at my wits end!! help!!

[wayne4776@hotma]

hi guys,really need your help on this one,94 td non intercooler.i,ve got a kind of judder/misfire when light accelerating,tried driveshafts and wheel balance no difference.I,m thinking along the lines of misfire under load now,i service it every 3k and it gets everything it needs.runs perfect and revs perfect when stood still but i,m thinking it might be a slight miss when i,m accelerating,doing my box in!! do they suffer with injector faults or pump?? p.s its done 155000 miles.(still running it in)

[kenney]

Engine code?

[wayne4776@hotma]

of course!! sorry,its an aaz.

[Crasher]

It could be diff rivet failure, especially if it is worse in second. I have had an AAZ G3 for years as a run around for the shop and to lend to people (like when VAG are trying to find the bits I have ordered that they say they have so I take the car to bits and the part don’t turn up, sorry for the bitter outburst!) and they don't tend to suffer misfiring although mine has played up twice, one the head dropped a pre-combustion chamber and another time it did the usual trick of throwing the front crank pulley off.

[wayne4776@hotma]

i,m a mechanic too but i,m stumped with this one,when i changed driveshafts i checked for excessive movement in diff but ok,it almost feelings like an engine mount, when you are accelerating and its throwing the driveshafts out,if you know what i mean? but i,m thinking of every option,the engine is perfect when revving it freely,thats why i,m strugling to get my head around it misfiring.and it does it worse when cold and def worse in second.but it does it all time when accelerating lightly.

[Crasher]

Really does sound like it has thrown a rivet out; you won’t pick this up by checking free play on the diff. I know it is a long shot but I suggest pulling the box, removing the end cover, remove the left drive shaft cup, extract 5th gear and pull off the case so you can take a look. All you need is a decent puller, 27-mm hex key and the tool from VW to remove and reset the 5th gear operating rod. If you leave it, the rivet will punch out of the box and write the casing off.

[wayne4776@hotma]

cheers for your help! reall appreciate it,think i,ll look for a replacement box and give that a try.i,m up for trying anything at the moment! its a minter apart from that,not even looking like rust anywhere,good enough to show really,i,d like to get it right.thanks again matey.

[Crasher]

Mine is battered and rusty but drives well, we call it The Tractor. I had to put a good used box in mine recently. I lent it to someone and they had a problem finding reverse gear and stripped all the teeth off the idler wheel and both shafts so repairing it was not cost effective. Finding a used box proved to be a major problem and in the end I used a box out of a 1.8 90PS petrol model as it was fitted to the AAZ G3 at other times and in certain markets. It revs a little high in 5th but is otherwise OK. Unfortunately diff rivet failure is so common that decent used 020 boxes of any type fetch good money second hand.

[wayne4776@hotma]

hi crasher, i,ve looked into the rivet issue,and couldn,t beleive the amount of people it has happened to on the net.most seem to be on t reg vehicles,do you still think it could affect mine with it being a 1994 td aaz? i,ve found a box thats done 70k for £120,but was thinking of having mine rebuilt with the nut and bolt kit and new bearings.what sort of money do you think a trans specialist would charge if i took box out?

[Crasher]

It started happening about three years before T reg, but not the T reg you are thinking of, the one before that in 1978! The 020, then 02K box has been popping its pin and rivets since about 1976-77 and still they insist on doing it the same way. They deleted the tall rivet around 1996 and fitted the circlip to the diff pin to prevent it sliding out (even though the grove for the circlip had been there since the 70’s) but still used the rivets. Yes, pull your box apart and fit the rivet kit but there is more to it than that. Accurately costing repairs to the box is impossible as everyone has their own way, I charge about £1k to rebuild an 020 fully including all bearings, gaskets, syncro cones, seals etc. Other people charge half that for less than half the work, it is a very grey area.