Driveline feels like it is binding

1990 K1500 Pickup 5.7 4L60 125K Miles Original Owner

After a 10 miles freeway drive, I was stopped at a light. When the light turned green, it felt like something was binding in the driveline. I really don't know where or what. It was hard to tell but if felt like the rear end or transfer case. I could not pull over (no room) and it went away after 100 ft or so.

I nursed it home after work and jacked up the rear of the truck. Engine off, tranny in neutral and spinning the rear tires I could hear a noise coming from the Transfer Case. Almost a low sqweak. It was not grinding and the front end was not off the ground. I checked the fluid and the level was fine. Drained it and it did not look good. A dark red instead of light pink. Looking at my maintenace records, it looks like I did not change it for 40 or 45 K miles. I know that this is too long. I also dropped the tail housing and the snap ring looked fine so that is not the issue or problem. The U-joints are original and both of them felt fine while I had the drive shaft out.

Should I put use Auto Trak Fluid now or just replace it with the usual Dextron III?

Could the old fluid cause this?

I am still not sure that this is my issue or not. If anyone has any advice on how to trouble shoot or diagnose this, I sure would appreciate it.

//2000CAYukon

Well, I wouldn't use autotrak if it is not recommended stay with the Dex111. I once had a similar symptom in my 92 s-10 Blazer, it was the G 80 locking diff binding, but you can probably tell the difference, if you have he Eaton locker, pull the cover and take a look, they were troublesome. You may have to wait till it gets worse to really be sure.

Well, I wouldn't use autotrak if it is not recommended stay with the Dex111. I once had a similar symptom in my 92 s-10 Blazer, it was the G 80 locking diff binding, but you can probably tell the difference, if you have he Eaton locker, pull the cover and take a look, they were troublesome. You may have to wait till it gets worse to really be sure.

I do have the G80 option on my Z71 and I think that is a possibility. I plan to replace the fluid along with a new bottle of posi lube.

I should note that this problem actually happened twice. The first time it happened a worker was blowing leaves under my truck. I mean a lot of leaves. So when I pulled out of the parking space, I lost traction and noticed the binding. I pulled over and looked under the truck but did not notice anything. A few days later it happened coming off the freeway.

In your case, did you have to replace the locker?

//2000CAYukon

Forget the posi lube, not recommended for the Eaton locker. This is not a full time limited slip, just the regular stuff or synthethic will do. Your addt'l info definitely points to the diff.

Forget the posi lube, not recommended for the Eaton locker. This is not a full time limited slip, just the regular stuff or synthethic will do. Your addt'l info definitely points to the diff.

Thanks maxwedge, I was not sure if I needed the lube or not. My car also has a posi and it requries the lube (I think it has an Auburn locker).

I was going to review the manuals before doing anything.

Do you think a fluid change can help or is the locker probably shot? Is the Eaton rebuildable or do I have to replace it?

Thanks again maxwedge!

//2000CAYukon

You require the additive in ANY and ALL clutch type t-cases and differentials..
Also, it sounds to me like you have spit a planetary set or something in the back of the transmission.. I had a problem with the overruning clutch drum in a 700R4 a long time ago, did the exact same thing

Also, it sounds to me like you have spit a planetary set or something in the back of the transmission.. I had a problem with the overruning clutch drum in a 700R4 a long time ago, did the exact same thing

Well that does sound good. It is hard to tell where it is binding.

Is there anyway to know if it is the tranny without tearing it down?

Thanks,
2000CAYukon

It really is hard to isolate a problem like that.. I'd start by disconnecting driveshafts and spinning wheels... making sure gears aren't binding..I guess you basically did that already.. Have you tried turning the front driveshaft with it in 4wd with the engine off so the front diff is disengaged? I don't suppose its a chain or maybe the pump?

When mine blew up it took almost a year of driving for it blow completely and stop working..

When your driving down the road in overdrive and you downshift it to 2nd manually, does it coast or does it engine brake? Or does it chatter?

Have you tried turning the front driveshaft with it in 4wd with the engine off so the front diff is disengaged? I don't suppose its a chain or maybe the pump?


I did not try that. But will give that a try if the problem comes back.


When your driving down the road in overdrive and you downshift it to 2nd manually, does it coast or does it engine brake? Or does it chatter?

It shifted into 2nd and slowed down (engine brake). The binding has only happened twice. The only tranny issue I am having currently is when it downshifts from 2nd to 1st when the tranny is cold. Twice this has happened and when the downshift was suppose to happen it acted like it was in neutral. It does not happen when the tranny is warm.

2 years ago, it had a weak shift into 3rd or 4th. I decided to add billet servos and a larger boost valve (.471). That helped and I was going to pull the valve body at some point and maybe install a Transgo kit. Just never got the time. Maybe I will wait til it blows up.

I changed the fluid in both diffs and the transfer case on Saturday. I did find some metal shavings in the rear diff. 2 or 3 pieces that were maybe a 1/16 inch by 1/8 inch but not very thick. I could not see where they came from.

I have driven the truck and the problem (binding) has not reoccured yet. Guess I will drive it until it happens again.

//2000CAYukon

You require the additive in ANY and ALL clutch type t-cases and differentials..
Also, it sounds to me like you have spit a planetary set or something in the back of the transmission.. I had a problem with the overruning clutch drum in a 700R4 a long time ago, did the exact same thing
Read any GM manual on the Eaton G80 locker, no additive is required.

Read any GM manual on the Eaton G80 locker, no additive is required.
Talk about a freekin helet fire.....Is it not suppose to have the proper oil and I'll be damned if I can remember it right now.

75-90 diff oil or synthetic, the posi additive of old is not required with this type diff, it is not a limited slip/full time posi. Lets put this to sleep.

75-90 diff oil or synthetic, the posi additive of old is not required with this type diff, it is not a limited slip/full time posi. Lets put this to sleep.

I agree. I already filled both diffs with 80-90 gear oil since that is what my manuals call for.

I am more concerned that I found some metal shavings on the diff magnet. 2 or 3 pieces that were maybe a 1/16 inch by 1/8 inch but not very thick. I could not see where they came from.

Still waiting for it to happen again. I have owned this truck for 17 years and 125K miles. I will probably drive it into the ground.

//2000CAYukon

I'm checking out mitchell on demand to see what it says for you