First time here so thank you for having me. My problem is this, I have a 1988 Cheyenne and my 4X4 light does not work. I let my girlfriend drive it while we were muddin and she left it engaged and we started home.I should have checked but I was as usual buzzed. So long story short my front diff. started grinding and makin' all sorts of fuss.I found out that it was still engaged and took it out and put it in2 hi. So my question is this, do you think my front end is toast or can it still be good ? I haven't tried to 4 wheel since then for fear of gettin stuck and messin' something up worse than it already is.

 

The differential has probably overheated. You might can change the fluid in it and then give it a try. If that doesn't work, I don't know what to tell you other than to rebuild or replace.[/align]

 

I guess your differential needs some rebuilding now. Or worse you have to replace it with a new one.

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Chevrolet Tahoe Accessories

 

I did the same thing with my 1993 Suburban, and it caused no damage. I would be surprised if you need a complete differential rebuild/replacement. Provided that your differential was filled with the proper fluid to the correct level. As to the grinding, etc., if you run a 4WD vehicle on hard surfaces in 4WD, many times it will cause the transfer case to bind, and make it difficult to get out of 4WD. Back up 15-20 feet, and it will usually come right out. The light problem could be caused by failure of the junk actuator that Chevy used on the 4WD trucks of that era. Suggest you replace it with the vacuum setup by Warn (the winch people). You will get immediate engagement and more positive operation. You should also consider going full synthetic on all fluids, as synthetic will resist breakdown under heat.

 

I WOULD TEND TO AGREE WITH SAWFISH. IF THE FRONT DIFFERENTIAL WAS GRINDING THEN THAT WOULD BE METAL ON METAL, A GOOD WAY TO CHECK THIS IS TO DROP THE FLUID INTO A CLEAN PAN, AFTER FLUID IS IN PAN TAKE YOUR HAND AND STICK IN THE DIFF 3RD MEMBER AND SCOOP THE REST OF THE FLUID OUT (THERE IS USUALLY A SMALL POCKET IN THE CASE BY THE RING GEAR) AND RIGHT AFTER SCOOPING CHECK YOUR FINGER TIPS FOR METAL FLAKES IN THE LIGHT. IF YOU SEE SILVER FLUID AND LOTS OF SPARKLES YOU HAVE SOME ISSUES< REBUILD. IF YOUR FLUID IS BROWN OR BLACK WITH LITTLE SPARKLE THIS IS PROBABLY NORMAL. THIS IS WHY THE CLEAN PAN. AT THE BOTTOM OF THE CASE AND PAN IF YOU HAVE CHUNKS YOU HAVE ISSUES. IF YOUR NOT SURE WHAT TO THINK YOU CAN CONTACT A COMPANY IN YOUR AREA THAT CAN ANALYZE YOUR OIL SAMPLE AND TELL YOU THE PERCENTAGE OF EACH METAL OR PARTICLES IN YOUR OIL SAMPLE (HIGH PERCENTAGE=BAD) HOPE THIS HELPS.