CV swapping from Passat/A4 to T25 shafts?

[davegsm82]

Does anyone know if it's possible to replace the CV joints on the T25 Driveshafts with those from a Passat/A4 DHL gearbox? I'm not sure if the splines on the end of the shafts are the same size.

I'm doing a conversion and have the old cut-off CV's from the new gearbox and they are in good condition. Rather than fitting driveshaft adapters I would like to use the larger and stronger CV/flanges from the Passat.

Cheers, Dave.

[MGP]

You need the inner cvs from the early t4 90-94 with 32 inner splines. You will also find that the shafts are too short as new diff is narrower by the width of one old cv joint.

[davegsm82]

You need the inner cvs from the early t4 90-94 with 32 inner splines. You will also find that the shafts are too short as new diff is narrower by the width of one old cv joint.

So a pair of T4 90-94 CV's will bolt up to the box if a couple of plain spacers are used?

I have the original CV's that came with the gearbox, I could in theory just hack them down with a grinder and clean them up to use the original flanges as spacers. I presume it's very unlikely that these CV's will have 32 splines on the inner part of the joint.

Dave.

[MGP]

Put the spacers on the outside otherwise the shafts will hit the top of the trailing arm. If yours is lowered you may get away with it.

[davegsm82]

It's not lowered so I'd have to go with putting them at the outsides.

If I was to cut an old CV in half would that work as a spacer? my local machine shop could accurately cut it no bother. Alternatively I was thinking of making up a couple of spacers from 100mm steel stock such as this

http://www.ebay.co.uk/itm/301225270935? ... EBIDX%3AIT

Can you recall if the outer CV's need a Recess into the mating flange? The inner ones need 22mm from the flange to the centre of the cup.

Dave.

[MGP]

On mine when i bolted the box up to the engine it wanted to sit in a position where the n/s shaft bolted up and the o/s wanted a spacer, I did try pushing the box over but it was straining the engine mounts.
For the spacer i just used the outer part of the removed cv with longer bolts

[davegsm82]

Just out of interest, did you lower your engine in the cradle/gearbox mount or leave it as stock?

Dave.

[MGP]

Lowered it by 40mm using spacers at the front and redrilling the mount bars at the back.

[davegsm82]

Spot on.

Next question, how did you go about shaving down the 15mm off the bell-housing? I'm having great difficulty getting the main input shaft bearing out as it requires a specific VAG tool VAG1582/2, I need the box stripped so it will fit onto the bed of the milling machine.

Cheers, Dave.

[MGP]

Can't help with that im afraid I did my conversion a long while before an adaptor was available so my bell housing is cut and welded.

[davegsm82]

No bother, I was thinking of doing that myself, how easy was it to keep the input shaft aligned when you came to reattach the front of the bell housing?

Cheers, Dave.

[MGP]

Easy just made a jig out of an old clutch plate that would bolt to the bell housing, hardest part was getting the correct orientation of the box.

[davegsm82]

I would consider doing this too but would need someone in the northeast who can weld alloy

I think if I was to do this, I would clamp the input shaft and bolt it to the face of the bellhousing, then cut and rotate the bellhousing round this, then re-weld at the correct position. It could almost be done in one operation i.e., mount, cut, rotate gearbox on its own input shaft, weld.

I have a large flat (8" diameter) thrust bearing that I could mount and rotate the whole gearbox while applying an angle grinder (on some sort of rotating mount) to it. Looking to buy a 9" alloy cutting disk.

Supposed to be buying an adapter plate from Tim at Ultimate Engineering but I get the impression he's mega busy and might not be able to sort it out in the time frame I require.

Dave.

[MGP]

Alloy wire in a mig works ok.

[davegsm82]

Been trying to find those CV's all over the place, not having any luck so far.

Can anyone provide a part number for them? Just to confirm, from what I can gather they are 130mm diameter with 32 inner splines apparently.

Cheers, Dave.