Heavy Trans Leak Under Load???A

I have a 93 SLT jimmy 4WD with I believe it to be the 4L60 (Not E)
tranny. I can drive it all over town and it will not leak and drives &
shifts fine but as soon as I get out on the highway and enconter a
grade and try to maintain 65-70 as an average speed I begin to leave
a smoke screen behind which I think I have narrowed down to leaking
out of the ring gear inspection cover, probably from the pump.
With 90,000 miles on it I am planning to have the tranny rebuilt anyways
but has this happened to anyone else?
Anybody have any suggestions for the cause of this?
Also is it typical that my front end feels squirrly in high crosswinds and
around semi trucks.
Ball joints and steering seem Tight and right.
Thanks in advance for any suggestions!!
"J"

It sounds like you trans might be getting hot. The best thing to try is change the fiilter and replace the oil to synthic flood(I cant spell very good)

Yes heat is definately an issue in Vegas 116f today but this has been on going since I got it in May (much cooller then and it has & not really ever overheated) I had oil leaks that I thought were the culprit but fixed all those.
I changed the fluid and filter a few month or so ago and it has made no difference, just getting worse. My trans guy said that there maybe something clogged in the pump and forcing it to release pressure at the seal but this is only by phone conversation, I have not taken it in yet.
Goes back to a thread I read about having the whole trans and cooling system sucked clean by professionals.
This one had never been done prior to my buying it. It only figures it would take a dump before 100K.
All I will say to all out there, if you have a newer or really low mileage truck with this trans change the fluid and filter regularly 10K to 15K and use drive not OD unless you are on the highway 55+.
My 92 v8 camaro outlasted everybodiies that I knew and had a record 145K on it when I sold it.
You do have a valid point 1993 jimmy!! I am also going to put an electric pusher fan for added cooling in this desert heat!!
Takeit easy and I hope it's cooler where you're at!!

What kind of fluid did you refill with, because I had a Ford minivan and it did the same thing and at the shop they told me that some trans should have synthitc fluid run in them because they get hot. That is all I run in all my cars now. By the way I no longer have the Ford.

Oh, it is a little cooler here in Missouri but not much it has been between 90 an 100

Yep that's warm enough for me!!
I will see if they recommend putting synth in the new trans when THEY install it, I just did my K5's tranny not to long ago and don't wanna screw with this one. (I do run synth in the K5) wasn't aware that it
made a temp difference.
Thanks for the tip! Oh and I put the Valvoline MaxLife fluid in the Jimmy.