Discussion
It is very clear that my Monaro is needing a diff change at some point with it clonking away when I change gear. I'm just curious to get some advice on which diff most people would recommend changing to. I've heard that Wavetrac are often a choice but does that radically change the gearing at all? The wavetrac diff I've seen listed in terms of Pt No appears to be around the $1250 mark but I assume fitting is a nice wedge too.
Any help and advice would be appreciated. WP tell me that the OEM diffs are very hard to come by now, so they look to rebuild them.
Any help and advice would be appreciated. WP tell me that the OEM diffs are very hard to come by now, so they look to rebuild them.
I was talking to AAS recently about the same thing. They said the rebuild kit is around £350, plus a full days labour to rebuild. The wavetrac was highly recomended but like you said is around £1250, plus labour to get it all fitted.
They told me to steer well clear of the Truetrac kit as they've had plenty of problems with these and they just seem really low quality at the moment.
They told me to steer well clear of the Truetrac kit as they've had plenty of problems with these and they just seem really low quality at the moment.
vxr2010 said:
I’m assuming you have tried changing the diff fluid , castrol syntax lsd 75/140 totally stopped the clunk in mine and quietened down the whole drive train , monaro diff clunk is very common but easy enough to solve for about 30 to 35£ or so plus it’s an easy job to do
^^^^^^^^ what Chris said I took the oil out of mine and put castrol in and it was a different diff all together so much quieter Royal purple is not good for these 99PBATR said:
It is very clear that my Monaro is needing a diff change at some point with it clonking away when I change gear. I'm just curious to get some advice on which diff most people would recommend changing to. I've heard that Wavetrac are often a choice but does that radically change the gearing at all? The wavetrac diff I've seen listed in terms of Pt No appears to be around the $1250 mark but I assume fitting is a nice wedge too.
Any help and advice would be appreciated. WP tell me that the OEM diffs are very hard to come by now, so they look to rebuild them.
99BATR,Any help and advice would be appreciated. WP tell me that the OEM diffs are very hard to come by now, so they look to rebuild them.
I'm not sure how long you've had a Monaro but before you spend any money the first thing you need to be aware of is a good car will still clunk to some degree, there is quite a bit of drive train slack even when they were new.
I had a standard diff and it clunked with 6000 miles on the clock. I changed the oil to Royal Purple and used friction modifier. This worked for a while but when the oil was hot it started to clunk again.
Eventually I had the diff rebuilt with a 3.90 diff and a Truetrac LSD, again filled with Royal Purple. This was fine for a while but the clunking came back, and with a vengeance. After 20,000 miles the car was a nightmare to drive....clunk clunk clunk.....all the time.
I then had the diff fully rebuilt again ( believe me I was far from pleased about it )
I took my car to AAS and had them fit a Wavetrac LSD, the diff also had all new bearings, but I kept the 3.90 crown and pinion. It was topped up with Castrol gear oil.
I have done a couple of thousand miles since and its absolutely fine. I still get the odd clunk, but it's really nothing compared to what it was.
My advice is if you are keeping the car and you want it sorted out properly, use all new bearings etc, and use Castrol oil, also consider a Wavetrac they are far better made and stronger than a Trutrack, this has no effect on the gearing by the way.
If you want a dramatic change to overall acceleration consider the 3.90 diff it's well worth it.
Be aware cheap gear sets will more than likely whine.
Unfortunately I've spent a fortune on the bloody diff, so don't cut corners, you need to get it right first time.
The guys at AAS will do the job right, I highly recommend them.
John
Same as some of the comments above. If you haven't already, you must try an oil change unless you're just looking to upgrade regardless.
My diff clunked quite badly, especially after a motorway run, I swapped the oil out for Morris Lubricants LODEXOL XFS 80w140, no friction modifier was required and its been clunk n clonk free ever since.
My diff clunked quite badly, especially after a motorway run, I swapped the oil out for Morris Lubricants LODEXOL XFS 80w140, no friction modifier was required and its been clunk n clonk free ever since.
Cheers all much appreciated for the advice. I shall change the oil first and then see how we fair after that in the first instance. This one is most definitely a keeper. I've put in 60 hours work on the paint so far and probably another 60-80 hours to come. It's come up a treat. Just had a load of work done on it to make sure its tip top.
