Rich-300tdi
New Member
This is a guide for when diff lock wont engage due to little use and is seized and the hammer methods (which could end up bending linkage rods) dont work. The guide covers if its a seized linkage rod or box seizure.
After trying about 3 times to un jam my diff lock i finally did it yesterday, the reason im posting this is i used guides off here and elsewhere and it wasnt the same reason why mine wouldnt work so just thought it may help someone..
I have a t reg 300 tdi
Tools needed:
phillips screw driver
flat head screw driver
pop rivets/ rivnuts (if drilling out pop rivets)
drill (if drilling out pop rivets)
sharp knife (if not drilling out rivets)
Silicone sealer or similar (if not drilling out rivets)
grease
penetrating fluid
8mm spanner
10mm socket
13mm ratchet
torch
blow torch -box seized
vice
emery cloth or similar-box seized
possibly new 'O' rings (although i didn't)-box seized
Big and small set of moll grips
impact screw driver-box seized
trolley jack
wheel chocks
hammer-box seized
goggles
gloves
You are responsible for your safety and this is only a guide to how i did it, when hammering, spraying, or using a blow torch.. goggles, welding gloves, welding mask should be worn, when jacking the vehicle wheel chocks should be used and done on a flat surface, think about the job you are doing and what could potentially happen as it usually does happen! Work safe and stay safe.
1.Firstly chock your wheels as at times your handbrake wont be on! Right, first of all i took out the centre console, 5 screws in total i believe. 2 in cubby box, 2 at the front of the high low lever and one sneaky one near the cigarette lighter. Don't forget to un plug the lighter plug on the back and same with the bulb. To pass the console over the hand brake you need to undo the clip facing the drivers door, it should be like a cir-clip and just ease off with flat bladed screw driver. With a bit of manoeuvring the console should now pass over the hand brake with the lever in the vertical position and slide the console towards the back seats.
2. Remove the foam insulating around the gear knobs, under this you should see a rubber membrane which has pop rivets around the side, also there should be a black metal ring around the main gear lever with 4 screws holding it in. This is where you can either drill out the rivets Preferred method! or cut neatly from in front of diff lock lever down the driver side of the tunnel and along towards the passenger door, this should make it as a flap, i pulled it over both levers and with a small set of moll grips pegged it to the tunnel to keep it out of the way. Remove the screws in the metal ring and be careful as on the underside of the membrane there is another metal ring which will be loose as the screws go through both and into the bodywork.
3. Now the diff lock lever mechanism should be visible. You should see a bar coming out of the top box towards the driver side of the tunnel, a collar over it which is splined on the inside and a 8mm nut keeping this tight- this is the high/low gear selector. through the end of the bar there should be a linkage rod attached either with a nut and bolt and washers or a snap-pin type fitting, this rod should then go to a pivot bolt about 3 inches further down then down to a U shaped bit of metal which is hooked to a small arm with a 13mm nut on top of it, this is your diff lock selector. Some peoples diff lock issues can be solved here, remove the top nut and bolt. snap pin which attaches the vertical rod to the horizontal bar coming out of the high/low diff lock box.. spray some penetrating fluid onto the 13mm nut, the linkage rods at the joints and over the pivot bolt near the top. You can from above attach a 13mm ratchet to the diff lock selector and it should move into and out of diff lock when doing this, the light should illuminate on the dash providing linkage rods aren't bent. with this part moving freely-which it normally is anyway make sure the U shaped metal hook is freely moving,(can be easier at this point to do from underneath the vehicle) the pivot towards the top is usually the problem area iirc, make sure this moves left to right nice and easily, lots of penetrating fluid here.. once this is freed up go back inside the vehicle, reattach the top linkage bolt and see if diff lock now engages.. MINE DIDN'T!....
