Vibration

[Hoppy11]

When I first got the Hummer replica driving I had a vibration between 20 and 35 km/h, we found that it was coming from the small prop shaft between the 4 speed auto and the MK divorsed transfer case. the shaft was perfectly in phase, the sharp angle of the shaft was the problem. We fixed the problem by fitting a 20mm spacer below the bracket on the shaft side bringing the shaft more level, cured the problem, we then removed the transfer to rebuild it ( new bearings and shit) when we put it back in the vibration was back, every thing was as it was before??. A new 10mm spacer was added to the 20mm one, the vibration went away. It's been like that for 2 months, about 4500km's. I went wheeling today and the vibration was back, same speed as before, after much fucking around with spacers I removed the 20mm spacer and left the 10mm one in, the vibration is gone. My questin is WHAT THE FUCK IS GOING ON!!!!!
the attatched clip is of the shaft before being spaced.
Hoppy

[Hoppy11]

Does anyone know if the gearbox mount on divorsed transfer Patrol's is solid or rubber???
Hoppy

[lay80n]

Your flanges should be parallel to each other so the uni's will opperate through the same angle, therefore cancelling each other's accelleration and decelleration phase.

Layto....

[smashcrab]

One end of the shaft should be rotated 90 degrees to the other.
Your mising a bolt (posibbly two) on the tcase flange.
That is one short shaft, so any allignment issues with he unis will be more noticable, balance issues will be less noticable.

[Hoppy11]

One end of the shaft should be rotated 90 degrees to the other.
Your mising a bolt (posibbly two) on the tcase flange.
That is one short shaft, so any allignment issues with he unis will be more noticable, balance issues will be less noticable.

all the bolts are in, the pic was taken when it first went in
Hoppy

[WRXZook]

One end of the shaft should be rotated 90 degrees to the other.

That is not right. The yokes on the shaft should be accurately in line with each other. Whoever made the shaft would/should have checked it was properly aligned. From the picture it looks right.

As lay80n said, the flanges should be parallel. Hard to tell from the picture but it looks like the TC input shaft is not parallel with the transmission output shaft. Use the rear of the extension housing as an imaginary flange when checking whether it is parallel with the TC flange.

Some don't worry too much about this alignment, but it is important, especially when trying to eliminate/reduce vibration (and less vibration extends driveline component life).

I'm sure you would have, but have you checked the uni joints and also engine/transmission mounts in case something is moving more than it should.

[KiwiBacon]

Layton & wrxzook have the answers.

Where were you putting these spacers?

[Hoppy11]

The flanges are parallel, the spacers were put under the bracket on the shaft side (see pic), this will raise tthe side of the transfer keeping the flanges parallel ( we checked) by raising the TF one this side it levels out the small shaft. There is no movement in the TF or gearbox, the only movement could come from the gearbox rubber mount which is the original Holden one, I thought the original Nissan gearbox rubber may be harder, cause this is the only place where there could be movement tat would put anything out of parallel, not to sure, I'm going to give the truck a run at the same place tomorrow and see if the vibration comes back.
Hoppy

[KiwiBacon]

Are the two shafts (gearbox and transfer) completely parrallel?

They don't look it from the photo, but photos can be deceptive.

[Hoppy11]

Are the two shafts (gearbox and transfer) completely parrallel?

They don't look it from the photo, but photos can be deceptive.

Yea it's deceptive, we put it in with out the body so it made it easy to get parrallel, perfectly on a plane
Hoppy

[Hoppy11]

Are the two shafts (gearbox and transfer) completely parrallel?

They don't look it from the photo, but photos can be deceptive.

Yea it's deceptive, we put it in with out the body so it made it easy to get parrallel, perfectly on a plane
Hoppy

[bazooked]

have ya tried a double cardan in there? might solve all ur probs. if not go to verriers and speak to craig, hey have all the latest gear for testing driveline angles, and he would be the most knowlegable in the buisness.

[rvh96]

you are running to much angle on those unis for a shaft that short you will have to drop the whole transfer case down to reduce the angles down to around 1 degre each end

[frp88]

can i ask a stupid question why are you running that set up i thought that a turbo 700 has the ability to mate to a transfer?

[Shadow]

you are running to much angle on those unis for a shaft that short you will have to drop the whole transfer case down to reduce the angles down to around 1 degre each end

why does it matter how long the shaft is?