Planning on getting it to some shows and perhaps might organise a meet and attend a few next year
Planning on getting it to some shows and perhaps might organise a meet and attend a few next year
mfp4073 said:
That's good to know, I always thought 500hp was about it with a 390. diff.
If I could just get some extra cash.....oh ...here we go again......
My ute is running 670bhp and I think the 3.9 is too low and I am thinking of fitting a 3.7,If I could just get some extra cash.....oh ...here we go again......
the original diff was geared to go to the moon! hence going for the 3.9
Very surprised to hear of issues with the TrueTrac, it's a mechanical unit that's been around for donkey's years, I've given mine a VAST amount of abuse and it's fine, they're also all over the place in the US etc. but there you go.
From my understanding, the advantage with the wavetrac is if one wheel is completely unweighted the diff will still lock up, whereas the truetrac will in that scenario spin the unweighted wheel, as there's no resistance to allow the mechanism to work.
Personally despite being pretty enthusiastic with the car (last rears lasted just over 2,000 miles), I've not been in a situation where I've had a rear wheel in the air and have really wanted both wheels to keep spinning, so it isn't something that has overly bothered me
Having said all that, the car still clunks like a good'un, always has done. Monkfish noted there was a lot of lash in the pinion when they fitted the truetrac, but as it seemed to be working fine they put it back together to the same spec (this was about 6 years ago, so my memory is a little hazy of the exact wording)
Drivetrain wise it's polybushed all round, Hinson poly engine mounts, a new stiffened OEM transmission mount, an alumininium flywheel, LS7 clutch, carbon fibre one piece driveshaft, truetrac diff (standard 3.46 rear gear), harrop diff cover and one thicker BMR half shaft to minimise axle tramp. All that together and it still clunks, but it feels like a very solid drivetrain to beat on mercilessly, which is a LOT of fun
From my understanding, the advantage with the wavetrac is if one wheel is completely unweighted the diff will still lock up, whereas the truetrac will in that scenario spin the unweighted wheel, as there's no resistance to allow the mechanism to work.
Personally despite being pretty enthusiastic with the car (last rears lasted just over 2,000 miles), I've not been in a situation where I've had a rear wheel in the air and have really wanted both wheels to keep spinning, so it isn't something that has overly bothered me
Having said all that, the car still clunks like a good'un, always has done. Monkfish noted there was a lot of lash in the pinion when they fitted the truetrac, but as it seemed to be working fine they put it back together to the same spec (this was about 6 years ago, so my memory is a little hazy of the exact wording)
Drivetrain wise it's polybushed all round, Hinson poly engine mounts, a new stiffened OEM transmission mount, an alumininium flywheel, LS7 clutch, carbon fibre one piece driveshaft, truetrac diff (standard 3.46 rear gear), harrop diff cover and one thicker BMR half shaft to minimise axle tramp. All that together and it still clunks, but it feels like a very solid drivetrain to beat on mercilessly, which is a LOT of fun
SturdyHSV said:
Drivetrain wise it's polybushed all round, Hinson poly engine mounts, a new stiffened OEM transmission mount, an alumininium flywheel, LS7 clutch, carbon fibre one piece driveshaft, truetrac diff (standard 3.46 rear gear), harrop diff cover and one thicker BMR half shaft to minimise axle tramp. All that together and it still clunks, but it feels like a very solid drivetrain to beat on mercilessly, which is a LOT of fun
Does the one piece prop do away with the rubber doughnut?I went for a kaaz diff and love it. As above, also have proper engine and trans mounts.
fred bloggs said:
Does the one piece prop do away with the rubber doughnut?
I went for a kaaz diff and love it. As above, also have proper engine and trans mounts.
Yep, it's one tube from gearbox to diff.I went for a kaaz diff and love it. As above, also have proper engine and trans mounts.
It's quite large in diameter (4 inches I think?) to avoid resonance issues, so you have to grind back the exposed excess thread of the seatbelt bolts as they protrude in to the tunnel. That and possibly hit a heat shield with a hammer a bit, I can't quite remember.
It doesn't really make any difference to the clunk, I had assumed as the rubber doughnut had perished that was related, but it's not made much difference.
I got mine from DriveShaftShop in the US. If you have an account on the LS1GTO forum I believe they'll give you a 10% discount too. Still not cheap mind, but if you use some man maths to also subtract the cost of a replacement OEM driveshaft, it's.... still expensive
But, why replace when you can upgrade, right?
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