Fitted a LSD to my e85 Z4 3.0

Yorkie Z said:
Fanatic said:
Yorkie Z said:
On I side note my old E46 M3 used to really clunk, thing was like a bloody tractor...
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Yes this is something I have heard
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Just a thought. Put the car in first gear and jack both wheels off the ground. Then turn them both ways by hand to check for a clunk.!!
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But the thump is only when engaging the gear. If without moving I disengage and engage again there is no thump.
 
Yeah I read somewhere that it was like 0.30mm, that's a huge clearance compared to the all the rest. As you say it's a clutch type thou. :thumbsup:
 
Must be taking up the free play somewhere. I would jack it up and and turn the wheels. Put the car in 1st give it a few goes then stick it in reverse. Obviously with the car turned off :wink:
 
Not in practice. In theory I sent grinspeed a mail and he said that if there is a thump there is something incorrectly set. A bit general but sent him sime more info, maybe he can pinpoint which setting it is. :D
 
That's good least he's on the case. Was thinking the guy that fitted yours can't have had 3 cars with identical backlash 0.08, it just would happen like that. My friend has fitted an M factory diff into his Z and had a slightly diffrent reading to what I had on mine. Think your mechanic may not be telling the truth :thumbsdown:
 
I have a Mfactory lsd in a 3.07 diff, when installed the backlash came out towards the upper limit 0.12mm (the official tolerance is 0.06mm-0.14mm), however, to quote Birds Auto, "the backlash can be set as high as 0.20mm", this is obviously the m3 setting and is really clunky.
Mine being set at 0.12mm is clunky but i would not describe it as a thump, it clunks putting it in gear & also when coming on & off the power in 1st & 2nd, but you hear it more than feel it! Hope this helps :thumbsup:
 
jyonaudl said:
also when coming on & off the power in 1st & 2nd,
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This is how you can hear backlash, but that is the backlash of the total system, so drive axles, crown/pinion, internal diff gears, propshaft couplings, gearbox gears etc.
I had 0,08mm backlash btw.
 
Ok so I finally managed to visit the garage to check these out. Apparently there is a "movement" of the gearbox section where the drive shaft is linked to it. As they explained the backlash from the gearbox was there but now because with the lsd the diff is "tighter" the sound is heard.

Solutions apparently are:

A) Get used to the efing sound
B) Put the free diff back on which does not create the sound as it is free it "absorbs" some of the movement
C) Look for a tranny specialist to open the gearbox in the back and see how to make the gears there tighter.
:headbang: :headbang: :headbang:


Sorry if some terminology is not spot on, my auto mechanic english is not sooo advanced.
 
Did you check the condition of all differential mounting. Prefacelift models had a rear diff hydro-mount. Eventually they get torn, liquid goes out and you get more and more play and in the end you also get a thump sound. Put the car up on a lift, and check it. You put the handbrake on, first gear and slowly release the clutch. You will need another person under the car to check for the movement and thump.
 
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