubber ones.

The last one I put on was a Fel-Pro and it's leak free.

gregory_tolson · Oct 24, 2019

Sandstone said:
Like EW said the metal is very soft and can strip easily. I haven't had one strip yet, but I've seen a couple of people here who have.

If it still leaks, you may need to check the pan to make sure it's not warped due to being over tightened.

If it's warped, the best thing may be to replace it with a new one, and get a good gasket, not one of those flimsy rubber ones.

The last one I put on was a Fel-Pro and it's leak free.

Do you typically pour in 7.5 quarts of cvt fluid? Do you typically use mopar or a different brand? Ive realized the dipstick with the measurement feature just doesnt line up with the graph.

Sandstone · Oct 24, 2019

I don't remember exactly, but the last change was around 5-ish quarts give or take.

I don't use Mopar fluid. The first change I did was Valvoline, the second was Castrol Transmax.

Earthworm51 · Oct 24, 2019

gregory_tolson said:
Do you typically pour in 7.5 quarts of cvt fluid? Do you typically use mopar or a different brand? Ive realized the dipstick with the measurement feature just doesnt line up with the graph.

What temp was the fluid when you checked it ? The graph shows different measurements depending on transmission temp.

gregory_tolson · Oct 24, 2019

Earthworm51 said:
What temp was the fluid when you checked it ? The graph shows different measurements depending on transmission temp.

I would get the car up to operating temp, move the shifter into R,N,D,N, and R twice, pop the hood and check with the measurement dipstick. Kept getting like 70mm+. No where near the 36-44mm that graph B says it should be within around 200deg. F or so. How do you measure the temp? Do you stick a thermocouple in? Or measure the pan temp?

Earthworm51 · Oct 24, 2019

Thats one way or scan guage that tells trans temp. Scan gauge plugs into obd port under dash and can show engine temp trans temp voltage and others. You have to have accurate trans temp readings in order to match chart that comes with aftermarket dipstick. You are not getting correct readings from what you have been doing.

mr_et2 · Oct 25, 2019

gregory_tolson said:
How do you measure the temp? Do you stick a thermocouple in? Or measure the pan temp?

Besides scan guage, the Torque app will also tell trans temp, but a hand held laser thermometer to get pan temp will work too.

Steve53 · Oct 30, 2019

If there is enough wall around the stripped threaded holes, install stn. steel helicoils and maintain the same size bolts. Cheap and easy to do.

ajm113 · Nov 2, 2019

@mr_et2 Wait, does your Torque app actually read trans tempature? Mine cant, had to use OBD JScan... Bluetooth device perhaps?

mr_et2 · Nov 2, 2019

Yes, Torque on my phone does show trans temp. I have a bluetooth ELM327 reader. However, I also have Torque installed on my Android head unit, and that does not show trans temp. Maybe it's device dependant?

gregory_tolson · Nov 5, 2019

UPDATE So after going to a car shop they tried putting longer bolts in since the female thread leangth is longer than the bolts themselves. They also placed a bead of RTV all the way around the gasket and they re-filled the trans fluid but it kept leaking days after. I took it back and they extensively cleaned everything and re-filled again, it was still leaking.

I now have it at a transmission specialist shop and they are properly retapping the female threads and re-filling the tranny again

i'll update if the leak finally stops

Steve53 · Nov 5, 2019

Helicoils should have done it with very little time involved. Pan must have a slight warp if rtv didn't help with the seepage.

Sandstone · Nov 5, 2019

Steve53 said:
...Pan must have a slight warp if rtv didn't help with the seepage.

x2

Earthworm51 · Nov 5, 2019

All this time have filters been changed ? New trans pan with drain plug.

newbie77 · Apr 27, 2020

gregory_tolson said:
UPDATE So after going to a car shop they tried putting longer bolts in since the female thread leangth is longer than the bolts themselves. They also placed a bead of RTV all the way around the gasket and they re-filled the trans fluid but it kept leaking days after. I took it back and they extensively cleaned everything and re-filled again, it was still leaking.

I now have it at a transmission specialist shop and they are properly retapping the female threads and re-filling the tranny again i'll update if the leak finally stops

what happened?

Steve53 · Apr 29, 2020

gregory_tolson said:
Anyone ever have the female threads stripped that hold the CVT transmission pan? I had the dealer do a fluid drain and fill about a year and a half ago and have put about 30k miles on the car since then. Just a month ago I noticed some leaky transmission coming from the pan. I decided to tighten the bolts with a tiny 1/4 drive wrench and socket and noticed 3 bolts spinning freely and not tightening, low and behold, the threads were stripped. I had a shop put longer bolts in for me, RTV around the gasket and re-fill with new fluid. It was still leaking after that, they ended up dropping the pan again, extensively clean the mating surfaces, and re-RTV the gasket and bolt it back up. I'm gonna give it a few days to see if it leaks again.

Has anyone had this issue with the threads stripping? has anyone had the bolts drilled out and retapped with larger bolts? I wonder if the immense heat that the CVT can generate caused the aluminum threads to become really brittle over thousands of heat cycles.

If there is enough wall around the stripped holes, have them install helicoils (new thread inserts). You drill the stripped holes to the tap size of the outside threads of the helicoil. Then tap thread the holes and screw in the helicoils. The inside diameter of the helicoils are threaded to your original screw/bolt size. The end result is threaded holes that will use the same thread as the original bolts did. You can propably use the old bolts as long as the threads are good and not full of aluminum.

Leaking CVT

gregory_tolson

Earthworm51

Sandstone

gregory_tolson

Sandstone

Earthworm51

gregory_tolson

Earthworm51

mr_et2

Steve53

ajm113

mr_et2

gregory_tolson

Steve53

Sandstone

Earthworm51

newbie77

Steve53

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