Auto Transmission leak only at highway speeds
 

I have searched and can't really find anything.
Have a 93 LT1 auto and the transmission leaks like crazy when I get it up to highway speeds, no leak putting around in a neighborhood say 35-40 mph. Big leak about 2 weeks ago, 2-3 quarts of ATF, wasn't sure so I was right by my vet shop. He put it on the rack and ran it in reverse for a hour and no leaks, took it home and drove it sparingly for a week and no leak. Took her on the highway as a test and big dump again. Added Trans-X and some supertech high mileage atf, a few days later another blowout at a speed test. Flushed radiator and cooling system last night since it got to about 220° during the test. Dropped the pan today, new filter, looked ok inside the pan, added 4 qrts of Dexron VI and Lubeguard red. took it for a spin, 183° water and oil temp while driving and once on the road at highway speed it blew out another quart.:ack:
So is my transmission toast, is the factory transmission cooler blocked or fracked ? Anyone experienced this ?
Going to the shop next week and he thinks the Transmission is getting hot due to the factory transmission oil cooler. I do not have a external transmission oil cooler installed yet.
Thanks

Got a go pro or access to one. Zoom in on the

Front main tranny seal area.
Rear main where the driveshaft is.
Pan gasket
O-ring for the dipstick tube.
Or a cracked/stripped tranny line going to the cooler.

If its leaking from anywhere else, the case is cracked. If the remaining fluid is still red and doesn't smell burnt and you can row threw the gears it should be good.Good luck

Not the pan or o-ring on dipstick, remaining oil is nice, not a line, cant see where the leak is.
It will be in the shop mid week

... There is a vent tube at the top center of the transmission , it favors the pass side ... If your trans is leaking from the vent , it could be overheat , over fill , or possibly internal problems ...

ok so first off you cant see any leaks but your losing fluid.. you sure its "leaking it" seems like just an assumtion, if it were leaking that badly that quick you would see it covering alonge the bottom of the car.
with that said i will bet on not a leak at all but using/burning it to be more probable.

i am not totally familier with the 93 lt vettes so which transmission is that because i cant remember if ther are any vacuum lines used on that transmission but im betting a situation similer to a vac modulator or such sucking your fluid into the engine, but maybe not.. just a possibility to check before blowing cash at dealer.

If you were losing a quart or two of tranny fluid on the freeway, your back bumper would be covered with poo.

:iagree: no doubt about it.

yes the bottom and rear is coated with fluid, cant see where the leak is coming from, it only leaks at speed though, no drips if i leave it in gear sitting even when its sitting for a long time or at slower speeds

is yours a late 93 with a 4l60 e or a early with a 700 r4

Put the car up on jackstands, clean off all the crud, run the car up to 40mph or so and watch to see where the leak is. You can't tell when everything is crudded up.

4160e
I have tried to eliminate the obvious and the flushes needed to be done.
Still trying to figure out how to check the internal transmission oil cooler without bypassing it with a external one

If you're talking about the oil cooler built into the bottom of the radiator, it that is leaking, you could have red coolant. Tranny leaks are actually pretty easy to figure out. Just run the car while you are watching underneath.

Only leaks once it gets up to speed

That could be a bit of a sticky wicket. Be sure to use some good 1/2" rope when you tie your wife/girlfriend under the car to watch for the leaks. :ack:

Didn't I see Bill Murray do that once?

Yeah that's the problem, I have a few people that I want to tie to the back.
Not much on the net about checking the factory cooler, I could always get a aftermarket cooler and bypass the factory one, will have to drop some cash and get it checked next week.
For the cost of a trip to m mechanic I could get a really nice big Trans cooler :leaving:
Butt I better bite the bullet and get it checked

Ugh so this is the Stock oil cooler ?
http://image.hotrod.com/f/techarticl...2bradiator.jpg

Since you have a 4L60E (they do have a temp sensor inside), is there a way to get the dashboard to display transmission temperature? My C6 will do that.

I think the only way you'll find the leak is to clean everything up and see where it's leaking. In my case it was pretty obvious (I had just removed and replaced the governor -- found this the next morning -- the governor cover was cracked):

http://www.misterpeachy.com/VettePic...ATF_Puddle.JPG

That is the stock oil cooler.

No gauge for the trans temp, only oil and water temp, no way I'm ramping it and being under it to find the leak.
Hope to have it in the shop this week.

if its a 4l60e the tcc isolater valve is known to wear and cause the converter to over heat and if the 3-4 clutches are worn the epc soleniod will bump pressure up to keep from slipping making the trans run hot trans will work ok till clutch plates finally burn up how many miles is on it ?