I now have 127,000 miles on my 95 T-100. I was thinking about having the valves adjusted since I am the second owner and I doubt they were touched before. What kind of price should I expect to pay to have them adjusted? Is it difficult to do myself? At 127K miles, do you think the valve adjustment will make a difference in power?

It wouldn't be a bad idea to have a look at valve clearances with this mileage (believe Toyota recommends 60K mile intervals; that was the recommendation on my 1993 3.0 and I'm guessing you have the 3.4).

My only concern is that there aren't many techs (in my experience) that have the ability or inclination to do a proper job of it. It is important to be fastidious (even anal-retentive) to do this job right. You could easily wind up spending at least a couple of hundred dollars and having a pickup that doesn't run as well due to incorrect clearances (you realize that these are shim-adjusted valves, right?)

If you are mechanically-inclined and have access to the factory procedure, you should be capable of at least checking the clearances yourself. Basically you need to remove enough stuff (I'm not familiar with the 3.4; I only know it's a 4-valve head rather than a 2-valve) to be able to remove the valve covers, then turn the engine using a breaker bar on the crank pulley so that you can check clearances at certain points along the crank rotation. Toyota specifies a range (say 0.10 to 0.15 mm) for each clearance, so you have some leeway. If clearances are out of spec, you must remove the shim for the valve in question (again, not being familiar with that engine, you either need a special valve depresser tool or must remove the camshaft) and swap it for the shim that provides a clearance within the proper range.

In my experience with shim-type valve adjusters, the engines usually "settle in" after the first adjustment and may not need another adjustment for the life of the engine. But it sounds like this one has never been touched.

I brought my truck in last week and had the valves checked and adjusted. My T100 has the 3.4 with 122,000 miles on it. The cost was $276 for labor and $24 for shims. When I asked about purchasing a shim kit they told me that the kit sells for $30. The valves are a little quieter after the valve adjustment. I haven't noticed any increase in power, it is more preventive maintenance so the tolerances stay in spec and the engine dosen't burn a valve. I read through old posts here before having the work done. It seems that at least one special tool is needed to access the shims and based on the time involved and my level of experience, I decided to have the dealer do the work.

Its a lot of work and costs accordingly, but it can be done yourself if you're mechanically inclined and have the FSM. You can do it w/o the special tool, but the tool makes the job a lot easier (costs about $40). Shims are a few bucks a piece ($9?) but you can usually get away with swapping a few around instead of buying all new ones. I ended up adjusting about 6 valves (all exhaust valves), but only bought 2 shims since I was able to swap the others to get them into spec. The dealers usually stock them and there are quite a few different sizes, so I don't know what would come in a $30 "shim kit." I just did the measurements, bought what I thought I'd need, and returned what I didn't.

I just tried to schedule the valve adjustment with the dealer. The service rep told me that unless the valves seem to be making noise they don't adjust them as routine maintenance. Does this make sense? Someone mentioned that the adjustment should be done at 60K miles intervals. That seems like routine maintenance to me. I have had excellent service from this dealership in the past so I do tend to trust them.

the techs do not want to do it because it is a headache, and they will most likely not be able to finish in half the time allowed by mitchells for the work. they want the gravy, easy stuff to be able to bill 20 hours for a job that they can do in 10. tell him that you do not care what he recommends, btu that you want your valves checked. you are looking ar some $$$ though. there are some parts to put it all back together (gaskets, seals, etc) and the shims are $9 each. i plan to do mine soon and already have all the gaskets and such. i will play musical chairs with teh shims and only buy what i need.