80 series centre diff lock

Oil sludge cold? Creek crossings? Synthetic diff oil say 75W 90 front 75W 140 rear. Just sounds like contamination/rust. Just a thought....silverback

Rob,

When was the last time the gear box oil was changed?

The 80 Series gear box had very light gear oil in it. If the oil is too heavy or too old this might be the problem.

Once the gear oil is warm everything works fine, I would check the oil first.

Wayne

Wasn't there a problem in this model where oil migrated into or out of the tranfer case from the gearbox? Someone else will be able to clarify this, but could that be the problem?
Cheers
Gerry

are you sure that the centre diff isnt actually locking and that its not just a faulty centre diff indicator light.

personally i dont think the grade of oil makes any difference (provided its good clean oill)
I have always run 85/140 in diffs, gearbox and transfer case in my 92 gxl and it has never been touched with over 425,000 on the clock.
I also have a 97 model with the vicous coupling and I admit I only run 85/90 in that transfer case even though I still use 85/140 in diffs and g box.

hope you work it
cheers
howard