Not Able to Go in Gear unless in High Drive

Hello All

I have an old 1988, 90 pickup with a 300tdi, not sure of version of gearbox but reverse is top left.

Anyhow the problem - I've not driven this much since purchase but like a fool I didnt test everything properly. Just changed the shoes for the handbrake and while doing this realised the front prop wasn't turning when jacked and chocked. Checked the High/Low and realised its been in High range all the time. Put everything back together and no high or low selected and it wouldn't go into gear. Clutch pedal pressed and just crunching when trying to get in gear.

Put it back in High range and it went into 1st straight away. Drives through all gears no problems in High range.

Would this likely be the transfer box or a gearbox problem.

Thanks in advance.
Jason

The transfer box, which is what selects High or Low range has to be in either High or Low to get drive to the propshafts.
It is perfectly normal to have this gearbox in High for normal road use.

This is the 'transfer gearbox' and can be locked so that drive goes to both the front and rear propshaft or unlocked so that drive is transfered to the wheel with the least resistance (unwieghted).
By this I mean that if you lift one corner of the car (front, back, left or right) then unlocked this wheel will spin. Put the transfer box into 4WD (locked) and you will put drive onto both axles (front and back) and you would need to lift one wheel from each axle off the ground.

When you chocked the car and changed the handbrake pads it was perfectly normal not to see the front prop turning.

Your box will be an lt77 and the transfer box an lt 230. Better explanation needed with what wheels were jacked and which were chocked.
Does it drive in low range ? The transfer box has a neutral position between high and low. Check clutch fluid level, a low level can result in clutch not fully disengaging and gears crunching, more so the low ones.

If the transfer box is in neutral then the whole gearbox internals will turn due to friction, which may impede gears lining up, hence the crunching.
If it is ok in high, then try it in low. If it is ok then I would say don't worry.

J

Thank you all for your detailed explanations, `I will try the Low range and see if it drives and report back but thanks to you all `I now understand a lot better how the `low and High works with normal and diff lock. I did check the clutch fluid but will check again to be sure.

`I watched a video about changing the handbrake shoes which said jack the back up and chock the front wheels and then the drum should turn to be able to adjust. ```this didn’t work for me as the front wheels were stopping it turning fully so took off rear and front prop when `I took the drum apart. It still wouldn’t spin when adjusted and then put the transfer in neutral and it turned. When I started it up to have a test drive that’s when it wouldn’t go in gear as still in neutral.

`Question that arose from this - I also have a newer adventure edition defender which `i tested in neutral and it went in gear no problem, no crunching or anything. `It won’t drive in Neutral but you have explained why this is so thank you all for your kind help.

Sounds like you had it in diff lock when doing the job. Check diff lock is not stuck in lock position [ not good driving on hard surface ]
Jack any wheel up and spin it, no spin it is locked.
Also It may have been you had the main box in gear when you were trying to spin the drum. Neutral in either box would allow the drum to spin provided one wheel is off the ground and lock is out.

Stick it in high range and leave it there, it is the normal position for road use, you should never need to use low range or diff lock under normal use.
DRIVING IN DIFF LOCK WILL WIND UP YOUR TRANSMISSION , IT IS ONLY USED IF YOU ARE STUCK AND WHEELS SPINNING, BUT SHOULD BE TAKEN OUT OF DIFF LOCK WHEN MOVING AGAIN.

Diff lock should be engaged if you are driving on dodgy ground before you get stuck. There is no problem driving in lock on slippery/loose ground.
It is good to exercise the low and lock mechanism now and then to prevent seizing.

tottot said:

Diff lock should be engaged if you are driving on dodgy ground before you get stuck. There is no problem driving in lock on slippery/loose ground.
It is good to exercise the low and lock mechanism now and then to prevent seizing.

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Yes but as the owner obviously knows nothing about how his landy works so I was keeping it brief for road use. Not a good idea to be turning corners in diff lock. Agree good idea to engage it now and again on the straight briefly to keep linkages free. I have never needed to use it yet, but my TD5 90 had traction control

Fair enough Scooby, keeping it simple is often best.

I checked as you suggested in Low and all fine, I suspect the transfer was in High lock when doing the handbrake as checking again today and found the diff lock connector was unplugged so no lights on dash to confirm in High or Low. Time will tell I guess if this has caused damage but luckily I have only travelled locally since purchase and low speeds. Thank you all for your help.

Driving on hard surface in diff lock is unlikely to damage the system in the short term, but the transmission wind up does load up all components of the drive train and result in damage/failure over time. Good truck is now sorted.

ciscocoles said:

I checked as you suggested in Low and all fine, I suspect the transfer was in High lock when doing the handbrake as checking again today and found the diff lock connector was unplugged so no lights on dash to confirm in High or Low. Time will tell I guess if this has caused damage but luckily I have only travelled locally since purchase and low speeds. Thank you all for your help.

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You won't have lights on the dash to say high or low, the selector position tells you. No different to to the gear selector, that doesn't flash up on the dash in a fender either. You should have a light for diff lock which may remain on once you come out of lock. That usually means you will need to unwind it a bit.

If the diff lock remains in [ light on ] when you move lever to the out position stop and then reverse some while holding lever in out position. Or just drive with NS wheels on the grass verge. Either way works.