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Grind while decelerating

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15K views 23 replies 14 participants last post by  aaronlam  
#1 ·
So I have the Rovertym 2" lift (it`s more like 2.5" though) and Rovertym trailing arms. There was a grind while decelerating, everyone said it was the driveshaft. So I replaced the driveshaft with a Tom Woods double cardin shaft. It still grinds. So I adjusted the trailing arms, and went from a 3/8" spacer down to a 1/8" spacer. Still grinds, but slightly less.

The low pitched grind only occurs while decelerating at speeds above 30 mph or so. Otherwise, while accelerating or holding a steady speed, it runs just fine. In fact, it runs beautifully, which leads me to believe the differential and transfer case are doing just fine (I would think if there were issue with either of those two, the problem would be more constant, not just while decelerating?).

I don`t particularly mind the grind, because the truck is running very well, and you don`t really feel it, it`s just that it sounds awful. Any input or ideas though? I just want to make sure this is normal, because i`m in the process of selling this truck, and I don`t want to pawn off a headache on somebody else (like the previous owner did for me in so many regards).

-Nathaniel
 
#3 ·
it doesn`t sound like it is comming from the transfer case at all. It seems like the sound is too far back. Also, I don`t have any insulation over the t-case, so I can hear it and the transmission quite clearly.

Follow-up Post:

I neglected to ask though- worst case scenario, should it come to my looking into what you just suggested, could what you suggested be addressed by removing the tranny tunnel and center console, or does it require dropping out the t-case?
 
#4 · (Edited)
I thought it might be worth checking out as I did alot of what you did before hand. The main thing that sounded familer was that it happend under back pressure.

As to what is required, took 20 min. to discover. Drained the t-case fluid, saw some grindings, pulled the round cluster cover and bearings hit me in the head, never had to pull anything else. Good luck.
 
#6 · (Edited)
oldscratchggf said:
So I have the Rovertym 2" lift (it`s more like 2.5" though) and Rovertym trailing arms. There was a grind while decelerating...
Last month I too installed a 2" Rovertym lift and now experience a "grinding" type sound when I decelerate - when I press the accelerator the noise stops - for me, I don't hear the noise at speeds under 50mph - but that could be because the musics on too loud :)

If you find a solution or if it's nothing to worry about please let me know too...
Thanks!
Paul
 
#8 ·
pmd said:
If you find a solution or if it's nothing to worry about please let me know too...
Thanks!
Paul
Well, my truck has been doing it for at least the past 20,000 miles, and it still runs just fine. At this point, due to the fact that it has gone 20,000 miles without getting any worse any without having anything fail, I would think it`s nothing to worry about. Still sounds awful though.


jimmy salmon said:
i had the same thing when i decelerated, thought it was the t/c. turned out to be the rear diff on the way out
I would think that if it were in fact the differential on it`s way out, the symptoms would be more standard through accelerating, coasting and decelerating. That, and I changed the oil in the diffs, and there was no sign of carnage.

Any further ideas or input would be greatly appreciated.
 
#9 ·
I know I'm raising something form the dead here but I'm haveing the same problem and not sure I found an answer in this thread. Couple of weeks ago I put a TerraFirma lift in. Now when I let off the skinny pedal I sometimes will hear and feel a growling and vibration. It is almost like the pavement has been grooved.

I picked up one wheel at a time and spun each one. I couldn't get any of them to make any noise or grinding. I have oil in the diffs. Changed the oil in the transfer case. Still the same.

It just doesn't seem right. Any thoughts?
 
#11 ·
Common denominator is that you all are lifting your trucks!!! I bet it has something to do with the only thing that really changed, the driveshaft!! Put the truck on four jack stands pull the tires and put the truck in first gear low and get under your truck with a flash light. I bet the noise is coming from where your rear driveshaft mounts to your output shaft. Just a guess, I've been wrong before a lot. I did this and my noise is coming from the rear shaft:) I just carry spare u joints. Just happy it wasn't the freshly rebuilt rear end!!
 
