Banging noise when accelerating

MARK FRIZZELL

MEMBER
2001 MERCURY MOUNTAINEER
4.0L
V6
4WD
AUTOMATIC
150,000 MILES

All of a sudden I have this banging noise at acceleration. Does not seem like transmission is slipping, it feels more like transfer case chain when they slip.
So I got Vehicle up off the ground in drive, ( not running) and turned driveshaft feeling for resistance or anything different, everything seemed okay. So started vehicle put in drive and looked at everything, noticed all wheels turning except front left wheel was not upon acceleration it was trying to grab. Heard some noises so removed front differential cover found nothing out of norm teeth looked okay,
I know this was lengthy but tried to be as descriptive as possible,
I do not see anything loose but definitely something is slipping, CV does not look bad, should that front left wheel not be pulling like the other three?

3 Replies

ASEMASTER6371

MECHANIC
52,797 POSTS

Good morning.

No, you do not have a positraction in the front differential. Off the ground only one wheel will turn.

As far as the noise, I would first check the driveshaft universal joints to see if any are locked up. You will need to remove the shaft and move the joint manually.

Roy

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Thursday, March 8th, 2018 AT 7:00 AM

MARK FRIZZELL

MEMBER
141 POSTS

Would it be possible that a CV join that I visually cannot see is slipping under load?

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Thursday, March 8th, 2018 AT 7:24 AM

ASEMASTER6371

MECHANIC
52,797 POSTS

It will not be slipping it will be knocking from a burr in the race or the bearing. Very tough to see without removing the boots and visibly inspecting.

You can manipulate the joint up and down and around and if there is a burr, you will feel it. That is why I said to check the universals in the driveshaft.

Roy

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Thursday, March 8th, 2018 AT 8:11 AM