241C Transfer Case Binding

[90GMCZ71]

1990 GMC Sierra K1500 5.7 4L60 125K Miles Original Owner

 

Today after getting off the freeway (about 10 miles), the driveline felt like it was binding when a light turned green. It went away after 100 feet. It was hard to tell what was binding (and where). I nursed it home after work.

 

After gettting home, I jacked up the truck and tried to find where it was coming from. Spinning the rear wheels with the tranny in neutral, I could hear a noise coming from the New Process 241C Transfer case. Almost like it was whinning or a dull sqweak.

 

Checked the fluid level and it was fine. Drained it and the fluid needs to be replaced. I guess I missed this at the last major service about 20K miles ago reach means it could have been in there for 45 - 50K (I know that is too long).

 

I also pulled off the tail housing to inspect the C clip since I know that can be an issue. It was fine and I put it all back together.

 

Tomorrow I plan to refill with either Tranny Fluid or Auto Trak Fluid (looking for a recommendation, I read conflicting posts about older Transfer Cases using the Blue stuff).

 

Is it possible that old fluid could cause this? Any advice you can give me? If new fluid does not resolve the issue, I may be toast.

 

Thanks,

90GMCZ71

[GM-Tech]

Is it possible that old fluid could cause this? Any advice you can give me? If new fluid does not resolve the issue, I may be toast.

 

I don't see the fluid causing this, as long as it was full, which you said it was. I don't recall what type of fluid that one takes. Look in your owner's manual if you have one.

[90GMCZ71]

Is it possible that old fluid could cause this? Any advice you can give me? If new fluid does not resolve the issue, I may be toast.

 

I don't see the fluid causing this, as long as it was full, which you said it was. I don't recall what type of fluid that one takes. Look in your owner's manual if you have one.

 

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I have all of the manuals for this truck and it calls for Tranny Fluid.

 

The truck also has the G80 (limited slip) option. I can't really tell if the binding was the rear or transfer case. I plan to pull the diff cover this weekend and take a look. After that, fresh fluid and posi lube and we will go from there.

 

Thanks,

90GMCZ71

[KB06YUKONXL]

Sounds like the Tcase. If there is a clutch in that case that could be it sticking. I always change the dexron out of my tcases for Mobil1 synthetic ATF right after break-in because then I can leave it in there longer and it won't break down. Try some new ATF and see what happens. That should be a dexII application so dex III should be fine.

Just make sure you use the right diff fluid with the correct friction modifiers for the limited slip.

Try cycling the tcase in and out of 4WD to see if it is sticking or engaging when it shouldn't