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knocking noise after lift installed

16K views 62 replies 16 participants last post by  jgalvar 
#1 ·
Installed a zone 4.25 combo on my 99 TJ and getting a knocking like sound when first starting off for about 2 seconds than goes away. It seems to be coming from the TC area. I added a few washer and dropped the TC about 1/4 inch and still the same noise. It does not do it in reverse or if I take off in 4wd. I get no other vibrations or noises when driving....I am not convinced it is drive train related, Any suggestions or remedies.

Thanks,

Dan
 
#35 ·
#39 · (Edited)
Sorry if that post sounded a little short, it wasn't met to be, but after I reread it, I can see where it could have been mistaken. I was trying to get you directed towards a previous post that explained the tc moving, without typing it all - I'm basically lazy:D.

There was one mention of someones front ds rubbing, but I really don't think you'll have a problem with that, at least not sitting at ride height. If I were you, I would remove the skid and check the condition of the transmission mount (actually tc mount) first. If it looks like there's any issue at all with it (if you have any question about the way it looks, take a pic of it and post it), replace it before installing any more new parts. If that fixes your issue, return the unused parts that you've already purchased.
 
#41 ·
Great thread guys. I have some nuisance knocking on take-off from my bone stock suspension 00 Sahara. I checked out the DS's in the past to make sure nothing was hitting/scraping anything else. I'm going to inspect the trans mount sometime soon to verify if it's the prob. Subscribed.
 
#44 ·
Great thread guys. I have some nuisance knocking on take-off from my bone stock suspension 00 Sahara. I checked out the DS's in the past to make sure nothing was hitting/scraping anything else. I'm going to inspect the trans mount sometime soon to verify if it's the prob. Subscribed.
Try pulling up on your 4wd shift lever and see if there's any resistance. If it doesn't feel like it's connected to anything, the linkage probably has come apart and is swinging and banging against the skid when you take off. This happened to me about a year ago, and I found that the reason the linkage kept coming apart was because the trans mount was broken and allowed the transfer case to move and pop the linkage apart.
 
#46 ·
This is a bold statement so don't bite my head off.

Any time you use a body lift on a tj you should install a Novak shift cable. The cheap *ss relocation brackets never seem to work right and if you install a motor mount lift it will definitely make the symptoms worse. The knocking sound is the mechanical shift linkage binding and groaning when the drivetrain moves around on the rubber motor/trans mounts.

You can follow the tsb and replace a couple of wear items on the shift linkage but they will just wear out again and the problem will be back.
 
#47 ·
Any time you use a body lift on a tj you should install a Novak shift cable. The cheap *ss relocation brackets never seem to work right and if you install a motor mount lift it will definitely make the symptoms worse. The knocking sound is the mechanical shift linkage binding and groaning when the drivetrain moves around on the rubber motor/trans mounts.

.
I agree, the Novak cable is a great upgrade and it's definitely on my list, but just not right at the top. It has to wait for the Currie stuff for the front end on mine. I'll probably put one in in conjunction with a tummy tuck that's also on the list.
 
#48 ·
No problems on mine with a 1" BL and 1" MML... We'll see if that holds after the new tranny skid goes on.
 
#50 ·
all right...outstanding job troubleshooters I think we have found the issue(s). I am going to play around with the TJ this weekend. A great excuse to drink some beer and turn wrenches. Last weekend home before a trip to Australia...hopefully I can convince the wife that this knocking noise is very important and it is a priority!!
 
#56 ·
Cleve....Thanks. I didn't know wether to buy both (the boot kit & the new mount) and try to get it from both angles or just try one at a time. My patience is getting pretty thin with this thing so I was trying to see if Dan (Ordie) got his fixed yet as well. Was that kit pretty self explanatory??? Come with instructions???
 
#59 ·
Returned home a few days ago(finally), just changed my Tranny Mount and no more knocking noise!!! I wonder if installing the MML does damage to the mount? maybe there should be a step to remove the 4 Screws that attaches it to the skid plate prior to lifting the motor.
 
#61 ·
That is one of the first steps! Was this not mentioned in the instructions? I did the Browndog mml recently, and this step was in bold, in several parts of the instructions.

Edit: I suppose I should check post dates...
 
#62 ·
Maybe, maybe not. When I replaced mine, I put the old and new side by side. There was no visible difference, but installing the new one made a huge difference. Tightened up quite a bit, no more banging, shifts from park to drive were smoother, take offs were smoother.
 
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