Questions and Answers

Grinding Blazer

Q. 1998 Blazer - This has only happen 5 times since new however the dealer can not find the problem nor can they reproduce it. It seem to occur at 48 mph to 55 mph however it has happen at 60 mph. It sound like it is coming from the front end of the vehicle like the front axle is trying to engage.

It sound like two gears trying to engage at high speed but do not mesh together it is a low grind and then the pitch will continue to grind higher and higher until you slow down and at approximately 5 mph you hear a clunk and ever thing will return to normal.

Got a suggestion as to what the problem may be?

I am thanking you for any help you can give.
Mike

A. This would be a tough one to diagnose since it is extremely difficult to duplicate under controlled conditions. I guess the first thing I would suggest to do is check the tire circumference. In a 4WD vehicle it is very important that all four tires have the same circumference of the transfer case and differential will bind up, especially at higher speeds.

The next thing to look at would be the locking hubs. If they are manual hubs, then you need to make sure that they are locked or unlocked firmly. If you don't get a firm click in either position, they may float around between positions. If they are automatic, you could have the same condition, but you would not be able to check it.

If these check out okay, then the problem would be in the transfer case. In that case, opening the case and doing a visual inspection is the only way to determine where the problem is.