now i'm stumped

[mr_mushroom]

i have an 85 c10 stepside that is puzzling me recently.
every now and then, it takes a shit.
sometimes when i get in to go to work, i put it in reverse. (to leave, you see)
as i pull away there's about a quarter cup of transmission fluid on the ground where i was parked.
now this is only on the initial start up in the morning, and very sporadically.
it doesn't do it when hot.
it doesn't do it even if i burn out and slam through gears.
i drove back and forth in one spot forever yesterday at work trying to MAKE it leak.
and this only happens about every couple of weeks, sometimes less. sometimes it'll be like 3 days in a row.
so i'm completely confounded.
i can't find the source because wherever it is, it's pressurized.
i find fluid on my driveshaft and on top of the h-pipe.
so very strange random fluid piles and i'm completely at a loss here.

just so the driveline info is here:
chevy 350+.10/700R4 (TCI 'street fighter')/shift kit/b&m quarterstick/3.73+posi
that's the only things i can think of directly affecting the tranny.

not that it leaks very much when it does, but it'd be nice to patch it up before it gets worse. iono maybe it just leaks. it's a chevy after all.

any ideas?

[2000CAYukon]

Might be worth putting the dye in the tranny fluid and using the UV light to find the source of the leak.

//2000CAYukon

[mr_mushroom]

hm.
not a bad idea.
thanks!

[MT-2500]

As said the dye and UV light will tell the story.
One place to check is the drive shaft yoke at the rear of transmission.
Some have a vent hole in center plug.
Another place for leak is the shift shat seal.
With a internal o ring seal on rear shaft.
If you park up hill watch around the rear tail shaft.

Clean off the old oil and drop some dye in it and craw under there and start watching for the leak.
MT

[mr_mushroom]

so i went and picked up some of that dye this morning and put it in.
no leak.
i've slammed on that tranny as hard as i can and it won't leak.
i guess i'll just wait until it happens again.

[MT-2500]

Originally Posted by mr_mushroom

so i went and picked up some of that dye this morning and put it in.
no leak.
i've slammed on that tranny as hard as i can and it won't leak.
i guess i'll just wait until it happens again.

10-4
Did you use the UV light and yellow glasses to check for the leak?
But You have got to catch it in the act or after it does it.
Make sure transmission is full good and hot.
Then park it on a level spot tonight and have a look under there in the morning.
Then if no leak on level ground park it up hill and recheck it.
Good luck MT

[mr_mushroom]

speedometer driven gear housing.

and only when parked uphill.

so i guess since it's not bad i'll wait until i get my new speedo and senders and cables since i was gonna do that anyway (speedometer isn't accurate, just like my last truck, lol) and just replace it all at once.

and i'll park downhill until then.
THANKS!

[MT-2500]

You are welcome and thanks for posting what it was.
Glad you found it.
That is half of the job done.
Did you use the dye and UV light to spot it?
MT

[mr_mushroom]

nope, dye's still in there, unused.
i parked it hardcore uphill and had someone start and shift into reverse while i was looking under it.