1987 110 prop shaft spinning, wheels not turning

[Thayne]

Seeking wisdom on what is wrong and how it works...

After sitting for nearly 20 years, I am trying to get my 1987 110 County 2.5 Petrol (LT77?) running.

With the vehicle on jacks, I have tried to get it in gear.  The front prop shaft is spinning fine, and the Universal Joints seem to be doing their job, with no play.

The front wheels, however, are not turning.  My first thought was that it should always be engaged, so I should take apart the diff to see if there is something obviously broken.

But then, I thought that the center differential must be communicating somehow mechanically to the front diff to engage diff lock.

I have not figured out how they are communicating, and/or if there is something simple to get the wheels to engage with the prop shaft.

I have not found any good videos or explanations of this particular aspect.

Any thoughts? or can you point me to some good resources?

[JohnnoK]

Does it have free-wheeling hubs fitted?

Something like this...

If so, they need to be engaged for the wheels to drive, but if they've been unused for a long time they can get sticky and uncooperative.

If not fitted, the diff is possibly in need of repair.

[Stellaghost]

A snapped half shaft would also stop drive as the diff turns with the path of least resistance.

I would check diff and shafts

regards Stephen

[FridgeFreezer]

On 6/22/2024 at 7:18 PM, Thayne said:

But then, I thought that the center differential must be communicating somehow mechanically to the front diff to engage diff lock.

There are no cross-axle diff locks as standard on these, only a diff & locking dog clutch inside the transfer case.

If the propshaft is spinning, at least one wheel should be turning - as Stellagost says, a snapped shaft in the axle would let all the power spin out to nowhere.

if you've got it jacked up, hold one wheel and try to turn the other - the propshaft should turn. If it doesn't, suspect the driveshaft or CV on that side.

Pictures also help - we might spot something that you might not be familiar with.

[steve b]

Another common fail point is the drive flange splines tearing out - an easy check , pop the rubber end caps off the drive flanges and repeat your original test to see if the drive shaft end spins. 

OEM flanges are my choice for replacement , most of the so-called hardened upgrade options are soft as a soft thing....

Steve

[FridgeFreezer]

3 hours ago, steve b said:

OEM flanges are my choice for replacement , most of the so-called hardened upgrade options are soft as a soft thing....

I fitted Terrafirma ones as they were 15 quid a pop and have the screw-on end caps since the OE rubber ones kept popping off. Time will tell how well they last - they've been on for maybe 5-10k so far.

[steve b]

The latest pair of those I replaced a couple of months ago had done about 25k miles according to the owner - 99% road use.

If I can find one in the scrap I'll take a pic of it

Steve

[Bowie69]

I fitted Ashcroft probably 5K ago, will have them off at the weekend so will give an update on their condition.