[Hoppy11]

can i ask a stupid question why are you running that set up i thought that a turbo 700 has the ability to mate to a transfer?

I'm running this set up cause the Nissan came with this transfercase (T100) and it cost about $140 to change the spine on the original short shaft, the cost of an adapter for the Turbo 700 to an MQ T130 transfer (non divorsed) was about $900, cause no-one makes an adaptor for the Turbo 700 for use in an MQ/MK Patrol.

[Hoppy11]

you are running to much angle on those unis for a shaft that short you will have to drop the whole transfer case down to reduce the angles down to around 1 degre each end

I am no longer running to much angle on the uni's, cause the transfer has been lifted to "even out the angle"
The truck runs hard at the moment with no vibrations, it was a matter of "shimming" the transfer height to eliminate the vibration, it just seemed very strange that the vibration came back with out any visible sign of anything moving and by playing around and removing a 20mm spacer (seemed like alot at the time) solved the problem, I still run the 10mm spacer.

[Hoppy11]

In the below pics you can see the original L28 and 4 cog box, the small shaft is level, the 2nd pic of the V6 and T700 shows the auto being a bit higher and closer, motor and box could not be lowered, clearance issues with the sump and the front shaft would fowl on the corner of the auto.

[Hoppy11]

We have another hummer on the go the box is at the same height as mine but the motor is more forward cause it on a diesel Chassis and the chssis engine mounts are more forward so the small shaft is longer, reducing the angle, this one does not seem to vibrate.
Hoppy

[Hoppy11]

have ya tried a double cardan in there? might solve all ur probs. if not go to verriers and speak to craig, hey have all the latest gear for testing driveline angles, and he would be the most knowlegable in the buisness.

I had a "shaft" guy look at this, he seemed to think that a double cardin would not help, I have a friend in perth who is running a double cardin, his has the worse vibration ever, made mine seem like Mud tyre vibration, here is a pic of his
Hoppy

[rvh96]

thats not a double carden it doesnt have a centreing pin and bearing it is a standard nissan L28 jack shaft and yes it would be vibrating a shaft that short will need to run almost dead straight the way it is now it will be trying to walk the transfer case out of the truck.

[BowTieGQ]

He said shaft guy, he he he. Sorry, but I'm no help.

[38zook]

The slipjoints on a t700 have got to be running 100% strait other wise it will feel like you have a tailshaft wanting to break through the floor and sit next to you , think commodore geometry, it is totally different to rear shaft geometry , that is to the diff because different angle parrameters are needed

[Hoppy11]

At the moment there is absolutly no vibration, it seems the angle of the shaft is the only thing that will cause vibration so if it comes back I will just have to play around with the spacers that I have, I have a few now ranging from 5mm through to 20mm, I just dont know waht made it come back the other day
Hoppy

[Hoppy11]

thats not a double carden it doesnt have a centreing pin and bearing it is a standard nissan L28 jack shaft and yes it would be vibrating a shaft that short will need to run almost dead straight the way it is now it will be trying to walk the transfer case out of the truck.

Sorry, the Nissan manual call it a double Cardin??
Hoppy

[J Top]

I dont think it will work with out the 3rd UJ, it's just 2 UJ's back to back

[RUFF]

That mount you made to adapt the Holden gearbox mount to the MQ crossmember is very weak in those pics and would be bending up and down. This would also explain why removing the 20mm spacer fixed the problem this time and adding the 10mm one fixed it last time.

[Hoppy11]

That mount you made to adapt the Holden gearbox mount to the MQ crossmember is very weak in those pics and would be bending up and down. This would also explain why removing the 20mm spacer fixed the problem this time and adding the 10mm one fixed it last time.

Maybe, but it seems very strong, it does not seem to have movement in it. It is a Z bracket, the guy's that bent it up said it would not need a gusset, maybe it does, but if it flexed it would put the flanges out of paralell, and spacing the Transfer case would not make the fanges paralell it only levels out the shaft????

the vibration has not come back.
Hoppy

[Hoppy11]

Well sort of a Z bracket (it's more like a "walk like an Egyption" bracket. Work that out, no i'm not on drugs
Hoppy

[Hoppy11]

OK, walk like an egyptian.


an atempt at humuor
Hoppy
another thread on MK divorsede transfers shafts

http://www.4wdmonthly.com.au/forum/show ... 736&page=4

he sorts it on page 6
http://www.4wdmonthly.com.au/forum/show ... 736&page=6

this could be the go
Hoppy