Well finally I get to share this with you guys. I towed a cargo trailer around 5000# over 700 miles, which included several mountain passes, four over 6000 ft.
We did this in two sessions. The first was about 190 miles. It towed great as I think I reported on here. The mileage was around 15 MPG. Well, the next leg came about three weeks later around 500 miles mostly up hill & four 6000 ft passes. Well,It seemed to tow fairly well in forth gear. With my Blazer in 3rd gear I would of had to run in the 3500 RPM range, so I opted to use Drive & try to keep it from going in & out of overdrive. Well things went well until I got around 80 miles from our new home. As I was going down a flat stretch of road, out of the blue I felt the RPMs start going up as I'm slowing in speed, Tranny slipping. Well I get into the town before our new home to find burnt tranny fluid covering the underside of the chassis. But it had stopped slipping. Well, fluid down about a 1/2 quart. So 55 miles to go I took off. About half way on another flat stretch it starts slipping again then stops slipping and drove into our new town. My wife was following me & she said it started throwing fluid, her cars front end was covered with burnt fluild. Well, I got the trailer to our new place & unhooked it & took it to a shop in town & left it because we had to return 500 miles to get out travel trailer. I called the shop the next day & told them to flush the tranny replace the filter & add a bottle of Lucas Stop Slip. I told them if it works great if not I pay the bill anyway. I kind of figured after adding new fluid it might just start slipping & need to be replaced. Well a week later I get our trailer to our new home & go to the shop to check & see what we had with the Blazer. The mechanic said it was really burnt, but the pan was not a basket of clutch material or broken parts. Well, this was 2 weeks ago we have driven the Blazer over 1000 miles since this & the tranny is shifting great. We are getting 21 MPG on the highway, 16-17 MPH in town. I can hardly believe this tranny still shifts as good as it does. These 4L60s are way tougher than I would of ever guessed.

Craig

 

yes they are.

as for what happened.
got a tranny cooler, if not add one.
you should have driven in 3rd gear and slowed down
you will have to replace that tranny sooner rather then later, glad it survived so far.
if your blwoing tranny fluid it could be because you overheated teh fluid and it puked out the vent hose, and if that is the case, heat is the number one reasons trannies fail.
or you have a gasket, seal that was weak and hte added strain caused it to leak fluid, replae the gasket/seal and keep an eye on it. watch your fluid level closely, especially under load. if it is a gasket/seal leak it will get progressively worse.

cnagrats on the move and glad to hear the truck worked well for you.


i once moved from washington state to illinois towing a 4x8 uhaul box trailer behind a dodge colt. the dodge colt is a little smaller then a cavalier. i went over three mountain passes in the winter, yep snow chains. i was passed by everyone on the way up and down the pass. and passed several others who where towing a trailer and laughing at us as they passed us. they were broke down on the side of the road and were long gone by time i got to them. anyway that tranny lasted another 3 years. take your time and dont push the equipment and it will do just fine, sure you may not be the fastest or even close to keeping up with the flow fo traffic. however none of them are going to pay your repair bills.

 

It's towing days are over, this is it for us. We have moved too many times in the last ten years. We bought a travel trailer & started traveling 10 years ago. My wife is a teacher so we kind of lived like that TV show "The Promised Land". She has found her dream job & I'm retired so we have found a small town we both really like close to family if I move again anytime soon it will be by myself I'm sure.
Yea, I figure I will have to rebuild it one day. To be honest I'm surprised it is even running now. I will most likely buy a reman GM unit when it goes. Heck with a 3 year/100,000 mile warranty a person can't go wrong. Your right I should of slowed down, but I needed to cover 500 miles in one day as it was it was 10 hours. As for a cooler that is on my list of "TO DO THINGS".

 

i recently towed a load of wood with my blazer. all told it probably wayed my blazer and a half, my front wheels left the ground on a couple of bumps.....ya bad idea she spat tranny fluid all over my exhaust...smeld good, but i threw some tranny honey in it and promised her i wouldn't do that ever agian

 

So far so good with my tranny. I was driving it the other day & I noticed it banging into second gear then it wouldn't go into overdrive. I stopped checked the fluid OK, shut it off went into store to get a drink came out started it up & it straightened out & has been good ever since. The way I figure it I'm on borrowed time with it. So every day it works I'm happy.

 

def. should have stayed in 3rd as hanr said, but glad she's still running strong. pretty lucky with that weight you pulled.