4. Inside the car take off the 4 8mm bolts which hold a gold coloured plate over the transfer box, when trying to push the lever towards diff lock, the steel bar which the linkage rod is attached to SHOULD move left to right, the bar goes through the transfer box and should move freely left to right. If this bar isn't moving take off the next for bolts around the casing,-the rear bolts are longer than the fronts.. undo the diff lock linkage rod just from the top bolt AND remove the 8mm nut which holds on the splined collar for the high low selector, remove the transfer box completely.
5. In your hand you should now have the box with the diff lock/ high low lever attached to it and the steel bar and splined piece exposed at one end.. look at the left side of this and you should see a oval metal plate with 2 Phillips bolts in it, and the other end of the steel rod just inset from the outer plate.. This is where its jammed. Using the impact driver undo the Phillips screws whilst clamping the box safely in the vice, then the plate will probably be well stuck too.. i clamped the over plate with a big set of moll grips and twisted right and left, for me this didn't work and had to apply some heat from a blow torch.. we are trying to separate the plate from the steel bar, not remove all the insides as at this point you will notice the insides all move as one left to right and we don't want that.. Eventually when the metal plate is free from the bar remove the external O ring on the shaft of the bar and the internal O ring of the aluminium plate, emery cloth the internal piece and the steel bar as this needs to slide through the internal piece. good clean up, pack the housing with grease, replace or clean up O rings and re fit and re assemble.. the lever should now move easily both ways and the bar should pass through the casing easily on both sides..
6. Place the box where it goes and run in the bolts to hold it in place making sure you slide the splined collar back onto the splines before tightening the bolts up. Now, depending where you left the high low box position your lever where you think it should be, once happy make sure the splined collar covers all the splines nicely as in make sure its on all the way, then nip up the 8mm bolt and make sure the lever position lets it engage into high low and neutral. attach diff lock linkage bar to the steel slider bar, check that diff lock light illuminates, if it doesn't don't worry as it could be just the system that needs 'unwinding' a little, you should be able to see the linkage rods physically making it engage the diff lock. To see if it is engaged jack up one wheel only and see if it moves with diff lock on, if its working it SHOULDN'T move.
7. To finish the job its just a case of re building up what you earlier took apart..
8. Engage diff lock once a week to keep it running freely!
Hope this helps!
After trying about 3 times to un jam my diff lock i finally did it yesterday, the reason im posting this is i used guides off here and elsewhere and it wasnt the same reason why mine wouldnt work so just thought it may help someone..
I have a t reg 300 tdi
Tools needed:
phillips screw driver
flat head screw driver
pop rivets/ rivnuts (if drilling out pop rivets)
drill (if drilling out pop rivets)
sharp knife (if not drilling out rivets)
Silicone sealer or similar (if not drilling out rivets)
grease
penetrating fluid
8mm spanner
10mm socket
13mm ratchet
torch
blow torch -box seized
vice
emery cloth or similar-box seized
possibly new 'O' rings (although i didn't)-box seized
Big and small set of moll grips
impact screw driver-box seized
trolley jack
wheel chocks
hammer-box seized
goggles
gloves
You are responsible for your safety and this is only a guide to how i did it, when hammering, spraying, or using a blow torch.. goggles, welding gloves, welding mask should be worn, when jacking the vehicle wheel chocks should be used and done on a flat surface, think about the job you are doing and what could potentially happen as it usually does happen! Work safe and stay safe.
1.Firstly chock your wheels as at times your handbrake wont be on! Right, first of all i took out the centre console, 5 screws in total i believe. 2 in cubby box, 2 at the front of the high low lever and one sneaky one near the cigarette lighter. Don't forget to un plug the lighter plug on the back and same with the bulb. To pass the console over the hand brake you need to undo the clip facing the drivers door, it should be like a cir-clip and just ease off with flat bladed screw driver. With a bit of manoeuvring the console should now pass over the hand brake with the lever in the vertical position and slide the console towards the back seats.
