Where should I begin?????

[corndoggydogg]

Hello all. I am brand new to this message board. On Monday, I acquired a 1970 GMC C1500 long bed w/ a 350 V8, Edelbrock carb, headers and dual exhaust. Engine and transmission have some leaks, but I do not know the extent yet. Not sure if the engine is original (looks pretty old). Due to the lack of oxidation, the transmission appears to be newer. Body and interior are in pretty good overall shape. Heavy rust in bed, some under the carpet and in the rocker panels. Lots of gunk and grease underneath the vehicle. Brakes squeek a little bit and the steering is not very responsive (feels "soft" if that means anything to you). I have a feeling this truck was once a hot rod, but has been neglected for a number of years. I've already degreased under the hood. My first thought is to change all of the fluids ASAP. I want to get this is good working order before I tackle any cosmetic issues. This is my first project vehicle, and I'm not a mechanic, so I am looking for some tried and true advice on what my game plan should be. Budget is NOT unlimited, and I plan to take my time restoring it. Hoping I don't have to drop a new engine or transmission in...we'll see. Thanks in advance for any insight you can provide.

[Big John Sny]

The rear seal on the transmission is pretty easy to replace and probably not bad insurance to make sure you don't run it low, once you identify the transmission. Determine where the engine oil is coming from at the base of the intake manifold.

[Saclandman]

Nice truck. Looks cleaner than a lot of the projects I've seen on here including my own. I think your first priority, after replacing all the fluids, would be to get the tranny seal replaced. Brakes should be gone through as well. All go and no stop would be a bad thing. Good luck.

[midniteblues]

good looking project you got there.
that rust in the bed isnt bad at all
three things i allways check and get right
before moving forward on a driver.
1. brakes
2.steering
3.tires
so you're on the right track.

it looks too me like your drive shaft is way too long
there is no "slip" in your yoke. that'll break alot of something's very quickly
I would suggest that that gets fixed before you drive it even a good bump can and will ruin your trans or driveshaft or alot of other things.

my kid just went through this half his drive shaft dissapeared doing 65mph

[hugger6933]

That is a turbo 350 trans by the way in case you were wondering. Now get the truck stopping and steering. Once the truck is safe for you your family and whoever you meet on the road, not only will the cosmetic be less important [as much as it pains me to say being the owner of a body shop] it will be much more fun to drive and more enjoyable in general to have a project. The more things you can do while keeping it were you can still drive or having it close to driving in just a matter of moments the better off your gonna be. A lot of projects get stalled out when somebody dives into a project and the tear down is fun and then the next you know you have a big room full of parts you took apart and not real sure where they go. If you were to have the truck all scattered out and then get to a point of being unable to put it back together and then get overwhelmed or discouraged then give up nobody but the flipper that comes by picks up the pieces and put it back together and then sells it wins. So don't let that happen to you if at all possible. Now I'm not a good one to follow my own advise as I have one that started with a spark plug change that is torn down to the frame and now is gonna be a rotissere redo. but that is not a big concern for me as I do these or ones like them all the time. Newer or older they are all just parts and I can get them back together. Jim

[sstaten69]

Nice looking start you got there nothing looks to be to bad. Try taking the intake bolts out one at a time and clean them up and put a little permatex non hardening on the treads and tighten it back up should stop oil from seeping past the threads. That's what we had to do on my sons truck. Have fun.

[70LonghornCST]

Welcome to the site! Great looking project. Can't wait to see you get it to where you want it.

[mechanicalman]

Rule #1 when fixing oil leaks: Start at the top and work your way down.

When you replace the rear trans seal, take into consideration the bushing in the tail housing (if it needs replaced or not), and the driveshaft yoke may be worn/grooved as well. The tail housing comes off easy if you have to replace the bushing, it has a square o-ring seal.

midniteblues has a point, the driveshaft yoke appears to be very close to the trans tail housing. Some models had a "slip joint" built into the first driveshaft coming out of the trans IF you have a 2-piece driveshaft, and the yoke might actually bolt into the trans output shaft. A lot of T400's had that set-up, yours looks like a T-350.

I assume being a GMC you have leaf springs, not sure if that means 1 piece driveshaft. I don't think a 1 piece driveshaft would have a slip-joint but I could be wrong.

If no slip-joint, it's pretty close to the trans. If you have leaf springs, when you accelerate, the pinion on the rear end pushes upward pulling the yoke away from the trans, and when you put on the brakes it pushes downward again pulling the yoke away from the trans. So, IF it's leaf springs, it probably only moves away from the trans on accel/decel and will never hit the housing as long as the spring bushings stay good and nothing breaks. Hey, it's made it this far without hitting?

[Tango59]

My 69 had front, rear and speedo connector leaks (TH350)... Took it to an AAMCO shop and all were replaced including the pan which was beat up for less than $300. O-ring at the shifter is leaking now tho. I'll take it back when I get the springs and shocks on it.

[SuperC10Tex]

Welcome from Texas!! Nice looking 4-eyed

[corndoggydogg]

Thank you all so much. I really appreciate the thoughtful responses to my post. I really appreciate it.

Checked and replaced all fluids this weekend. PS fluid was bone dry.

Also changed the plugs, thoroughly sprayed the carb with cleaner, and replaced PCV valve. Degreased the entire undercarriage and under the hood.

In hindsight, I probably should have done these 1 at a time, because now, the vehicle sputters out once I put it in gear. It ran well my first few trips around the block. But after about 5 mniutes of driving, the problem started. Hoping the carb just needs adjustment? The old plugs I pulled out looked pretty rough, so I can't imagine the new platinum plugs are the problem. But maybe that plays into the problem somehow (too much spark)? Anyone have any similar issues like this in the past?