How to tell if 4x4 is fully engaged

[BigRedNz]

Hi guys i need some help..i have a 97 3.1td mu and im not sure if the 4wd is fully engaging. I went out for a fish last night and got stuck on a small sand hill i had it in 4wl and hubs locked and i had to get pulled out.
is there a way to see if its fully engaged in 4x4?.
My hilux climbs those hills easily in 4x4 which is why im wondering if its not engaged.

Cheers Red

[geeves]

2 easy tests
First does your Mu being a 97 have shift on the fly or convential hubs. Or both??
Have a look at the front diff to see if there is an assembly on the left hand side with vac pipes going to it. This is sotf and complicates the below
First test engine off in 2wd and hubs unlocked. Reach underneath and make sure you can turn both front axles
Second test lock both hubs and repeat axle test. If either turn fix that free wheel hub
third test check front driveshaft cannot turn
Release hubs and ensure driveshaft now turns
Place in 4wd but leave hubs unlocked If it has push button 4wd this may require engine runnig
Check driveshaft cannot be turned
Report back with results

[BigRedNz]

Hi and ty for the speedy reply..i did as you said and the following occured...there is an air hose on the left hand side going into the diff.
engine off 2wd hubs unlocked..both turn freely.
2nd test hubs locked..neither turned.
3rd test put mu in 4wd high without hubs locked...both turned
4th test put truck in 4wd low without hubs locked...both turned.

repeated both these tests with truck running...same results both turn.

5th test locked hubs whilst in L4 and neither could turn..

my hubs are manual locking hubs no such luck as push buttons here..

[geeves]

third test onwards is on the driveshaft from the gearbox to the diff.
I think you are talking about a breather pipe on top of the diff I was talking about a separate assembly on the left of the actual diff bulge. This has at least 2 vacume pipes a couple of solinoids etc.
You have proved your hubs are ok. The push button I was talking about is a button on the dash instead of a lever by the gear stick

[BigRedNz]

Thank you very much for your help