2WD CONNVERSION MURCIELAGO DIFF ISSUES

Need advise on parts

 

Did the 2WD Conversion & loved it but broke Sun gear in Diff

 

Has anyone had an aftermarket one built or are there any oem replacement?

 

http://www.another board/vbforum/at...-simple-908.jpg

 

Thanks in advance

 

 

 

 

 

 

 

 

Need advise on parts

 

Did the 2WD Conversion & loved it but broke Sun gear in Diff

 

Has anyone had an aftermarket one built or are there any oem replacement?

 

http://www.another board/vbforum/at...-simple-908.jpg

 

Thanks in advance

 

 

 

This is the exact reason I went back to AWD. I keep waiting for MORE people to start having this issue. I popped two different 'Sun gears' in the differential from this. Trust me, this is a REAL problem with the RWD setup on PRE lp640 cars. Its not IF its going to happen to you, its WHEN. Trussssst me I know. The 02-06 differentials are weakest at the 'sun gear' aka output shaft from the planetary gears.

 

I tried in VEIN to get JUST the output shafts, but no luck, they want to send you the whole diferential carrier. I even contacted the manufacturer and they were of no help.

 

The only fixs:

 

1. Replace the differential with another 02-06 murci diff, and go back to AWD, or in about a year or so, you'll break the replacement one. (This is a FUN job, not, you have to pull the whole differential out of the car.)

2. Replace the output shaft in the guts of the differential, this can be done with the differential case in the car, but you MUST remove the side covers, and back cover, and extract the carrier and ring gear (all 1 unit). go back to AWD after this, as again this fix only puts you right back at weakest link point.

 

Ultimate solution

3. Replace the rear oem 02-06 differential with an 07+ differential (NOTICEABLY BETTER design). I have a spare one sitting on my shelf just waiting for the oem one to fail again (would be my 3rd time). But since I put it back to AWD, I am guessing I wont have this problem anymore, but buying the 07+ rear differential for $4500+ship as a spare is CHEAP insurance. I am so good about doing both those jobs, I put my skills against any lambo tech

 

Good luck, and I tounge in cheek say "Welcome to my world." Least YOU have someone who has been there, done that... I had no one. Sadly/Happily, I can say I know this problem like the back of my hand and how to fix it.

 

 

Could someone explain in detail how the 2wd conversion and sun gear failures are connected?

I would assume it's becuase the load that used to be slpit is now directed through one axle. If the car was 2wd the factory would have uncovered it during R&D and beefed it up...which it sounds like the did even for 4wd on the LP640.... leads one to beleive that if 60HP increase led to a redesign in the diff, Lambo knew it was at the limit in the 6.2

Has anyone with AWD had issue with damaging their Sun gear?

I would assume it's becuase the load that used to be slpit is now directed through one axle. If the car was 2wd the factory would have uncovered it during R&D and beefed it up...which it sounds like the did even for 4wd on the LP640.... leads one to beleive that if 60HP increase led to a redesign in the diff, Lambo knew it was at the limit in the 6.2

 

You nailed it. Even if the front takes 20-30% of the load (not say 50/50), its enough to spare the output shafts (these are internal to the planetary gears and extends outside of the transmission) from load failure. However, when there is no 'little helper' the rear differential takes the whole load. In both cases it has lasted about 1 year before failure in 2wd mode.

 

Has anyone with AWD had issue with damaging their Sun gear?

 

YES, coming directly from my lambo tech, however, its generally EGEAR cars as there is a LAUNCH control feature, that will significantly overwhelm the differentials after a few uses, and if the tires 'hook' its not long before the differential pops these planetary output shaft gears.

 

AGAIN, this is on the 2002-2006 cars, as the design was noticeably improved (they stopped drilling a HOLE directly in the center of the shafts (removing probably about 20% of the units sheering strength), and went with a SOLID CORE approach. on the 2007+ differentials. Again, I have the priviledge of knowing, because I have both units in my garage

 

For AWD cars, dont use EGear launch control, OR on Stick cars (dont do clutch dumps) and you likely will never see a failure.

 

2wd cars, unless you arent putting miles on them, OR are driving it like a pussy (not being insulting, I drove my car like a pussy on the way home after purchase, and a few weeks after... then I started driving it like a lamborghini), I think its going to eventually occur again ON PRE lp640 cars.

 

My 2 cents, I actually gain nothing from sharing this, other then historically, its what I do, I share what I learn, and I enjoy it when others do the same.

 

Thanks!

 

Jon

 

You nailed it. Even if the front takes 20-30% of the load (not say 50/50), its enough to spare the output shafts (these are internal to the planetary gears and extends outside of the transmission) from load failure. However, when there is no 'little helper' the rear differential takes the whole load. In both cases it has lasted about 1 year before failure in 2wd mode.

