Need help solving an issue

Hey guys I have a 2010 d40 4x4 manual and I'm getting vibration, it's begins at around 40km/h on the steering wheel and then transfers to the entire vehicle when the speed is increased. I've changed 2 cross members, front wheel bearing,cradle bushings,rear diff pinion seal, swapped tires and rims, align, camber,castor and rotated the tires. The firm doesn't know what is causing it ,now they are saying it could be the flywheel or drive shaft. Any advice would be appreciated.
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I'd jump underneath and give the drive shafts a wiggle - you could have a loose uni or bearing. They should be tight enough to work in a convent.

a test if it is the flywheel causing this vibration at speed is to get up to the speed where the vibe comes in and then wack the gear into Neutral, this should free wheel or should i say get the engine rpms down to an idle rpm.
other symtoms ; bent drive tail shaft / badly worn uni joints at shaft ends.

can you disconnect the front shaft to rule that one out. with every car that iv'e had with a crook drive shaft, the vibration frequency is quite high, unlike a wheel balance vibration, as the drive shafts will be spinning around 3 to 4 times quicker than the wheels

ericcs said:

can you disconnect the front shaft to rule that one out. with every car that iv'e had with a crook drive shaft, the vibration frequency is quite high, unlike a wheel balance vibration, as the drive shafts will be spinning around 3 to 4 times quicker than the wheels

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Took out the front shafts and drove it and the vibration was still present.

Have you given the rear drive shaft a wiggle yet? And I wasn't thinking of Murray or Emma or Lochie.

You haven't mentioned changing shock absorbers. If they haven't been changed and are still the factory items, they could be too soft allowing the wheel to bounce when it shouldn't be. I don't suppose you have got a camera like a gopro or similar that you could attach to the outside of the vehicle and film one wheel at a time to see if any of them are bouncing excessively?

bods said:

You haven't mentioned changing shock absorbers. If they haven't been changed and are still the factory items, they could be too soft allowing the wheel to bounce when it shouldn't be. I don't suppose you have got a camera like a gopro or similar that you could attach to the outside of the vehicle and film one wheel at a time to see if any of them are bouncing excessively?

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Change my both front shocks 2 months after I bought the Navara from the dealer. It came with "a bad" shock from Thailand they said. I've had these on for about 5 years now so I think it's due to change. The vehicle feels a bit unstable when hitting the rough stuff. Thanks mate for the info.

Old.Tony said:

Have you given the rear drive shaft a wiggle yet? And I wasn't thinking of Murray or Emma or Lochie.

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It has a very little play like 5cm turn on each side.

Whoa, 5cm of movement in ANY direction in the drive shaft is huge! Can you describe this motion a little better - is it rotating the drive shaft, or moving the shaft up/down or left/right?

Sorry 5cm Rotation of the drive shaft , no movement left or right and limited movement up and down.

5cm of rotation is significant. I'll check mine later, I'm sure mine is much less than that - although I've had my rear diff rebuilt with new gears a couple of months ago.

Did you change the ratios? I know you're an expert when it comes to the d40. Thanks for the info on my issues.

I left the ratio as standard. I actually changed tyre size once and found the slightly taller gearing caused economy and power problems. Went back to standard size and all was good again.

I might have considered a small drop in ratio in order to use larger tyres (so that the ratios cancelled themselves out and the final actual road ratio was still the same) but I would have to have changed the front diff as well (of course) and didn't want to mess with it at the time.

Old.Tony said:

I left the ratio as standard. I actually changed tyre size once and found the slightly taller gearing caused economy and power problems. Went back to standard size and all was good again.

I might have considered a small drop in ratio in order to use larger tyres (so that the ratios cancelled themselves out and the final actual road ratio was still the same) but I would have to have changed the front diff as well (of course) and didn't want to mess with it at the time.

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Awesome info, Old.Tony

Hey mates found out what was causing my issue,it was the bushing in the steering rack.