Stuck in 4wd - tcase tranny fluid leak

[bigmike585]

I took my 88 suburban to new mexico elk hunting after thanksgiving. I ran the 4wd through the motions over the course of our 5 day hunt in the mtns and it did awesome. On our last day we left ruidoso and headed back to texas on our 5 hour drive.

When I got up on the highway i noticed a vibration/humming coming from underneath the middle front floorboard. It wasnt anything too loud so I cruised about 20 miles running about 75 mph and it never quit. So, I pulled over to investigate and found the front driveshaft was still turning, as I had suspected. I had taken it out of 4wd before we even got off of the last mountain trail. Somehow the tcase was still engaged and still turning the driveshaft but the hubs were not locked in because I did some tight turning in town and it hadnt acted like it was still in 4wd.

Anyhow, I shifted into 4low and then back into 2wd and the tcase disengaged, so all was good. But, some transmission fluid was leaking out of the tcase. I checked the fluid level and it never showed to be low. Then drove awhile and checked it again and it was fine and the transfer case wasnt leaking at all anymore. I suppose the vibration caused the tcase seal to leak.

I was wondering if anyone else has ever had this problem or if I should be concerned about the transfer case. All seems fine, it goes into 4wd fine now and everything works. No more fluid is leaking. I just hope I didnt take a bunch of life out of the transfer case.

Here's a link to more details of the suburban
http://coloradok5.com/forums/showthread.php?t=286316&highlight=brand+suburban

 

[Fordum]

Depending on what type hubs you have, its possible one of them might not have disengaged, but did after you shifted in and out.
Otherwise, your shifter linkage may be out of adjustment or the shift forks inside the transfer case may be worn.

 

[miniwally]

I took my 88 suburban to new mexico elk hunting after thanksgiving. I ran the 4wd through the motions over the course of our 5 day hunt in the mtns and it did awesome. On our last day we left ruidoso and headed back to texas on our 5 hour drive.

When I got up on the highway i noticed a vibration/humming coming from underneath the middle front floorboard. It wasnt anything too loud so I cruised about 20 miles running about 75 mph and it never quit. So, I pulled over to investigate and found the front driveshaft was still turning, as I had suspected. I had taken it out of 4wd before we even got off of the last mountain trail. Somehow the tcase was still engaged and still turning the driveshaft but the hubs were not locked in because I did some tight turning in town and it hadnt acted like it was still in 4wd.

Anyhow, I shifted into 4low and then back into 2wd and the tcase disengaged, so all was good. But, some transmission fluid was leaking out of the tcase. I checked the fluid level and it never showed to be low. Then drove awhile and checked it again and it was fine and the transfer case wasnt leaking at all anymore. I suppose the vibration caused the tcase seal to leak.

I was wondering if anyone else has ever had this problem or if I should be concerned about the transfer case. All seems fine, it goes into 4wd fine now and everything works. No more fluid is leaking. I just hope I didnt take a bunch of life out of the transfer case.

Here's a link to more details of the suburban
http://coloradok5.com/forums/showthread.php?t=286316&highlight=brand+suburban

The transfer case shifted out of 4wheel drive. It's a lever, so it's kind of hard for it not to shift out of 4wd. What REALLY happened is your hubs didn't unlock. That's why it didn't feel like it was in 4wd in town, it wasn't.

To unlock the auto hubs you actually need to stop, back up 50' or so and perhaps depending on temps and how much grease etc. the hubs have in them turn the tires and drive forward and backward a lot. They get a bit of a bind on them and need to have that bind removed to unlock.

Back in the day when the auto hubs were be-coming popular my mom used to blow them up all the time by not letting them get fully engaged in the winter time then letting the 6.2l diesel eat to get out of our driveway.

Dad installed manual hubs so that he could quit replacing auto hub parts.

Remember, Locking hubs only need a very thin, thin, thin layer of grease on them. Too much grease with the auto style and they engage slowly which leads to broken parts, and also a hub that doesn't dis-engage easy.

Nothing to worry about. The fluid in the Tcase probably got a little warm and expanded enough to push some out the breather no biggie. Check it and drive on.

 

[bigmike585]

thanks for the replies, im gonna make sure i back it up after im done with the 4wd from now on.

Like I said, no more fluid is leaking at all. Also, I know exactly what that humm coming from the floorboard is while driving at highway speeds from now on.