Help from the Brains Trust Please - dead gearbox

[Bora Sport]

Hi,

The dsg gearbox in my wife's 2010 125TDI Jetta has apparently suffered the dreaded diff rivet failure. The gearbox in the car is an LTD code. I have a JPJ gearbox from a 2007 Jetta TDI.

Does anybody have any details on why these 'boxes would not be interchangeable? My plan would be to transfer the Mechatronics unit from the existing gearbox to the replacement box so that the car would think it has the same gearbox.

Does anyone have access to VW gearbox specifications so I could determine what if any differences there are in gear ratios in the two boxes?

Any help would be greatly appreciated.

[Bora Sport]

Just an update. In case anybody is faced with the same problem in the future.

I couldn't find much advice on here or from Mr Google but after researching what I could, in the end it became a case of lets just suck it and see. My main quandary (other than would it work) was whether to replace the gearbox with the older second hand gearbox complete with mechatronics unit or use the replacement gearbox and fit it with the mechatronics unit from original gearbox. I wasn't sure whether the mechatronics unit had to match the gearbox or match the engine ecu.

In the end I just decided to fit the gearbox complete with its existing mechatronics unit. Thankfully it has worked a treat and the car has covered nearly 2,000k's since. The only noticeable difference being that it seems to hold the gears longer before changing up and doesn't drop into 6th until you are doing around 75 kph where as previously (and like my Skoda) it would be in 6th by about 66 kph. I assume that is because the car that it came out of was a 103kw motor and my wife's has the 125kw motor with more torque so it is more noticeable.

This could be fixed by a dsg tune but for now I think we will live with it. It does use a tiny bit more fuel in traffic but my wife mainly does highway driving so it isn't a huge drama.

[tigger73]

Good result!

How much did the new (second-hand) gearbox cost you?

[Bora Sport]

We first bought a 2007 Jetta diesel second hand with about 90,000k's on it. At the time I wasn't sure how reliable the dsg box would be so I bought the box years ago complete with a BKD engine. When I saw it come up on Gumtree I bought it to keep as a spare. I paid $2,000 in total I believe. It was low k's. The engine and gearbox complete has been sitting in my trailer under cover under tarps since.

Subsequently the first Jetta was written off when it was hit by a Range Rover that ignored a give way sign. We then bought the 2010 Jetta 125 TDI.

I did look around to see if there was an LTD box for sale anywhere. I didn't find one so that's why we decided to see if this one would work. I did see a JPJ box (same as the one that we put in) advertised by a wrecker for $1,699. I doubt he will ever sell it at that because by the time you buy a DMF ($1,650 from VW) and unless you can do it yourself, it will cost you at the very minimum $1,000 in labour to get it all fitted. Unless they are in really good nick the cars are now selling for around $5,000.

When I knew the box had to come out of it and to save time waiting for it to arrive, I ordered a new dual mass flywheel for my wife's car. The one in the car was absolutely shot.

Then when we pulled the gearbox off the second hand engine we found that the dual mass flywheel on it was exactly the same and in perfect condition. My mechanic said that I could've saved myself $1,350 and just used that one. He told me that if it was his car that was what he would've done. Unfortunately I could not get a refund so I decided to use the new one.

The other unfortunate thing is that I'm told that it won't fit my Skoda which now has 223,000k's on it and may need one in the not too distant future. I've actually thought of advertising the DMF for sale. If someone wanted one and wanted to save a heap of money then this would be the go. It will fit most Mk5 Golf and Jetta diesels.

I still have the engine and the remains of the gearbox from my wife's car. We pulled the clutch packs apart in both gearboxes and they were both in perfect condition. I wonder if the clutch pack had been replaced previously in my wife's car. We've done over 100,000k's in it since we bought it, so it was pretty amazing to find (with 290,000k's on the car) that the clutch pack was in near perfect condition.

My wife's car is still in good condition (I put Koni shock absorbers in it a while back). She still gets 1,150 k's out of a tank and it has plenty of grunt. If I had to drive to Sydney or Melbourne tomorrow, I would happily take it. It drives like new and my wife loves it so it was worth the effort and expenditure.

If you are still reading this sorry for the long story.