99 nl 3.5 slips in 4h

[Ian Sharpe]

The slipping??

try to get it into Low or 4Hc, if you have drive then its a pretty good guess that the front right hand side axle is not engaging, the drive is taking the easiest route & that will be the centre diff spinning its head off & you loosing power.

[twsawyer]

Thats what it sounds like, can the vacuum solenoids be the cause of this?

[Ian Sharpe]

I;m not 100% sure on that, best bet is to slip the rubber boot back & see if the shaft is engaging. The inner shaft could have also slipped its circlip (which happened to me)

[Pauly Faulkner]

No, not in your case.
Since you have vacuum on blue constanly and nothing on yellow constantly you should be permanently engaged.

You need to sort out the mechanical side first before looking into the idiot light issue. With both vacuum hoses off you should still have engagement as it's spring loaded to the defaukt position of engaged, the blue dot solenoid(engage) is technically not needed but is there to speed up and assist the engagement when car is moving as it can cause grinding if the engageme t moves to slow (evident by switching car off and rolling along when in 2wd the diff goes to engage but doesn't do it wuick enough and it grinds).

[twsawyer]

Hi all after playing with the solenoids and hoses etc i have
Fixed all the flashing light issues all i am left with is the problem of
It slipping in 4h, works perfectly in all other modes!

Where to from here?

[Ian Sharpe]

Hi all after playing with the solenoids and hoses etc i have
Fixed all the flashing light issues all i am left with is the problem of
It slipping in 4h, works perfectly in all other modes!

Where to from here?

yep its still the front axle not engaging.

[Pauly Faulkner]

+1 Ian

Like I was saying twsawyer, you need to check the mechanical side as you have a wierd issue. Especially seeing as your lights all work but still have what appears to be a disengaged diff.

Do the manually turning wheel trick I said and check passenger side also, it's almost as if the hubs aren't locked in but you say you don't have hubs

[twsawyer]

Sounds good ill do those mechanical checks when i get a chance,
Question out curiosity why does it drive fine in modes with centre lock engaged
But not normal 4h?

[Pauly Faulkner]

Just an fyi, in 2wd the rear tailshaft is locked and front unlocked in the centre diff(centre diff is the transfer case). In 4hi both are unlocked and run off a viscous hub (basically makes it an lsd) so when the front diff isn't engaged or you have freewheeling hubs set to free position it becomes the path of least resistance and gets all the engine power, kinda like when one wheel lifts on a lsd rear diff and the wheel in the air gets all the power while wheel on the grounf only gets a little.

In locked centre (4hLc/4lLc) both front and rear are locked together so there's no slip.

If front is somehow disengaged whether it be diff or hubs, the car will only dribe/accelerate per normal in 2wd or locked centre 4wd modes. In 4hi it will just slip and go nowhere in a hurry.

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