Series 3 Play In Transfer Box Main Shaft.

I have a small amount of play in the main shaft of the transfer box, if I grab the rear prop just near the hand brake drum I can feel some movement and you can just about see the drum moving relative to the backing plate so I guess that I have wear in the taper roller bearings that support the shaft. I did think about removing a shim from the speedo drive housing but though that could only be a temporary fix and that the bearing must be on borrowed time.

Rather than mess around with the fitted transfer box I brought a second hand one and though I would rebuild that instead. Anyway this replacement box also had a small amount of play in the shaft. I started to strip it last night and it soon became apparent that this box was probably beyond repair, both the helical cut gears are badly pitted. I took the main shaft out and surprisingly the taper rollers were not to bad so I was a little confused as to where the play in the shaft was coming from. One of the inner taper roller races butts up against a circlip, it looks like most of the wear is on this clip and this is allowing the bearing to slide further along the shaft but there is also some wear on the back of the bearing. I measured the wear on the clip and the back of the bearing and it adds up to about 5 thou, the thinnest shim for pre loading the taper rollers is 3 thou.

I'm guessing this is what is wrong with the fitted box. Is there anything I can do to stop this happening again, would it be wise to loctite this bearing onto the shaft?

Not practical to loctite the bearing onto the shaft the bearing and circlip would normally be rotating at the same speed so should not wear, maybe it has been run in the past with two much freeplay. Commonest failure is the larger circlip failing that holds the bearing outer as people have put too much preload on the taper bearing.
I would dismantle the current transfer case hand brake and speedo housing in place on the vehicle and remove shims to get correct loading.
Got a minor oil leak on mine at brake drum at the moment and will be checking the same play shortly.

Gearbox and overdrive are being replace so the transfer box is going to get a rebuild while its all out. This gives me the opportunity to loctite into position. The transfer box looks to be pretty robust. If I can prevent this fretting damage I'm hoping I never need to look inside again.

Citizen Kane said:

Gearbox and overdrive are being replace so the transfer box is going to get a rebuild while its all out. This gives me the opportunity to loctite into position. The transfer box looks to be pretty robust. If I can prevent this fretting damage I'm hoping I never need to look inside again.

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just get a new circlip and get preload right m,you have to be careful if you buy new bearings some have too much of a chamfer were that circlip butts against,they will just jam the gear when preloads added