Carrier bearing life span questions

[70Custom10Nut]

How long should a carrier bearing last? (on my LWB 70)
I put a new one (Timkin) in about 8,000 miles ago, and in the beginning the rubber seal had an annoying squeak at low speed.
(fast forward ten years) After sitting in storage for 5 years while I was in Europe, I noticed the squeak was gone but now the bearing clunks a lot under hard acceleration from low speeds. It worked well in the beginning, so I know I have it in there right. There is some play in the carrier itself, and the bearing seems to be "floating" inside the rubber seal. The rubber is in good shape with no cracks or holes. I guess my questions are:
1. Is this normal for them to squeak?
2. Is it normal to have the play in the unit?
3. Is it normal for them to clunk at low speed?
4. Do they wear out that quick?
The truck has not been worked very hard since I've had it so I know none of the symptoms are from abuse. Cnut