Differental question???

[vtdeucedriver]

Hey all, Ive been tweaking on the mutt and trying to get it run the best in can. Got her running pretty good and sounding like a Mutt!! During this time, a clunking noise has been driving me crazy. At 1st I figured that I got some dry rotted rubber bushings wore out. So yesterday I had a Soldier 2( my wife ) give me a hand while I lay next to the jeep and try and find where its comming from.

I found out that the drive shaft will make a 1/2 turn before the vehicle starts to move. If the clutch is let out too quick, I get a nice thunk. Guess I can assume that a differential change is in order????

[raymond]

Check your u-joints first. Especially the outer ones on the axles by the wheels. They have a reputation for going bad. The best way to keep that from happening is to keep them well greased. Do it more often than the L+O order specifies. I do mine twice a year, which for me translates to about every 500 miles. The best way to lube the outer u-joints on the axles is to get one of those miniature grease guns and put a needle on it. It makes it much easier to get to the zerks. Lot less mess and wasted grease too. I think the outer ones fail more often because it is harder to get to them with the grease gun.

[muttguru]

Raymond is most likely correct. It's usually the U-Js that go. There's an easy way to check....

1. Block the front wheels to stop the vehicle from rolling.
2. Put the parking brake on.
3. Jack up the driver's side rear wheel. Make sure the vehicle is safe on the jack.
4. Get someone to shine a torch on the wheel-driveshaft outer "U"-joint while watching the joint itself.
5. While that helper watches the joint, you vigorously turn the wheel back-and-forth.
6. If there's any play in that joint, he/she should see it.
7. Now do the same and watch the inboard "U"-joint.
8. Repeat this operation on the passenger's side rear wheel.
9. It may also be worth doing the same for the joints on the rear propshaft, too.

It could, of course, be the diff itself......in which case, swap the front and rear diffs. The front diff is usually in better condition....it has probably spent most of its life coasting along...unless someone has already swapped them before you got the vehicle....in which case, start searching for a replacement.

[vtdeucedriver]

So they are high pressure fittings???? I have not greased the jeep yet, infact if the weather holds, today I am going to do a oil change. The thunk is definatly the rear diff.


Who has the best prices???? I dont think I would even have a problem with a takeout at this point. I am stil saving $$$ for canvas seat covers

[muttguru]

The thunk is definatly the rear diff. Who has the best prices???? I dont think I would even have a problem with a takeout at this point.

Well, there's nothing like asking a question, getting two identical answers, ignoring the advice and going for the most expensive option (-:

[vtdeucedriver]

Hey ken, your post had not been up yet when I sent a reply............................I will do your check 1st before making any purchase.
Thats something I can do by myself.

[rickf]

Ken, I would like to propose an alternate method of cheching the joints that can be done by one person. Block front and back of the tire, couple of tires to be safe. Climb under and turn the drive shaft one way and then the other. You can use a strap wrench if you want to put a little more pressure on it. Doing it this way you can see all of The u-joints except the one on the transmission end, you can also see the amount of slop in the rear. You can do the front the same way while you are under there. To check the u-joint at the transmission end just jack up one wheel at each end, make sure wheels are chocked on other side, put transmission in first gear and twist the drive shaft again. This time you are putting pressure on the joint at the transmission, again, do the front while you are under there.
Rick

[vtdeucedriver]

thanks guys, I am learning alot from here. glad I joined.

[halftracknut]

If you have had the chance to drive it much and the rear end screams like a ______, well screams, put a take out rear in it and be done with it....Now I will catch the heat for that.....HTN....We can talk about rubber isolators later...

[muttguru]

Ken, I would like to propose an alternate method of cheching the joints that can be done by one person. Rick

Hiya Rick,

an excellent proposal. The reason I suggested a two-person troubleshoot was that Jeff had earlier got his wife to help him. Now that can only be a good thing.....the more she's involved, the less ear-ache for Jeff about "spending all his time with that %*@# jeep". (-:

[rickf]

Ken, I would like to propose an alternate method of cheching the joints that can be done by one person. Rick

Hiya Rick,

an excellent proposal. The reason I suggested a two-person troubleshoot was that Jeff had earlier got his wife to help him. Now that can only be a good thing.....the more she's involved, the less ear-ache for Jeff about "spending all his time with that %*@# jeep". (-:

[vtdeucedriver]

Well I am no spring chicken to this stuff. She has been with me for 3 deuces, 3 five tons and a 3/4. As far as the diff noise................it wont bother me. I am used to a turbo and not hearing the person next to me. I did not think the 151 whine was all that bad......................besides. I consider it "part of the mutt expirience"

[vtdeucedriver]

The thunk is definatly the rear diff. Who has the best prices???? I dont think I would even have a problem with a takeout at this point.

Well, there's nothing like asking a question, getting two identical answers, ignoring the advice and going for the most expensive option (-:

Going to suck it up and eat some crow but I am not sure if its the clunking that I am hearing. I still think the differential does not sound healthy but today I jacked it up as per Ken and rick. I DEFINATLY have a junk U joint at the right rear. I am going to try and push some grease in it to see if it makes it quiet. Then that might tell me if its the diff or not. But the U-joint will get replaced first and we will see!!!! Thanks guys!!

[raymond]

Jeff

You will be surprised how much noise a bad outboard axle u-joint can make. If you have a bad one, when you replace it, you will most likely start hearing all the other noises the M151 makes. Then you'll start replacing those parts trying to get the perfect quiet M151. Believe me, the only time an M151 is not making some sort of weird strange noises is when it is at a complete stop with the motor turned off. And even then, you can hear the unibody rust.

[rickf]

Don't even waste the grease, It will just make it that much messier to change the joint. You do NOT want that joint to let go. It will do lots of damage as it slings around under there. If a front one goes out it will take out the brake line, Ask Fil Bonica about how much fun it is stopping with no brakes and no drive shaft to slow you down! CHANGE THE JOINTS!!!!! The joint may not be the noise but it needs to be changed no matter what so just do it and then continue to look for the clunk. I have been chasing a bang that only happens on a certian type of turn and bump for over a year now. No it is not the shock.
Rick