New strange Noise

[stonybrookpictures]

OK, 1979 Wagoneer, 401 Quadratrac. Occasionally when moving off the line from a red light, if i accelerate a little aggressively, I get three loud clunk's.
(Three because I quickly calm down the accelerator when I hear the noise).
I first thought it was my 6" lift springs shifting, it still may be. I now think it might be my 4WD system. Any ideas? I know I'm not offering a lot of info, I just thought maybe this is a common problem with a known solution. I have the correct fluid for transfer and quad boxes on stand by, I don't know what fluid is in them now. Perhaps that's the issue?

[devildog80]

Motor mounts?

Transmission mount?

Exhaust hangers?

Axle wrap?

Some things to check.

Mount a GoPro, if you have one, looking at each suspect item, then drive it and examine the footage.

[backroadin']

ujoints? Does it come from the front or back? Can u feel it in the wheel, the seat, the floor, or at all?
Jack it up and spin the wheels and the driveshafts back and forth, see if anything sounds or feels odd.
Quick clunks loke that lead me to think driveline first, but I cant hear them either.

[stonybrookpictures]

I'm thinking its the chain

I don't really feel it, just the sound. Probably its the chain. Just form reading other posts by people where it was the chain.
But I will check all of the above. Thank you.

[sierrablue]

Mine does a similar thing every once in a while, but I haven't heard it since it's been summer and the hubs have been unlocked, so I'm assuming mine is something in/on the way to the front end. But it only does it every once in a while, so I just don't understand it. It doesn't make it go any slower, it just makes a little noise taking off from stop signs sometimes. But I have a D20 so if you think it's the chain on yours then that's certainly not my problem (or if there IS a chain in the t-case I suppose it COULD be the problem )...let us know what you find.

[stonybrookpictures]

Chain tension

Checked the chain today with the screw driver method. I get 1.1/4 " - 1 1/2" play. I'm pretty sure that's not good.

[stonybrookpictures]

Fluid

Interestingly when I drained the unit I only got out 1 Qt. I believe it should have had 4 pints or 2 Qt. I"m on a slight incline with rear end down, so maybe its trapped a bit in the housing. Ill move to more level ground and check.

[stonybrookpictures]

Swap chain

So Chain can be changed while the unit is still in the vehicle correct?

[stonybrookpictures]

D 20

I don't think you have a chain. My problem seems fairly common. The previous owner rebuilt the transfer case but if they used poor quality chain apparently they only last about 10.000 miles.

Here is a god write up of rebuilding a D20
https://www.motortrend.com/how-to/18...na-20-at-home/

Mine does a similar thing every once in a while, but I haven't heard it since it's been summer and the hubs have been unlocked, so I'm assuming mine is something in/on the way to the front end. But it only does it every once in a while, so I just don't understand it. It doesn't make it go any slower, it just makes a little noise taking off from stop signs sometimes. But I have a D20 so if you think it's the chain on yours then that's certainly not my problem (or if there IS a chain in the t-case I suppose it COULD be the problem )...let us know what you find.

[babywag]

need to check QT chain and do not give it too much throttle until you do!
if a QT chain gets loose enough to slip it can grenade the aluminum case.

[sierrablue]

I don't think you have a chain. My problem seems fairly common. The previous owner rebuilt the transfer case but if they used poor quality chain apparently they only last about 10.000 miles.

Here is a god write up of rebuilding a D20
https://www.motortrend.com/how-to/18...na-20-at-home/

I know there's no chain in it, that's why I said that if there WERE a chain there, it was probably my problem. Bad joke sorry.

Thanks for the link though it'll come in handy! And good luck with your clunk.

['89_Wagon]

3 clunks.... huh. I get a grinding noise if I do the same thing but that's from bad engines mounts allowing the engine to twist too much.... allowing the front driveshaft to rub against something. That's on a NP229 setup though. Wondering how worn engine mounts might impact a quadratrac setup?

[rang-a-stang]

So Chain can be changed while the unit is still in the vehicle correct?

Yep! It's not hard, but plan a saturday for the first time.

is your still full time or was it converted to part time? It makes a minor difference. 1.24-1.5"?! YES! you need a new chain!!!

[stonybrookpictures]

Not driving until chain swap

Took a gamble and purchased a used Morse chain. I'll see how it goes.

[rang-a-stang]

Awesome! Let us know how it goes! Feel free to post some stonybrook project pictures too!