Adding a stop leak to trans fluid

[harmony]

Is there any reason why I shouldn't add a transmission stop leak to my transmission?  Namely Blue Devil.  It seems to have the best reviews.  I have a very small leak. One of the heads of one of the "many" bolt heads on the back of my transmission is always wet (until I wipe it off), at the point of almost forming a drop.  Yes there is a stain on my garage floor right under it, so occasionally a drip will form but I've never seen it happen.  There are so many places on the back of the trans that it could be coming from.  I'm just not into pulling it all apart and replacing all the gaskets and or seals.  At least not at this time of year when the good driving weather is approaching.

 

But can the additive cause any harm?  I think it calls for just over an oz. to be added for my trans (fluid drive style) 

 

Yes I know, it's just leaving its mark.  But I've spent the winter stopping all the other leaks, so why stop at this one.

[DJK]

Most "mechanic in a can cures" I believe are designed to swell neoprene seals. Why not remove the bolt and apply thread sealer?

[harmony]

5 hours ago, DJK said:

Most "mechanic in a can cures" I believe are designed to swell neoprene seals. Why not remove the bolt and apply thread sealer?

I'm not quite sure if it's coming from that bolt.  It's the lowest one on the transmission.  The back of the trans is mostly sort of wet.  Barely enough to stain a piece of paper towel.  But it's still wet.  I know I'm being picky, but if I can stop it, why not.  I suppose I could take your advise and just do one bolt at a time until I cover them all.  If it still leaks then it's probably a gasket.  I did check to see if any were loose and they they were consistent with the torque setting.  

[Sniper]

I didn't realize there was a stop leak for manual transmissions? 

 

 

[harmony]

7 hours ago, Sniper said:

I didn't realize there was a stop leak for manual transmissions? 

 

 

Blue Devil Claims their product works in both.  Reviews say it does the job.  But I have never used it.

[kencombs]

1 hour ago, harmony said:

Blue Devil Claims their product works in both.  Reviews say it does the job.  But I have never used it.

If it is a seal leak, it may work.  Very, Very unlikely to help with gasket or bolt leaks.

[harmony]

45 minutes ago, kencombs said:

If it is a seal leak, it may work.  Very, Very unlikely to help with gasket or bolt leaks.

Yeah I'm sceptical as well since the chemicals in the product seem to be designed to swell seals 

[1949 p17]

oil dye doesn't lie. put a bottle of oil dye in anything leaking and run it a while and shine a black light or uv light on it. you might be very surprised where the leak is actually coming from. proper diagnosis is the most important tool. 

[Booger]

On 3/12/2022 at 1:27 PM, Sniper said:

I didn't realize there was a stop leak for manual transmissions? 

 

 

!st thing I thought of, Sniper...big 48 Windsor..gotta be an auto. If indeed its a 3sp manual those leaks you can track down and fix correctly. I would only use an addtive ass a last resort. Like using black pepper in a radiator for stop leak

[Dodgeb4ya]

Cannot hurt that trans...why not?

Try it.

[harmony]

I was just concerned that it might interfere with the hydraulic functions of the transmission.  However from any videos I've seen it seems quite thin.  So it should be compatible with my 10W oil I suppose

[Dodgeb4ya]

Make it a test so we can all learn good or bad if the magic stop leak works.

I have never seen a M-5 that doesn't leak a little.p