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[jonathanhann]

I know its been done on here loads of times, but I just got some 2" lift blocks for my 1994 xj 4.0.

The instructions say fit the blocks so that the tall edge is at the back, in effect tipping the axle pinion up towards the transfer box. There is even an F indicating front on the narrow end of the block.

So is this definately right, that when lifting the back by 2" the pinion should be positioned pointing more up towards the floor?

Its just that its got a humming or drone vibration at 25mph.

Should i drop the transfer case a few mm?

Or is this all wrong and the pinion should face downwards more with a lifted rear?

Also I havent fitted the front lift yet so its a bit of a dragster, but surely this wouldnt make a differance, would it?

Thanks in advance.

[tim_aka_tim]

Definitely needs the point up, with thin end at the front. With 2" of lift, the angle should be very slight, 2° tops. Perhaps you have a buggered UJ that didn's show up with stock suspension.

[greggmo]

recon you will have to drop the tranny a touch. like tim says also check the uj's mate.

[JamesH]

Tilting up only applies if you have a slip yoke eliminator fitted. I'm assuming you don't, in which case they should be in the other way around. With the stock driveshaft setup, the output from the transfercase and the pinion of the rear axle should be parallel, hence using the shims to tilt the angle down.

However, usually the rear angle only needs to be corrected if you have fitted shackles to lift the rear as the shackles will normally tilt the pinion up.

A thread not so long ago included diagrams to illustrate what I'm trying to say, have a look through the old posts.

[GermanXJ]

Try this link. http://madxj.com/
Go to the TEC section scroll down untill you see the driveshaft tec section.

[jonathanhann]

thanks for the replies, nothings ever straight forward!
And to top it all off, I just been out to check them with a torch and found a big rust hole in the boot floor! ha ha. what a game!

Think I will measure the angles at work.
Its only at 30mph, nothing above, nothing below.
we got an inclinometer at work, think I will have a check with that and see how much differance there is, then try and get them parallel.

[garyf]

if its only slight and is down to prop angles it should get worse when you accelerate hard, the nose of the diff is driven up slightly when you do this and therefore should make it worse, if you don't get this I would look elsewhere

[jonathanhann]

update for vibration, full marks to jamesH, after measuring the driveshaft angles at the transfer case and at the axle, I found the transfer output shaft to be at -3.5 degrees(pointing down) , and the axle pinion at 6.5degrees(pointing up).

So fitting the blocks as per instructions and putting the thin end at the front to tilt the pinion up, it has over compensated the angle.

After a late night at work I have fitted them the other way round, thick end at the front to lower the pinion nose. This resulted in -3.5 at the transfer case and 3.6 degrees at the axle.

Road test confirms to have eliminated the vibes.

Handy to know for someone in the future, thanks for all the replies.