P38A Stall speed monitoring gearbox fault

[Grrrrrr]

Well after weeks of waiting for parts the first steps to getting everything back together were made today.

These are the little f***ers that get loose over time:
View attachment 315219
Partnumber TYP000010, still available at Land Rover. I bought new ones as they include a wavy spring washer, which on the old bolts might have lost some springiness. Didn't want to take a chance on these. I also degreased everything and used loctite on the threads. Not prescribed by RAVE but less likely to rattle loose.


Another issue was that this parking gear together with the sensor trigger wheel doubles as an oil sprayer for the output bearing. The sprocket slides over an O-ring on the shaft, and the collar you can see on the picture above around the shaft hole slides over a piston ring type seal. This creates an oil chamber and a small hole in the sprocket allows oil to spray onto the bearing. For this reason the o-ring on the output shaft needs to be replaced, this is STC4602 which is not produced anymore, not by LR or aftermarket brands. I settled for a 25x2mm FPM o-ring which was the closest match to what I think is a 1"x5/64" O-ring.

Did you try Wych Bearings? They've always come up trumps for me.

 

[ar1g3]

Did you try Wych Bearings? They've always come up trumps for me.

I did not, but now it's too late as it's partly assembled again. But I think my solution will work, the o-ring size is within tenths of a mm of what was fitted before.

 

[Grrrrrr]

I did not, but now it's too late as it's partly assembled again. But I think my solution will work, the o-ring size is within tenths of a mm of what was fitted before.

Been there before. Everything crossed here.

 

[ar1g3]

Everything finally back together, still need to test it but first some other jobs while the car is in the garage.

Some advice for those tackling this job:
- main thing needed is 2 ways of supporting the gearbox, one static and one jack. You will need to switch them, and be able to remove the transfer box off the jack.
- prop shaft nuts are bastards, use 9/16 3/8 drive socket plus suitable extensions
- use new screws and loctite when bolting the trigger wheel to the park brake gear
- grease the flanges of the chassis crossmember when refitting, use a jack and mallet to get it in
- you don't need to remove the exhaust front pipe! Just unbolt the connection to the middle box
- I had the car on bump stops and needed to raise the chassis for fitting/removing the props as they where too long to go over the bolts on the transfer box side. Raising the car extends the prop shafts

Final advice: use a bore scope to check the bolts before ordering a new sensor.