#13 ·
Keep shimming the rear links, I dealt with this years ago. I have Rovertracks rear links (RIP) and I believe I added and 1" or so of shims and it went away. Same thing happened with my Range Rover I shimmed and did all sorts of tricks. It ended up being the front driveshaft, even after new u joint and being balanced I still had the noise/vibration. I replaced the front with a used one from Paul Grant and it solved all my issues.
 
#14 ·
X2. 2 inch + lifts can require adjustable trailing arms, DC shaft in the front and maybe an extension of the A arm bushing.

Some say a rear DC is not necessary.

I find the vibes are more noticeable and never truly went completely away in my 97D whereas the same set up in a 94 I had years ago never blinked. I'm running 411's in this 97 so the extra RPMs isn't helping either.

Clay
 
#15 ·
Forgot to mention that when I had it lifted up and was spinning the wheels I noticed that I could grab the rear Drive shaft and that when I changed directions it would kind of bounce when it met resistance from the other direction.

TWO DUMB QUESTIONS
One, what is DC Shaft? You mean the Drive shaft. Never heard DC before
Two, shimming rear links not sure I know what you are talking about or where to get or must I make shims.

Thanks
 
#16 ·
DC refers to a double cardon, which is basically two uv joints side by side.... I believe they are also referred to as a cv?

You shim your rear links where they hook up to your frame bushings.. It has the effect of tilting the diff and changing the pinion angle....
 
#18 ·
I picked up a Tom Woods DC Shaft from the classifieds here (http://www.defendersource.com/forum/showthread.php?t=50360) for my 1997 D90 with Terrafirma 2" lifts. I also had the grinding noise above 50mph and only during deceleration. I finally got around to installing the DC shaft. The DC shaft has 2 spacers/adapters to fit the rover diff flanges. Its seems too thick because when the DC shaft rotates, the one attached to the diff flange is rubbing against the catalytic converter; only the edges of the universal joints are hitting the catalytic converter.

Question: Can I have machine shop reduce the thickness of the aluminum adapters to clear the catalytic converter? Will the shaft still be balanced and long enough?
 
#20 ·
Just read through this old thread. Like others said.. It is your rear drive shaft angle. 99% of the time you do not want to shorten the rear trailing arms! you want to add length with shims.
If you set it up right you don't need a dc drive shaft. I run a stock rear drive shaft with 3" springs and runs perfectly.

Put truck on a level surface.. Garage floor
Pick up a cheap magnetic angle finder and put it against the bottom of the brake drum and record the downward angle.. It's usually about 1 or 2 deg
Now put it on the flat parallel spot on the 3rd member to get your pinion angle. It will prob be over 5 or 6deg

The goal is to have it match the t case angle so to if you ad a shim or spacer to the rear link, it will decrease the angle of the pinion angle giving you no vibs

Remember these instructions are for running a standard drive shaft not a dc version.

Also I prefer roverTym rear links. They come with 3 sets of shims to dial in your pinion angle perfectly and are much stronger than stock with a nice ramp build into them.

I will try to snap a pic or 2 later as I can dig my garage door out of snow to get my truck out finally.

Randy
 
#21 ·
Randy any chance of getting photos. I would like to see. Time is clearly getting away from me but I haven't fixed this problem and would love to see your photos. Think I got it but.....picture is worth a thousand words.


Thanks
 
#24 ·
No affiliation but saw this today.

http://www.ir4x4.com

Product Developed by IR4x4:
Due to the need for correcting the pinion on all lifted Land Rover vehicles, IR4x4 developed and created the the adjustable pinion angle adaptor, machined out of chromoly with a 1 amd half heim joint. The unit is completely bolt in. This provides for the fastest and easiest way to adjust your pinion angle.

Pinion angle is one of the more important measurements on a lifted vehicle. The wrong angle can lead to drive line vibration and premature failure of U-joints, drive shafts, pinion bearings and even transfer case output bearings.
 

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