Patrol Rear Diff Problems

[makeitfit]

Never had that issue with mine but have heard that the diff lock actuator is a bit suspect.
No idea why it would shoot off to one side other than local road conditions like camber or wetness ?

 

[solarman216]

After a bit of rooting around discovered that it is routed through the Glow plug controller, as I do not have an ECU on mine the Glow plug unit handles the plug timings and related parameters like coolant temperature, current battery voltage, how long it has it has been running over a certain revs, etc it also handles the tachometer, and now discovered the diff lock in as much as it will not allow diff lock above a certain speed, now this little box of tricks sits down by the throttle pedal and has been wet a couple of times, certainly the Tacho plays up regularly, for the moment I have disconnected the "lock" vac pipe leaving the "unlock" pipe attached, if this cures the problem then a mod will be required to simply connect the switch direct to the two vac control valves so by passing the "control unit" which I feel is playing about, glow plugs will go the same way via a simple timing unit to keep them on for a few mins after starting, Rick

 

[makeitfit]

Have you got a pic of that unit please Ric

 

[solarman216]

No but get one tomorrow, Rick

 

[solarman216]

Location of unit

 

[solarman216]

Detail plate. Rick

 

[macabethiel]

All that diff strip down - its not the diff itself.

Sorry no pics but all back together and at the mo can only say the on lock vac is stronger than the off lock vac so poss a leaky pipe, it still does not fully explain why it only ever pulled to the right, never once to the left, maybe something to do with the lock not fully engaging but just ratcheting, which is the noise I heard, more investigation yet to come, not heard a peep from other Patrol owners so assume not a common problem, anyway real glad I have the experience of stripping it as I now know what a solid bit of kit this rear diff is, Rick

I would be well hacked off after all that work for it not to be the diff.
Were there any issues such as diff bearing preload on the rebuild or is it okay?
I guess its far more likely to be a loss of vacuum on old pipework or even the control unit.

I assume you have ruled out a sticking handbrake cable or brake caliper / drum.

Reminded me of when I took the gearbox out of my brothers Austin 1100 -twice -for jumping out of gear. Turned our to be lower subframe mountings had ripped out part of the front floor!!

 

[solarman216]

No problem with bearing pre-load, one cap I did not disturb the other just wound it up to the marks I made, however the pinion was another matter upon looking at the inner bearing when turning the pinion the rollers were not rotating, so stripped that out to check it over, conclusion was that there was insufficient pre-load, the adjustment here is with shims, one 5 mm the other 2.2 mm so took 0.2 mm off the thicker one, assembles it up without the oil seal and now got the prescribed loading, pulled it apart and re fitted the oil seal so bob's your uncle all hunky dorry, as an add, removing the lock vac hose did not cure it, as the control system is clearly the culprit whilst not being able to lock the diff it was removing the unlock vac so the vac chamber is free to move which it did to the tune of nasty ratcheting sounds, cured it now though, put permanent vac on the unlock chamber, Rick

 

[makeitfit]

Detail plate. Rick

Thanks Rick, I'll go and get mine out for a check over.