Knocking Sound after Lift in 4wd while Accelerating

[Elliott]

So I just got the TM Econolift installed last Thursday and am very pleased with it. I also re-geared to 4.10 at the same time. The roads were a little snowy here today so I engaged full time 4wd and I can hear a knocking sound under acceleration up to about 35mph. I don't know if the sound stops after that or I just cant hear it over the road noise. It doesn't make the sound in 2wd, only 4wd, and it is only when under acceleration...if I am off the gas the sound disappears. It seems to me to be coming from the drivers front but my wife who was in the back seat thought it was coming from the rear. Any ideas what it could be?

 

[tommudd]

First check the rear boot/CV on the front driveshaft
Then go to the CVs etc.
I'd bet the front driveshaft though right now

 

[CactusJacked]

Might be the driveshaft, but since front driveshaft angles don't change with a lift (didn't knock before), I wouldn't be surprised if it wasn't the shaft. I'd suspect the front axle cv's, and quite possibly the intermediate shaft (passenger side), since lifting accentuates the droop angle of the cv axles. But by all means, check everything.

 

[tommudd]

True but don't know how many times over the years after someone lifted then all of a sudden they had noises they never had before. Problem was they had them but never noticed
But yes CVs change angles and can if loose before now make noise

 

[tjkj2002]

Also check the front diff mounts since the front was out.To much droop in the front with to much lift can cause the CV's themselves to make a knocking noise from being past there max working angle.I ran into that once with a guy that had the JBA 6" lift.

 

[Elliott]

Thanks guys, I'll take a look later this evening weather permitting or tomorrow if not.

 

[Elliott]

Took a look under there this morning and it is the passenger side cv...grease was slung everywhere on that side lol. I am guessing that I should go ahead and replace the drivers side as well since it has the same amount of wear and tear. What about this intermediate shaft?

 

[Porkchop]

And seals? Almost standard now with me if doing the CVs, cheap insurance on the labor. Just saying! Also a good time to check that intermediate shaft.

 

[CactusJacked]

Mine was making the kind of noise you're describing on yours. When I got it apart, this is what my intermediate shaft looks like (pic shows new vs old one). The egged out end of the shaft was allowing the CV hub to flop around, which is what was making the clunking sound. Lifting the Jeep puts more downward pull on the cv axle, and if your shaft is bad, it can make what was not apparent at the time, now an issue.

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[KJScott]

might as well do left and right CVs, and intermediate shaft and use only Mopar axle seals. Then you are done with it.