Need Advice!!! Clunk, Clunk sound when accelerating AWD 97 Merc Mtnr

[tahoe_photog]

I've read several forums and am still unsure of the source of the sound. It started with a single loud "CLUNCK" sound while accelerating from a stop sign on a slight hill. Even though I've been babying it, the problem has gradually gotten worse and creates multiple "clunk, clunk, clunk" sounds when accelerating even slightly or when traveling up a small hill. It does it in all gears including reverse. It will also do it while stopped and hitting the gas and brake pedals at the same time. When I'm traveling on a highway it seems to stay away unless I accelerate hard. I'm trying to baby it for now so I can drive the 200 miles back home go to work to try to pay for a repair. When traveling up a hill now, it appears I loose a little acceleration with each "clunk". The trani fluid seems normal. Their hasn't been any leaking. It's getting worse fast even when I just drive on the flats at a steady speed. Now I'm questioning whether I can make it back home over the hills or not. It's not a "click, click, click" sound, so I doubt it's cv joints. Sounds like I should be praying it's not the transfer case!

Specs:
1997 Mercury Mountaineer AWD, 5.0L, owned from 114k-137k miles.

Possibilities so far:
-front drive shaft
-rear drive shaft
-transfer case

My questions:
What might it be or not be?
What cost am I looking at for a garage to repair it?
Do you belive this could be something an average DIY person (framer not a mechanic) can repair?
What tests could I perform to diagnos the issue?
How can I tell if it's the front or rear drive shaft?

Any advice will be greatly appreciated!

-Randy

 

[Turdle]

You are on the right track-go here

http://www.explorerforum.com/forums/showthread.php?t=227481

 

[williams.cory]

Thats is EXACLY what mine was doing! EXACLY. I was worried for a while because I thought it was my transfer case. But I just took the front driveshaft off today and that was the problem. Mine started off as just 1 clunk and its gotton so bad now, that if I try to accelerate more than normal that it will do lots of clunking. It even would clunk a lot going 55 M.P.H.. Take your front driveshaft off to see if that is the problem.

 

[williams.cory]

As to answer your other questions: Yes, this is a DIY project. Just need to take 6 8MM blots off at the t-case and 4 T-30 screws on the front diff. Its really easy. I had get a hammer and tap it a couple times to break it free. A new d/s cost like $230.00. But I am sure you can find a good used one for far less than that.

 

[tahoe_photog]

Thats is EXACLY what mine was doing! EXACLY. ...Take your front driveshaft off to see if that is the problem.

Oh that's good news guys! Especially since I only have a small socket set with me and the rest of my tools (not much more) are 200 miles away. I'll take a look at it as soon as it stops raining.

Is there any way to determine if the problem is in the front or rear driveshaft?

 

[williams.cory]

It wont be the rear driveshaft because all it has are u-joints. THe front driveshaft has a CV joint at the end connecting to the transfer case. The CV Joint is what is giving you the problem. Just make sure that you have quality tools while trying to break free the bolts. All you need is a 8MM socket and a medium to long extension to rech the bolts. And for the screws that go to the front differentail, all you need is a T-30 bit. And it will help if you can jack it up a couple inches in front. I'm sure you you dont have the right bit than you could run down to the autoparts store and buy one?

 

[tahoe_photog]

...Just need to take 6 8MM blots off at the t-case and 4 T-30 screws on the front diff. Its really easy...

A T-30 bit! I new I should have brought more tools with me!

 

[williams.cory]

To take off the T-30 screws on mine was really hard! I sprayed some penatrating oil on it and it was still hard. All I had was a screw driver with the T-30 bit in it and I could not turn the screws. So I had to get some medium sized pliers and clamp them onto the screw driver so I could break them free easier.

 

[tahoe_photog]

THe front driveshaft has a CV joint at the end connecting to the transfer case. The CV Joint is what is giving you the problem...

I'm confused...
If this ends up being the issue, do I replace the CV Joint or the Front D/S? Do you believe it's okay to drive it to the auto supply store with the Front D/S removed? There are hills coming back. Also, how long did this take you to replace?

Thank you so much for your time Cory, JTSmith and everyone else that posted in your thread!

 

[tahoe_photog]

All I had was a screw driver with the T-30 bit in it and I could not turn the screws. So I had to get some medium sized pliers and clamp them onto the screw driver so I could break them free easier.

Good advice! I might have my vise grips; and I'll pick up some WD-40 too.

 

[williams.cory]

The CV joint cannot be replaced. You have to buy a whole new d/s. As to driving without the front d/s I dont know, I posted a thread myself asking for input. I drove mine around a little bit with no problems. I suppose if you absolutely have to drive without it than its ok. Some people say that they have drove months without it and others say it is really bad for the vicous coupling. The d/s just went bad in mine. I just took the d/s out like 3 hours ago on mine......

 

[tahoe_photog]

The CV joint cannot be replaced. You have to buy a whole new d/s. As to driving without the front d/s I dont know, I posted a thread myself asking for input. I drove mine around a little bit with no problems. I suppose if you absolutely have to drive without it than its ok. Some people say that they have drove months without it and others say it is really bad for the vicous coupling. The d/s just went bad in mine. I just took the d/s out like 3 hours ago on mine......

You rock! Thanks so much! I have to get ready for Halloween now. I'll look at it tomorrow morning and will post my findings. Good luck!

 

[williams.cory]

Glad to help. Good luck on yours too.

 

[Beadmn]

Ive been driving mine about one month without a front shaft.I am not a mechanic but cant understand how it could hurt the transfer case or viscous coupling,