Well after 150K thought I might take a look at the tranny fluid on my 95. Got the truck about a year ago and have done the long list, all the usual Blazer suspects. You folks no "The List". Had to yank hard on the tranny dipstick, rust all around the inside, fluid had the look, thickness and color of swamp muck! Tranny ran great! No leaks no hard shifts, of coures had to screw with it. Over two weeks did a twelve quart swap-out with a tube and drill pump, now nice and clear almost red. About a month later its starting to leak. To make a long question longer, should I put some sealer in there or maybe swap a couple of quarts of Valoline Max Life. Opinions?

 

More then likely that old fluid in there had some crud build up around the gasket and was keeping it from leaking, maybe some sealer will help seal the gasket that is leaking, but not sure. Its worth a try

 

If it's leaking from the pan, did you change out the gasket or siphon out the fluid from the dipstick tube? Either way, replace the gasket or make sure the new one is on and torqued right.

 

2x ^^ possibly the gasket got damaged also during removal or installation

 

Also look to see if the seal for the dip stick tube looks healthy. A hole can rust out in the tube too.

Go under and take a look for the source before you start to try anything.

Personally I can not think of a case where I would add sealer unless it was dying fast and it would be a few days before I could get a new one installed.

Changing out mucky ATF can lead to transmission failure if down all at once too.

 

Dipstick change and there was evidance of rust at top of dipstick. Does anyone know how the conection is made to tranny. Pipe nut and O ring? Compression? Best place to get a good eyball on it? Leak is from the front, found it doing ball-joints. Pan gasket dry. Un-touched on change. Thanks, Happy-Happy to all from Hamptobays.

 

Sounds like it may have been parked for a while and over time there was some water build up form similar to what can happen in unused/underused gas tanks/crank cases perhaps.

I would clean it off with steel wool or something like that really well and wipe some ATF from the tip up to the top and recheck it.

Not sure how it seals but in some it is rubber seal/o-ring. Often on leaks I have to do a lot of cleaning in order to find the true source.

 

Did you take the pan off and change the filter? Highly suggest that be done if what you say is true about the fluid being muck, then the filter has all that muck in it as well. But, If you did change it. Look around the pan for leaks. A lot of time when putting the pan back on people over torque the bolts causing the pan to leak. Plus when the pan is off make sure the holes in the pan are nice and even, this also can make a pan leak. I use a block of wood to make them flat again and torque to spec's.