 

 

 

YES, coming directly from my lambo tech, however, its generally EGEAR cars as there is a LAUNCH control feature, that will significantly overwhelm the differentials after a few uses, and if the tires 'hook' its not long before the differential pops these planetary output shaft gears.

 

AGAIN, this is on the 2002-2006 cars, as the design was noticeably improved (they stopped drilling a HOLE directly in the center of the shafts (removing probably about 20% of the units sheering strength), and went with a SOLID CORE approach. on the 2007+ differentials. Again, I have the priviledge of knowing, because I have both units in my garage

 

For AWD cars, dont use EGear launch control, OR on Stick cars (dont do clutch dumps) and you likely will never see a failure.

 

2wd cars, unless you arent putting miles on them, OR are driving it like a pussy (not being insulting, I drove my car like a pussy on the way home after purchase, and a few weeks after... then I started driving it like a lamborghini), I think its going to eventually occur again ON PRE lp640 cars.

 

My 2 cents, I actually gain nothing from sharing this, other then historically, its what I do, I share what I learn, and I enjoy it when others do the same.

 

Thanks!

 

Jon

 

Good to hear from you Jon. I guess I'm relieved to hear that I won't have to worry about the Sun Gear now that I've went back to awd. But are Raging & you the only two with this problem? I would imagine there're gotta be at least half a dozen Murci owners here who converted to RWD???

 

What are you referring to SUN GEAR? You mean spider gears?

Good to hear from you Jon. I guess I'm relieved to hear that I won't have to worry about the Sun Gear now that I've went back to awd. But are Raging & you the only two with this problem? I would imagine there're gotta be at least half a dozen Murci owners here who converted to RWD???

 

Yeah, I don't know. I can't imagine that we would be, but I personally don't know of any others who have had this issue, but with me having it happen twice with 2 different differentials, its not likely that I just got TWO factory defects. But again, the 07+ cars are FAR LESS likely to have this probelm, so it will have to be RWD on 02-06 cars, and Egears being the most likely to have the problem because of the harshness of the geaar shifts.

 

What are you referring to SUN GEAR? You mean spider gears?

 

Yeah, I just used the other guys terminology, I've not ever really refereed to them as Sun gears, but sounds cool, so used it. I know it as the spider gears as well, I thought PERHAPS spider gears that have OUTPUT shafts were called SUN GEARs and that why I used the terminology. Keep in mind there are effectively 2 types of 'spider gears' in the tranny (4 total gears), two of them are your typical 1/2 circles rotating on a shaft, but the other two, have output shafts that extend outside the differential and are the basis for which the output flange attaches to, and then the stub axles attach to those and that ultimately attach to the wheels.

Any update on this issue? Any more with 2WD conversions have this issue on 1st gen Merci's?

 

I don't dog my cars, anymore. I'm over that. Occasionally drive spirited, but in general, I like working on my cars and doing the sunny day cruising thing. So would this blow my sun gear with 2WD?

 

I would like to switch to 2WD to save the front wheel drive parts from wearing, lower the weight of the car, and make slow speed cornering feel lighter.

I felt the same way Stimpy but after a talking to a few people, seems the general consensus is don't do it.

Any update on this issue? Any more with 2WD conversions have this issue on 1st gen Merci's?

 

I don't dog my cars, anymore. I'm over that. Occasionally drive spirited, but in general, I like working on my cars and doing the sunny day cruising thing. So would this blow my sun gear with 2WD?

 

I would like to switch to 2WD to save the front wheel drive parts from wearing, lower the weight of the car, and make slow speed cornering feel lighter.

 

 

I've done a write-up or at least a comment about 4wd to 2wd to 4wd again. There are pro's and con's to both, so please dont think you get this 'best of all worlds' by going to 2WD, you dont. With that said, I am definitely NOT hear to rain on anyones parade who loves the 2WD conversion, I did it myself and enjoyed it for a couple of years (just blew 2 differentials in the process), and now with the lp640 (stronger), I could go back to it, but I'm still too nervous to do it. I know Whiteout has a vested interest in this conversion as he sells the parts needed (which if anyone does it, he's got my vote, as he is the guy I got my parts from), and I guess if he is honest (and I certainly dont know him to lie), he might know of more blown diffs from this conversion IF they happened, but I dont know if any have. Its a bad design, I drive my car like its a lamborghini, never abusing it, but definitely keep it performing!

 

The good thing is, lp640 differentials are confirmed to work on the early gen murci's so you have all options available to you if one breaks.

 

Thanks,

 

Jon