I am thinking of purchasing a 99' Blazer, 4x4 V6 with 134,000 miles, automatic transmission, for only $500. There is a small leak from the transmission pan and the AC does not work. My main concern is the transmission blowing up on me 10,000 miles later. How many miles do they usually last? Are there any other problems I should be aware of?

 

If it has never been used for towing, then the transmission is more likely to still be ok. I mention this because I burned up a perfectly fine transmission on my 99 (at about 130,000 miles) by towing my boat while using overdrive during which it got too hot. (Don't tow with overdrive!) So if it doesn't have a receiver mounted on it, then that is one good clue. A quality rebuild including the addition of upgraded components and an extra transmission oil cooler cost me $2,700.

If the fluid was allowed to get low then other damage could have occurred to the transmission. So if you can figure out if it was ever run dry, that should help you guess if the transmission is long for this world or not. Ideally, the transmission fluid will have been regularly serviced. If it has, then it could go until 200,000 miles I would think.

For the AC system, a DIY replacement only cost me about $325. I have a thread on doing this in my build thread if you are interested in doing it yourself.

Front suspension components are items that wear a lot and will likely need replacing; ball joints, and the idler arm are the most common to need replacing.

The under hood vacuum hoses have likely rotted at 20 years old. This affects both the HVAC and engagement of the front axle for 4wd. Depending on the transfer case, the regular "3-button" or the Auto 4wd "4-button", the loss of vacuum can affect the transfer case too (for the 3 button one). This is the perhaps one of the easiest and least expensive fixes with the largest "bang for you buck."

The 99 engines were assembled with the not so great lower-intake-manifold (LIM) gaskets can have been known to fail catastrophically dumping coolant into the engine oil system. This can ruin the engine. Replacing these with upgraded gaskets is not an uncommon repair. It is very doable by the home mechanics but it does take time as there is a lot of stuff to remove to get to them. They can fail with little warning. When I learned of this, I replacement immediately because I knew I was going to keep my Blazer for a while. Look for any hint of coolant in the engine oil.

The 4.3Ls with the remote oil filter were notorious for the oil lines between the filter and the engine leaking. I have never heard of these bursting with a catastrophic loss of oil and are more of an annoyance. But on my '92, I did have the o-ring for the adapter for these hoses to the block break and I had lots of oil loss. I was able to drive it but I had to carry extra quarts of oil even for a 20 mile drive until I got it to a mechanic.

If you are thinking this is a truck you might keep for while, even if you have to put $1000 into it (or perhaps even more), getting it for $500 might be well worth it as there is no other body-on-fame SUV of this size.

 

My trans is original... has about 350xxx km on it.

edit: forgot to mention it's a 99 4 door 4x4 aswell

 

There you go. A properly maintained transmission should be able to go at least 215,000 miles.

 

I'm coming up on 158xxx on mine, transmission is fine but I'm replacing the transfer case within the month.

 

I did do a transmission service at the 250xxx km mark.

 

I think I last serviced my transmission around 150xxx. I'd have to look over my receipts. I know it was last November before I moved out to New Mexico and the truck made the trip perfectly. I recently had all my fluids redone and my chassis lubed and there was metal shavings in the transfer case fluid.