Q2 differential - 'must have' upgrade for 147GTA/156GTA/(V6)GT

[shiny_car]

hey guys. whilst i don't contribute much in the forums, i haven't noticed people referring to the Q2 diff. so i thought i'd provide my 5 cents worth. i prepared the following for 'elsewhere', but thought i'd post it here too. it is, by no means, the last word on the subject, so please don't view it as dogma. nor is this intended as 'advertising' in any way; i have no affiliation whatsoever with the car industry or supply of this diff.

basically, i want to get the word out amongst Alfisti. too often, i am hearing the same story over and over, that the diff has blown (i am merely an enthusiast, not a mechanic, so probably only hear of half the problems), and it's going to cost thousands to repair. there are also strange stories of alfa mechanics/dealers who have not heard of the Q2 or seen diff failures; i don't find this reassuring.



unfortunately, the standard diffs in the 3.2L 6spd gearboxes are 'fragile', and well known to fail. this can occur even in a 30K km car - has happened! moreso in australia, so whether that relates to the higher ambient temperatures is unclear; though it appears they are also failing in higher km cars in the UK - frequently! you just have to read the stories in the Alfa Owner forums, which occur weekly: http://www.alfaowner.com/Forum/alfa-gta/

it is the smaller planetary gears that tend to fracture, and when they do, the fragments commonly enter the gearbox to take out gears inside there too. also known to blow holes in the gearbox bell housing! at a minimum, can be $3K to fix, and possibly up to double that. plus time off the road, that sinking disheartening feeling, and anger/frustration.

commonly, it occurs when accelerating from standstill, full/near-full lock, and not necessarily hard acceleration. so, you could be pulling out of a street at a T-intersection...then clunk.

the Q2 is a Torsen style LSD, that is far more robust. NO reports ever of these failing, to date. not only are they stronger, the improved performance is very significant. much reduced torque steer, and far better power-down acceleration. i now drive with the ASR switched off, and let the diff do its magic. far less understeer, and i can use the accelerator to help 'steer' the car; feed in more power, and the car tucks its nose in, as the outside wheel puts more power down. quite the opposite of the usual FWD manners.

many have fitted them, and mostly as prevention, rather than waiting for the original to break! i had mine fitted when the car was only 10K km old.

they are an official alfa part. they are an option on the diesels over in europe, including the GT and 147. they are available through an alfa dealer, or if you're in sydney, people recommend Max Oddi as a better choice - an independent alfa specialist mechanic.

Max can usually supply them for about AUS$700, subject to the oz dollar. or you can buy one yourself from EB Spares in the UK, who offer excellent, reliable service (no risk buying from them):
http://www.ebspares.co.uk/news77.htm
http://www.ebspares.co.uk/alfa_147/Q2_diff_for_6_speed_manual_cars/

an alfa dealer will charge around $900~1100 for the diff.

installation takes about 8~10 hours labour, so costs another $1000~1200, depending on who's doing it. you also need to pay for new bearings (cannot remove originals without potential damage), and seals, and gearbox oil. so the all-up cost, supplied and fitted, is around $2200, give/take a few hundred.

it is probably the best upgrade you can do, and definitely worth doing as soon as you can afford it. within 6 months would be my strong feeling, just for peace of mind.

note, in the past, even if the original breaks whilst under warranty, you will be extremely lucky to be fully covered. ATECO have typically baulked at the suggestion it's a manufacturing fault; they have had dealers download the car's data log to assess how often the car has been 'redlined', and subsequently claimed 'driver abuse' as the cause. you might only receive half the cost as compensation, at best. it depends how lucky you are, and the history of the car (which you may not fully know). i don't know if their stance on the matter has improved or not.



hopefully this helps prevent more horror stories, and keeps our cars trouble-free and enjoyable!

[Jekyll and Hyde]

Funny that you say this, when the Q2 diff came up in the post a couple below yours (GTA known issues), for exactly this reason!  If I were to buy a GTA, it would indeed be one of the first things I did, as the torque steer is just frighteningly prominent.... not to mention it would cop a bootful quite often with me driving 

[Sheldon McIntosh]

Excellent post shiny_car, thanks for that.  I had noticed how many references were made to the Q2 on my brief visits 'elsewhere', and was surprised it hadn't really cropped up here at all.

Thanks for that.

[TFJ100]

As someone who has suffered from this myself (after a harmless 30 km/h right hand turn), here is some advice for anyone who owns or is going to buy a 2nd-hand V6 Alfa of the types described (including GTV V6, which is what I have):

Replace the diff with a Q2 - now!

If (or should I say when) the diff blows, you will be up for another $2,000 to replace the bell housing, so you may as well get it done before it happens. You can then be happy you have done a nice upgrade.

Otherwise, listen carefully when you drive your car. That ticking noise you can hear is the clock running down before your diff decides to pack a sad on you, and your wallet.

One other note - when your mechanic dives into the diff, they will probably recommend a new clutch - so you may as well budget for that. Mine needed a new one anyway.

[shiny_car]

geez, i haven't heard of a GTV diff blowing before. actually, not true - i think someone's in sydney has blown as well.

most seem related to the 147GTA, and particularly in australia. many speculated reasons for this, including combination of ASR-VDC (trying to curb wheelspin at the same time that power is going to the wheels), climate/high temps, cheaper car that is therefore in the hands of younger drivers (read: hoons  ), higher mileage (compared with the newer GT).

whilst the numbers seem higher in the 147GTA, there are definitely diffs breaking in the 156GTA and 3.2L GT as well. and obviously the odd GTV too. so yes, it can be a matter of 'when', not 'if'.