No Go. No Shift. No Gears.

[NBSTAHOE]

2007 4.8L Yukon: On the way home from work, I heard a “swshhhhhh” noise then lost all gears. 1-4 and Reverse. I checked the trans fluid level (warm engine, cycled gears, rested 10 min) still nothing. The truck doesn’t “feel” like it’s shifting into any gear. Just nothing. Topped off the fluid as it was low, it all leaked on to the ground. It seems like from the pan seal. Is my trans shot, or is there still hope until I can replace the 4L60e. Help please. Thanks. And happy Holidays.

 

[tom3]

When you say "rested 10 min" was that with the engine off? Should check with motor running, trans in park. That big leak could be a cooling line?

 

[NBSTAHOE]

When you say "rested 10 min" was that with the engine off? Should check with motor running, trans in park. That big leak could be a cooling line?

Yes. That was the engine off. It was raining and I couldn’t get up under it to really look. I checked with motor running and without. Running the level was at the cold mark. Off the level was the same.

 

[j91z28d1]

when you say it leaked it all on the ground?

like how much and how fast?

I asked cause years and years ago I had a tranny hose blow out on the highway. little blazer with 4l60 I believe they had well highway speeds but was a long 4 miles bridge, not wanting to be stuck in the side of the bridge we used to call the Frankenstein because of how many people had died in car accidents over the years on it. I kept going and limped it across. but the end it had pumped all the fluid out and had no gears. towed it home, fixed the hose and put in a gal or 2 of tranny fluid. all seemed OK. I drove it for a while longer and sold it.

if you lost all the fluid fast enough, and didn't run it long enough without fluid to eat up the pump. you might get lucky. I'd fix the leak, top it off running and try it.


after that, I don't know enough about automatics to guess. but a good scanner should be able to pull some codes and show you some live data from it. with that someone might be able to help.

 

[NBSTAHOE]

when you say it leaked it all on the ground?

like how much and how fast?

I asked cause years and years ago I had a tranny hose blow out on the highway. little blazer with 4l60 I believe they had well highway speeds but was a long 4 miles bridge, not wanting to be stuck in the side of the bridge we used to call the Frankenstein because of how many people had died in car accidents over the years on it. I kept going and limped it across. but the end it had pumped all the fluid out and had no gears. towed it home, fixed the hose and put in a gal or 2 of tranny fluid. all seemed OK. I drove it for a while longer and sold it.

if you lost all the fluid fast enough, and didn't run it long enough without fluid to eat up the pump. you might get lucky. I'd fix the leak, top it off running and try it.


after that, I don't know enough about automatics to guess. but a good scanner should be able to pull some codes and show you some live data from it. with that someone might be able to help.

It was a steady stream. Almost like when you forget to cut the faucet off all the way. It seemed to be leaking from the pan last night. But it could be that. I didn’t notice any issues. It does have 210,000 on the dash mostly highway miles. I poured a gallon of fluid in it last night. It all leaked out on the ground, steady, but not gushing.

 

[j91z28d1]

It was a steady stream. Almost like when you forget to cut the faucet off all the way. It seemed to be leaking from the pan last night. But it could be that. I didn’t notice any issues. It does have 210,000 on the dash mostly highway miles. I poured a gallon of fluid in it last night. It all leaked out on the ground, steady, but not gushing.

I would personally fix the leak and go from there. hard to troubleshoot it without the correct level of fluid in it. these autos work basically by hydraulic pressure to everything. without the correct internal line pressure from a lack of fluid. nothing works.

 

[Marky Dissod]

Engines can work without motor oil for quite some time, all things considered.
A transmission without ATF is USELESS. Get ATF back into it.
Better yet, soon after you get ATF back into it, drain it and refill it AGAIN, to clean out any issues.

Beyond that, can't hurt to analyze old ATF, would give you more data to go on.

 

[tom3]

I wonder if you hit a rock, knocked a hole in that pan? Or the seal/o-ring on the front pump let go. You'll have get under there and find it.

 

[NBSTAHOE]

So I got it towed this morning. Right before a thunderstorm hit. I did manage to get under it while it was hoisted up. It appears to be leaking from dip stick. Would a loose dipstick cause me to lose enough oil to make the trans not shift at all? I did have a hard shift between 1-2 didn’t see any trans fluid on the ground except once. Could this be the culprit? The dipstick?

 

[Marky Dissod]

Would a loose dipstick cause me to lose enough oil to make the trans not shift at all?
I did have a hard shift between 1-2 didn’t see any trans fluid on the ground, except once. Could this be the culprit? The dipstick?

... autos work basically by hydraulic pressure to everything. without the correct internal line pressure from a lack of fluid, nothing works.

Engines can work without motor oil for quite some time, all things considered.
A transmission without ATF is USELESS ...

I've seen engines run for DAYS without motor oil.
I've never seen an automatic transmission last ONE MINUTE without ATF.
Even the tiniest leak, given enough time, will drain enough ATF,
then your transmission turns your entire vehicle into an oversized noisy warm bollard.