Complete swap or?

[marshallsmith27]

To make a long story short I have 1989 2wd GMC Sierra that belongs to my grandfather but sits at my parents. I had been traveling for work and on one of my trips my car was totaled in bad weather. I moved to Boston then and I had no need for a vehicle only my motorcycle for commuting. I am back in Alabama for the time being and I think it would be more cost effective to fix the Sierra than buy a. used vehicle. I think the truck has 220k on the odometer. it runs But hasn’t been started in a year or two. it smokes like hell and the transmission slips. It’s the v6 which I think is the 5.4(?). I am either moving to San Antonio or back to Boston soon and this truck has a long bed and the AC works. My real question is how do y’all recommend I go about fixing the truck? I’m sure I can find a transmission at a junkyard locally but engine wise. should I buy a remanufactured engine or have this one rebuilt? Cost wise I want to keep the spending low. my friend and his brother has a giant shop at their house with everything we need so the only question is how to go about like I stated above. I wish it was a v8 but I assume that would take much more wiring etc. the interior is mint and the paint is pretty new so it’s a great truck it just needs a new driveline.

 

[DonYukon]

If its the V6 you have the 4.3 . just because the engine is smoking doesn't mean that its a goner . what kind of smoke is it oil or coolant? could be a blown head gasket which if it hasn't been overheated to badly can be fixed. could be a number of things.

The transmission on the other hand what's its story? Low fluid can cause it to slip. ect... more info is needed before we tell you to just shotgun engines and transmissions at it.

 

[marshallsmith27]

Yeah sorry I should have mentioned the smoke color. it’s white. it’s pretty thick. I’m sure it needs seals. it smokes from start up and while running it doesn’t really improve. If i remember right it was bluish smoke. the transmission I am not sure. my dad drove it for maybe a year and would pull his utility trailer with it occasionally just so he wouldn’t have to keep buying gas in his 06 2500 sierra with the allison trans. terrible gas mileage with that truck for a daily.

My grandfather is the finicky type. he bought it new and no one else ever drove it until it was brought over here to get it out of the way of his small driveway. I very highly doubt he ever let the transmission fluid get low. he kept it maintained at the GMC dealership up until he bought a new truck.

If you don’t mind firing questions at me I can answer them but I cant think of anything else to add at the moment

 

[marshallsmith27]

oh and the gas pedal is like you’re doing leg presses. all joking aside it’s actually too heavy to enjoyably drive

the truck is right outside so I can go outside and look and tell you anything to set the record straight.

I also don’t think it’s overheated. my dad is always watching gauges in the vehicles and the few times I have driven it I always watched them. I had an old nissan pickup that would overheat so I have become overly vigilant since then to pay attention to gauges

 

[kenh]

Pull the dipstick on the trans. If the fluid is "brown" instead of red and smells "burnt", then the trans is probably toast. You could try a fluid change and see what happens. When you pull the pan and it has lots of sludge in it then again it is probably toast. If you see a lot of sludge, metal, brass and shinny steel then it needs a rebuild.

When you start the engine does it drops a cylinder (misses), then after a short time it picks that cylinder up and runs ok? That is a classic example of a blown head gasket or cracked head leaking coolant into a cylinder. Drop the oil and let the first oil dribble out. If you see and coolant then again it can be a head gasket or worse a cracked block.

Ken

 

[marshallsmith27]

is the head gasket miss because of vacuum? and I will check the transmissions in the morning.

It hasn’t been started in a while but I will try and start it tomorrow if I can I hope the gas hasn’t congealed or the spirit evaporated

 

[Schurkey]

First off, DON'T PANIC. Don't be buying engines or transmissions until you've done some investigating.

Pull the spark plugs, perform a cranking compression test. Inspect the plugs for deposits and wear.

Is the engine losing coolant? Is the oil level low? Oil level high?

How old is the gasoline?

"I" would drop the transmission pan, and look for debris. Last time I did that, I found big pieces of the 1--4 band laying in the bottom.

 

[marshallsmith27]

I just asked my dad did he ever check the transmission fluid and now he wants to tell me how much he knows is wrong with the truck. He said the rear main seal in the transmission needs to be replaced but he also said the whole transmission needs to be replaced. Then he started listing off things inside the engine that need to be replaced. I have asked him a number of times what is wrong with it and all he has said is he doesn't know.

My dads friend is the head mechanic for the oil refinery where they both work and he apparently has a transmission for the truck. he is the one that has told him whats all wrong with the truck. I didnt realize this because I have asked my dad so many times what is wrong and he would never say.... the oil refinery has only ever had GMC trucks for as long as I can remember going down there as a kid so I would think he probably knows the truck pretty well. I'm kind of stuck though because if I rely on my dad and his friend nothing will ever happen to the truck. my dad has been going to fix it for 3 years and that probably wont happen.

I guess my grandfather must have drove it too long with low fluid and destroyed the transmission. so with that out of the window if I can find a transmission for cheap. I'm not sure how much a used transmission for the v6 costs I can source that myself...

now that leaves the engine. He said something about valves but I couldn't really hear what he was saying. he said about four or 5 different things it needed. it didnt sound like a complete rebuild to me

I'm no auto mechanic but I do my own work on my motorcycles and have taken camshafts out of those and other things so I might be able to do this truck. I will ask him again and get him to tell me what the engine needs or call my dads friend, that is if he even remembers what it needs

 

[marshallsmith27]

if I did hit up a junkyard that has a transmission with a "known history" how much do they run?

 

[kenh]

is the head gasket miss because of vacuum? and I will check the transmissions in the morning.

No. When the engine stops running the pressure in the cooling system forces coolant into the cylinder through the crack. Another test is to measure the cooling system for exhaust gasses. There are test kits for that I think even available on amazon.

Ken