I owned a 1991 LS400 for 12 years. The timing belt change interval in MY owners manual was 60,000 miles, NOT 90,000 miles. When the dealer replaced the TB he also replaced the water pump and charged for it under the extended power train warranty. I just had the TB of my 2002 LS430 changed and at almost 90,000 miles the extended power train warranty was only a memory. The dealer was not automatically going to replace the water pump but I insisted on that. Also, the dealer was not going to change the serpentine belt for the accessories! I had then do that as well. I was already paying for them to remove and install those items so it just seemed to make sense to have those other major wear items replaced for just the cost of the parts!