Thread: driveline backlash

Originally Posted by mike 90 RR

Backlash

This is my understanding of diffs (at the risk of being flamed via others .. So correct me if I am wrong)
Based on a "open center" type only (RRC)

Your diff could be perfectly fine ...... Just old with too many k's on it
The face of the teeth of the Crown & pinion have just worn down = play
The face of the teeth of the Spider gears have just worn down = play

This puts more space between the edges of the corresponding teeth where they join (Crown tooth to pinion tooth)

Also the center Hemisphere could have some wear in it's pin joint

To adjust the lash is not (most probably) the answer, as you set the crown "Center to pinion" ..... If the diff "whines" ... Then it needs to be checked and have the crown & pinion re-adjusted ... As it needs to run face to face (of teeth) "centered" .... The amount of backlash is governed by this visual setting

So in short /// If the diff doesn't whine (no gear noise) ... answer is NO .. Backlash setting is fine

If you wish to remove more backlash ... then the answer may lay in the purchase of "All new gears" for the diff = $$$$

Hope it make sense


Mike

Dont want to hijack this, but some might be able to give me a Pauline Hansen on this.

Is there an explanation on why my rear propshaft moves 5 degrees and my front moves 30+ degrees yet?????
Mike has seen this. Move between D and R, the front shaft rotates more than the rear by a long way!!
I am assuming this is diff related, however there is no noise or whine coming from the front at all.

Mines the same. Pat

backlash is about 60% from the center diff my 200tdi fender had 280 000 ks and the backlash was really bad it was a pain in the **** .i fitted a part time conversion kit in it and it eliminated 80% of back lash so that has to say some thing

due to the windup of the center diff tending to let the slack turn up in the front shaft as opposed to the rear....

But it does sound a little off to me...

You shouldn't get wind up in the center diff until it is locked, the center diff is used on constant 4wheel drives to prevent wind up.

Originally Posted by lambrover

You shouldn't get wind up in the center diff until it is locked, the center diff is used on constant 4wheel drives to prevent wind up.

My classic is a '93 so has BW transfer with viscous.
The centre diff is always locked. The rear output shaft slips directly onto the CD which is installed inside the lower chain sprocket.The viscous slides onto the other side of the CD and the yoke for the front propshaft slides onto the other side of the viscous, which then splits the torque output 50/50 front and rear. With the BW transfer, if you take either driveshaft off, you still have drive to the remaining shaft.
In a normal transfer, you need to manually or electrically lock the CD or you will get no drive anywhere.
So if there is any excess lash in either diff, your propshaft would still take it up until it loads.
Mine however seems a little excessive.
I just answered my own question.... i think.......

with a normal transfer case there is no center diff, but there has to be a selection be it manual or electronic which actuatates a selector within the transfer to engage 4x4, transfer case' with the center diff just allows for different speeds traveled by the front and rear wheels which is needed on hard surfaces.

Originally Posted by lambrover

with a normal transfer case there is no center diff, but there has to be a selection be it manual or electronic which actuatates a selector within the transfer to engage 4x4, transfer case' with the center diff just allows for different speeds traveled by the front and rear wheels which is needed on hard surfaces.

Ummmmm... if there is no centre diff in a normal transfer case, then why is the lock referred to as a "Centre Diff Lock"????