RPegram

I agree with Fast55 on the transmission. You can leave that alone right now. I would address the coolant leak as soon as possible. The timing chain you can check by moving harmonic balancer back and forth and check for play. With those miles there will be some. If finances allow, then change timing chain. If finances don't allow and chain breaks in future, it won't cause catastrophic damage. Your engine is not timing sensitive, so no valves will make contact with pistons. The two jobs are pretty independent of each other, so it would not be like doing the same job twice. As far as compression, I would do this if you are experiencing problems with weak cylinder, misfire you can't diagnose or excessive oil burn. If compression comes in low on one or more cylinders, then you are looking at engine replacement/rebuild. If money is tight, prioritize and take care of problems that can get worse very quick and cause other damage when they do, then work your way down list as money allows.

Imuz me

Hey guys new here. Poking around for awile though. My 99 Tahoe 125K miles. begin to slowly leak water out the intake manifold last year. (I had the small drips under the driver side off the bottom of the tranny) it has progressvly been getting worse. after much research it seems this is a VERY common problem on GM trucks with these motors. When the weather gets warmer, I will tear the top off intake manifold etc. and change the intake mainfold gasked (had the same problem on my 94 CK a number of years ago/intake gasket fixed the issue) For now I did the complete flush out of the coolent system and then did the Bars Leak "head gasket repair". I followed the instructions to a T. after letting it sit and cure for about 24 hours I again did a complete flush and refilled the system with about 50/50 dex cool per manual. It seems to have helped for now. No leaking. I'll report back and let you know how long his lasts. If your looking for a good tutorial on changing out the gasket. I found this. http://www.market-place.com/intake/intake.htm

FYI, for the record: I never had any overheating, just noticed coolent Loss. No milky oil or water in oil and no excessive water out the tailpipe etc.. Of coarse I would not lose coolent once the engine was warm, as the block, heads, intake and gaskets expanded etc...