Foot Brake and Rear Drive

[idawson]

Hi,

I acquired a partially built 1988 defender 90 and have been working on its problems. I've a weird problem that if the Diff is locked and if I engage the drive eg 1st gear the rear prop doesnt turn, but if i press the foot brake with lightly, the rear prop starts to turn???

can anyone offer any insight into whats going on???

Thanks

[landroversforever]

Has the Difflock linkage been connected up/operated correctly? Sounds like it's open and something is broken?

[Flash17]

Ok that's weird.

for give me for asking but is the diff definitely in the locked position? or are you relying on the position of the diff lock lever to confirm this?

I'm fairly simple and go for checking the easy stuff first.

Am I right to assume you have the vehicle off the ground with the four wheels/hubs free to spin?

If I were doing this I would:

drop front and rear props off the transfer case.

with the engine shut down

put the main gear box in gear

ensure the transfer box is not in neutral

place the dif lock in

release the handbrake

attempt to rotate one transfer box output flange by hand (it shouldn't rotate)

now take the diff lock out

try and rotate one of the transfer case output flanges by hand (it should rotate freely and the other flange should rotate in the opposite direction) if I'm wrong can someone correct me quick

if the above is correct its not the diff or its operating mechanism and I haven't a clue.

if the opposite occurs then I have no idea why, but you diff locked and open positions are swapped maybe because of the operating mechanism. It may seem strange but the high and low on my 110 are the opposite way round to what the top of the transfer gear knob says I just live with it and cant be arsed to try and change it.

if the diff wont lock at all after the above test so you can always rotate by hand and the other flange rotates opposite, check for slack in the operating mechanism and if found disconnect the mechanism and try engaging and disengaging with the lever directly on top of the transfer case.

if the diff now locks you have slack/wear in the operating lever/mechanism, if it stays unlocked I'd guess you have problems deeper in your transfer case and it may be time to have a look in the tech manuals

It may get you more help if you were to identify what gearbox/engine combo you car is as people may have experience of something similar. eg lt95 (combined four speed and tx case), or lt77, lt85, r380 (five speed with a separate 230 transfer box)