Leaky transmission pan & gear band nuts

[DILLARD000]

Sounds like a stubborn & irritating issue.
Think I'd try just putting RTV on both top+bottom of FelPro just in the area +\-6inches of the leak, not all the way around the flange.
If that doesn't stop the leak, next I'd try 2 FelPro gaskets stacked.
Several years ago, put RTV+FelPro on an engine oil pan, with leaky results, so I've not used RTV on pans since.

 

[Transman304]

The leak looks to to be above pan rail. There is a rubber square cut o ring and gasket that goes between bell housing and case. These get hard over time and began to leak.
Brad

Also have 2 o rings on the case connector that can leak in that area.


How much fluid are you loosing?

 

[Beetlejuice]

Would it be worth trying out some kind of Trans leak fluid first? Blue Devil?

quarter for scale - this is ~24 hours. not very deep here, just painting the foil tray

 

[Shran]

The only kind of Stop Leak I trust is a new gasket... that crap is a waste of time.

I have heard some of the head gasket stop leak stuff actually does work but that would make me nervous as hell, if I knew I had a bad head/head gasket and just some weird blue goo holding it together I wouldn't ever trust it. Who wants a car they can't depend on? Worse yet how many cars sitting in used car lots have had that crap dumped into the cooling system?

 

[wildbill23c]

You could try some RTV in the area where the leak is. Could be a casting issue with the pan or the transmission case, and the RTV would help fill in the discrepancy. As for using any sort of stop leak, NO!!!! It may stop or slow down the leak, but it'll also help stop fluid flow in places you don't want it to. Some very small passages in transmissions, don't want to be inducing anything into the transmission that could possibly plug up any passages, ports, etc.

Fel-Pro usually has great gaskets, but if you have an issue with a casing or a pan, it could very well still leak, the gaskets usually don't really take into account a gouge for example in a casting, or a dent in a oil pan, so its very safe bet to use an RTV sealer in an area to correct a leak like that. Have to of course make sure the transmission pan is clean of all fluids before using the RTV of course but its certainly a great idea...may not have to coat the whole pan, just the area its leaking from. Sometimes you'll see people using RTV in addition to gaskets to help hold them in place while they're installing the bolts to help keep the gasket from sliding around. Also, make sure your gasket is installed in the right direction, not sure on these if the gasket could accidently be turned around backwards, I know on a few transmissions the AOD I think is one where you can flip the gasket around backwards and it'll go on, but there's tiny port on the casing of the transmission that will get covered by the gasket if its backwards and you'll lose I think 4th gear if I recall....just saw it on a transmission video last week. It may not take much RTV to seal the leak so don't apply too much otherwise you could cause a leak further back on the pan.

 

[Transman304]

That leak definitely needs to be addressed. Transmission fluid will spread out more than engine oil so spot will appear larger with smaller amount of fluid. My opinion only is I wouldn’t recommend any type of additive and as far as RTV sealants not in applications that don’t require it. Your results may vary. Take close look at the band nut again. After looking at pictures again I would suspect the band nut just because of the clean area on the case where fluid has run down.
Brad

 

[Beetlejuice]

Feedback received, no "stop leak" will be used. I'm a bit stumped now.

I'll check on the band nuts, ill give them a bit of a twist to synch down tighter if I can. If the leak is above the pan and not a trans-pan/gasket issue I would 1, be surprised (it sure seems like an issue on the front side of pan, trending to driver side corner) and 2, I don't know what I can do about any other offending gaskets or seals.

I might have to bite the bullet and take the truck to someone who has a better chance at diagnosis and resolution

 

[Transman304]

The band nuts have a rubber seal to stop fluid from leaking between case and also seal threads.
Brad

 

[Beetlejuice]

these nuts are on order

Im guessing the trick is keeping the band adjuster still while the nut is backed out. same for when new nut is installed.

its going to be hilarious if the source of all that trans fluid around the lip of the pan is the leaky band & nut. it'll at least feel a bit relieved that the case and pan isn't warped.

 

[Beetlejuice]

OK so thanks to the feedback and inspiration from this thread ive quite possibly crossed the transpan/gasket off the list of culprits.

yesterday afternoon I went under and I stuffed a couple papertowels around the band nuts and ALSO the dip stick tube area. The paper towels definitely took up trans fluid and the lip of the pan was without drip.

while the band nuts clearly appear they need to be swapped, the primary offender of seep/fluid drip now looks to be the dip stick tube stem (or perhaps farther up, and dripping down?)...

I pulled the paper towel off the dip stick tube stalk/stem, mopped the area up a bit.. and lo and behold just a few moments later here's what I saw:

what the hell is that all about

 

[Beetlejuice]

some more info, I have not run/driven the truck for just over a week now. I only ran it last week after I changed the pan and gasket out again to cycle gears and fluid. I quite possibly have slightly under-filled the fluid as well. I think It could go another 1/4-1/2 quarts

 

[Beetlejuice]

And since I cant resist poking around this morning.. I checked the main tube itself for holes using an LED light shining down the dipstick opening, there does not seem to be any light leaks there.

the stem has a lot of slop though...

 

[DILLARD000]

Appears you've found your primary leak, around the DipTube.
Recall reading (somewhere in the forums?) that you can pull DipTube out & reseal that joint,
though I've never had need to do that.

PS:
Here's a thread with a part number for a new DipTube ORing

Trans Dipstick tube replacement - Ranger-Forums - The Ultimate Ford Ranger Resource

Drivetrain Tech - Trans Dipstick tube replacement - Is there anything that holds the dipstick tube in the transmission other than the bolt near the top of the pipe? Need to replace the tube since its rusted out near the engine.

www.ranger-forums.com

 

[Beetlejuice]

thanks for the link - it appears there are 3 parts in the assembly (not counting the dipstick itself).

The question is now, what else is needed to seal the inlet tube? The red material might be good enough, but perhaps ford advises to use some sealant.

1 - Filler Tube

2 - Filler Tube O-Ring

3 - Stem / Tube Fluid Inlet (plugs into transmission itself)

 

[Beetlejuice]

More poking around resulted in a new lesson learned, do not pull the Stem / Tube Fluid Inlet (silver with red sealant pictured above) without a fluid drain pan below. About 1/4 quart came gushing out and managed to push the inlet back in to stop...

I read somewhere that the fluid line was at approximately the pan-lip level... maybe thats only true when running? I thought id be able to pull the dipstick tube and Stem / Fluid Inlet and inspect/clean/possibly salvage.

its going to be really nice when this is all sorted out. fingers crossed my trans holds up to all the new fluids that have been cycled in.