Hard thump underneath

616 Views 4 Replies 2 Participants Last post by TommiT, 2 mo ago

qurtuba

Discussion Starter · 3 mo ago

Hello all. So today while driving to work I heard and felt a hard thump underneath the car, which sounded to me like the transmission or transfer case or something scary like that. It happens every few minutes while driving, kind of like an engine misfire but the sound is very mechanical and like I said is coming from the tranny area. I'll get it looked at this weekend and hopefully come back with good news.

Save

1 - 5 of 5 Posts

TommiT

· #2 · 3 mo ago (Edited)

Propshaft / driveshaft centre bearing thin rubber surround tearing?

Common issue on Gen 1 T1s and T2s if so.

Easily fixed in half an hour or so for no cost.

Look up "The Jimi Fix" spelt exactly as typed.

Alternatively, if it's happening at about 38-40 mph as you are cruising along on a light throtle and the road starts to rise so the gearbox changes down from 5th to 4th then it's the gearbox valve chest, another common Gen 1 issue.

Save

qurtuba

Discussion Starter · #3 · 3 mo ago

TommiT said:
Propshaft / driveshaft centre bearing thin rubber surround tearing?

Common issue on Gen 1 T1s and T2s if so.

Easily fixed in half an hour or so for no cost.

Look up "The Jimi Fix" spelt exactly as typed.

Alternatively, if it's happening at about 38-40 mph as you are cruising along on a light throtle and the road starts to rise so the gearbox changes down from 5th to 4th then it's the gearbox valve chest, another common Gen 1 issue.

Thank you for the reminder about the centre bearing. I'll check it out and pray that that is actually the problem here and not anything wrong with the gearbox.

Save

qurtuba

Discussion Starter · #4 · 2 mo ago

Hello all. An update on this issue. Sorry TommiT but the centre bearing has been found innocent of any failures. However, along the way during diagnosing the problem, the rear axle shaft boots were found to be in a sad state, with the grease having leaked out completely and the shafts running totally dry. My friend the mechanic first thought that he'd have to replace the complete axle shaft assemblies, but upon close inspection he determined that the shafts themselves were still good and just needed new boots and grease. Another issue he noticed was a bushing on the rear diff. that had failed. Replaced that. Rear end (the Touareg's) is now in tip top shape.

BUT! the problem of the scary thump still persisted. So (after a personal "D'oh" moment) I took a VCDS scan. I immediately noticed an issue that wasn't there before (see attached pic). G28 sensor is giving intermittent faults. Weird thing is, the difference in price between an OE part and aftermarket ones (FCPEuro lists VNE as OE) is huge, US$48.29 for the VNE vs. US$229 for the genuine VAG part. So I might get a used genuine part. I should know by today if one is available.

See less See more

Save

TommiT

· #5 · 2 mo ago

Glad to read you are on the way to getting things sorted.

Save

1 - 5 of 5 Posts

Top Contributors this Month