2. Remove the foam insulating around the gear knobs, under this you should see a rubber membrane which has pop rivets around the side, also there should be a black metal ring around the main gear lever with 4 screws holding it in. This is where you can either drill out the rivets Preferred method! or cut neatly from in front of diff lock lever down the driver side of the tunnel and along towards the passenger door, this should make it as a flap, i pulled it over both levers and with a small set of moll grips pegged it to the tunnel to keep it out of the way. Remove the screws in the metal ring and be careful as on the underside of the membrane there is another metal ring which will be loose as the screws go through both and into the bodywork.
3. Now the diff lock lever mechanism should be visible. You should see a bar coming out of the top box towards the driver side of the tunnel, a collar over it which is splined on the inside and a 8mm nut keeping this tight- this is the high/low gear selector. through the end of the bar there should be a linkage rod attached either with a nut and bolt and washers or a snap-pin type fitting, this rod should then go to a pivot bolt about 3 inches further down then down to a U shaped bit of metal which is hooked to a small arm with a 13mm nut on top of it, this is your diff lock selector. Some peoples diff lock issues can be solved here, remove the top nut and bolt. snap pin which attaches the vertical rod to the horizontal bar coming out of the high/low diff lock box.. spray some penetrating fluid onto the 13mm nut, the linkage rods at the joints and over the pivot bolt near the top. You can from above attach a 13mm ratchet to the diff lock selector and it should move into and out of diff lock when doing this, the light should illuminate on the dash providing linkage rods aren't bent. with this part moving freely-which it normally is anyway make sure the U shaped metal hook is freely moving,(can be easier at this point to do from underneath the vehicle) the pivot towards the top is usually the problem area iirc, make sure this moves left to right nice and easily, lots of penetrating fluid here.. once this is freed up go back inside the vehicle, reattach the top linkage bolt and see if diff lock now engages.. MINE DIDN'T!....
4. Inside the car take off the 4 8mm bolts which hold a gold coloured plate over the transfer box, when trying to push the lever towards diff lock, the steel bar which the linkage rod is attached to SHOULD move left to right, the bar goes through the transfer box and should move freely left to right. If this bar isn't moving take off the next for bolts around the casing,-the rear bolts are longer than the fronts.. undo the diff lock linkage rod just from the top bolt AND remove the 8mm nut which holds on the splined collar for the high low selector, remove the transfer box completely.
5. In your hand you should now have the box with the diff lock/ high low lever attached to it and the steel bar and splined piece exposed at one end.. look at the left side of this and you should see a oval metal plate with 2 Phillips bolts in it, and the other end of the steel rod just inset from the outer plate.. This is where its jammed. Using the impact driver undo the Phillips screws whilst clamping the box safely in the vice, then the plate will probably be well stuck too.. i clamped the over plate with a big set of moll grips and twisted right and left, for me this didn't work and had to apply some heat from a blow torch.. we are trying to separate the plate from the steel bar, not remove all the insides as at this point you will notice the insides all move as one left to right and we don't want that.. Eventually when the metal plate is free from the bar remove the external O ring on the shaft of the bar and the internal O ring of the aluminium plate, emery cloth the internal piece and the steel bar as this needs to slide through the internal piece. good clean up, pack the housing with grease, replace or clean up O rings and re fit and re assemble.. the lever should now move easily both ways and the bar should pass through the casing easily on both sides..
6. Place the box where it goes and run in the bolts to hold it in place making sure you slide the splined collar back onto the splines before tightening the bolts up. Now, depending where you left the high low box position your lever where you think it should be, once happy make sure the splined collar covers all the splines nicely as in make sure its on all the way, then nip up the 8mm bolt and make sure the lever position lets it engage into high low and neutral. attach diff lock linkage bar to the steel slider bar, check that diff lock light illuminates, if it doesn't don't worry as it could be just the system that needs 'unwinding' a little, you should be able to see the linkage rods physically making it engage the diff lock. To see if it is engaged jack up one wheel only and see if it moves with diff lock on, if its working it SHOULDN'T move.
7. To finish the job its just a case of re building up what you earlier took apart..
8. Engage diff lock once a week to keep it running freely!
Hope this helps!
Last edited:
