Drivetrain Dumb Question: Transmission Fluid

90GTFIVO · May 1, 2014

If I put the wrong transmission fluid in my T5, could it cause the fluid to leak during?/after operation?

After installing a clutch and flywheel, I've had quite a bit of transmission fluid leak onto the ground. I have a pan under there now to catch the fluid. Best I can tell it's coming out around where the bellhousing and dust plate meet. It's a slow leak but creates quite a puddle after sitting for awhile. I think it'd be more likely for it to leak where the bellhousing bolts to the transmission though?

My mechanic told me it has to be dumb luck, he couldn't think of anything I could have done wrong to cause this issue. I think I put the DEX III fluid in instead of MerconV.

NOTE: This is on my 93GT, in case you were looking at my sig, which is for my 90

madspeed · May 1, 2014

Theres no fluid running in those areas so thats not it. Is the shifter mounted properly?

jAEded · May 1, 2014

Is it oil, or trans fluid?

There is a input shaft seal on the front of the T-5, behind the throwout bearing guide. Also, could be your rear main seal if its engine oil.

I've seen old original engine seals go out when changing over to synthetic oils.

For it to leak when your car is off and static leads me to believe its a seal that is beneath the oil level, which ever oil it may be. However, I could be wrong and it could be pooling up during operation then leaking to the ground when static?

I have also seen the oil pan gasket leak where it wraps under the rear main. Mine did.

90GTFIVO · May 1, 2014

madspeed said:
Theres no fluid running in those areas so thats not it. Is the shifter mounted properly?

Best to my knowledge. I had a little trouble getting to the 4 bolts, but I managed. Are you worried about it being loose? If not, what were you referring to? It seems to operate fine when driving.

90GTFIVO · May 1, 2014

jAEded said:
Is it oil, or trans fluid?

There is a input shaft seal on the front of the T-5, behind the throwout bearing guide. Also, could be your rear main seal if its engine oil.

I've seen old original engine seals go out when changing over to synthetic oils.

For it to leak when your car is off and static leads me to believe its a seal that is beneath the oil level, which ever oil it may be. However, I could be wrong and it could be pooling up during operation then leaking to the ground when static?

I have also seen the oil pan gasket leak where it wraps under the rear main. Mine did.

It's definitely trans fluid. I think you may be right though regarding it pooling up during operation and leaking while static.

MFE92 · May 1, 2014

There's nothing about those fluids that would cause a leak by themselves. It's also not a very common place for a leak.

jAEded · May 1, 2014

MFE92 said:
There's nothing about those fluids that would cause a leak by themselves. It's also not a very common place for a leak.

^ +1

Also, you used the correct fluid. I like Royal Purple... For the leak, could be random, or something else happened. If it was the shifter I wouldn't think it would make it to the bell housing... I had to replace my throw-out bearing when I first bought the car and I did the front seal for the gearbox at the same time. Helps to operate that way.

Gearbanger 101 · May 1, 2014

Any chance you overfilled it? It's not uncommon to leak out of the seal on the tail shaft, or the vent on the side if they've been overfilled.

What really awesome is when you overfill it, then take your car for a drive. Get into a little brisk acceleration and watch the cloud of smoke as it pours out the vent and onto your hot exhaust.

I damn near pooped when I looked in the rear view and saw that one. The car spitting a huge cloud of smoke into the air behind me....thought I ruined my brand new 331 within the first 20-minutes of driving.

90GTFIVO · May 1, 2014

I definitely could have overfilled it. I'm going to drain and refill tomorrow after work. Is MerconV ATF the correct fluid for a T5? One person mentioned I used correct fluid when I used DEXIII ATF. Also going to call local parts department to get correct fluid level.

Can anyone tell me a little bit more about how the shifter could cause a problem? I'm not totally following that one. The shifter plate that bolts to the top of the transmission (4 bolts) is a little loose. I can see it move a little when I push on it. I must not have the bolts torqued down tight enough. Would this cause an issue?

madspeed · May 1, 2014

My thought on the shifter was that you filled the fluid from up there, most likely way overfilling it, causing your issues.

madspeed · May 1, 2014

Easiest way is to fill from the shifter, but by removing the fill plug below to prevent overfilling. When it leaks out the fill hole, its full

90GTFIVO · May 1, 2014

Thanks madspeed.

I filled using a siphon hose/pump, but I did add a little extra through the shifter box. There's definitely a chance I overfilled. Like I said, I'll drain and try it again tomorrow night. Hopefully I luck into overfilling being the problem.

madspeed · May 1, 2014

Most likely, no harm though

90GTFIVO · May 1, 2014

Even knowing it sounds like there should be no fluid in these areas, I'm going to go back and check/torque bolts where bellhousing bolts to trans and also where bellhousing bolts to dust plate/engine

Gearbanger 101 · May 1, 2014

Don't bother changing your trans fluid. Dexron III is just fine in these things. Frankly, they'll run on pretty much any ATF trans fluid. Don't sweat it. Just drain out the appropriate amount and enjoy your car.

jAEded · May 2, 2014

90GTFIVO said:
Is MerconV ATF the correct fluid for a T5? One person mentioned I used correct fluid when I used DEXIII ATF.

The book calls for synthetic Mercon E6AZ-19582-B or equivalent, 2.6 litres or 5.6 pints. Gearbanger is right.

I use Royal Purple Syncromax with good results. I put about 250 miles a week on my car. It is more critical that you use ATF fluid over something like gear oil.

jAEded · May 2, 2014

I guess its been replaced by Motorcraft XT-2-QSM. Good luck finding it.

90GTFIVO · May 2, 2014

Thanks for all the help!

v8only · May 7, 2014

dextron mercon atf...and synth atf is just wasting cash.

pull the top fill plug, pull the shifter, fill through the shifter hole till it leaks out the top fill plug.

tightening the bell to trans or bell to block bolts will do absolutely nothing. If it's leaking out at the bell housing, and it's not overfilled, you have one of two problems.

1. The seal inside the bearing retainer is shot

2. the silicone between the bearing retainer and trans is bad, and leaking there.

Either way, if you can't stop the leak, it'll sling oil all over your new clutch and destroy it..don't drive it till the issue is fixed

89oem · May 8, 2014

youll see where it came out the overflowed ...leaves a trail where dust and stuff sticks to it...

Drivetrain Dumb Question: Transmission Fluid

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