94 Chev. K1500 350


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Old 05-13-06, 06:01 PM
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94 Chev. K1500 350

I have a 94 Chevy pickup K1500 with the 350 in it and four wheel drive. I have two problems.

Problem number one is oil pressure. I get a hard knock at start up and idle. When going down the road I get a reading just under 40 on the oil gage. I had suggestions of a plugged oil pickup screen or a bad pump. Today I spend about 6 hours dropping the pan and putting in a new oil pump. Screen wasn't plugged by the way. Now, I had oil pressure at first for about 15 minutes of run time...higher than I had before and well above the 40 on the gage going down the highway. However, after that initial period the knock has returned and my pressure gage goes into the red at idle again. Any thoughts what might be causing this???

Second problem is on the same truck with the four wheel drive. It will not shift into four wheel drive. I took the actuator out of the front axle and it will go in and out with someone operating the shifter in the truck and the key on. The switch that is screwed into the axle works when I have it out of the axle and manually push it in and out. However when the truck is running and I shift it to four wheel drive I get nothing...the lights on the indicator stay out and it does not engage. Any thoughts on this one?

I know, probably two major problems...but I'm sort of at a dead end so any advice is appreciated!

Thank you!

Brad
 
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Old 05-13-06, 09:19 PM
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Originally Posted by werneb01
I have a 94 Chevy pickup K1500 with the 350 in it and four wheel drive. I have two problems.

Problem number one is oil pressure. I get a hard knock at start up and idle. When going down the road I get a reading just under 40 on the oil gage. I had suggestions of a plugged oil pickup screen or a bad pump. Today I spend about 6 hours dropping the pan and putting in a new oil pump. Screen wasn't plugged by the way. Now, I had oil pressure at first for about 15 minutes of run time...higher than I had before and well above the 40 on the gage going down the highway. However, after that initial period the knock has returned and my pressure gage goes into the red at idle again. Any thoughts what might be causing this???

Second problem is on the same truck with the four wheel drive. It will not shift into four wheel drive. I took the actuator out of the front axle and it will go in and out with someone operating the shifter in the truck and the key on. The switch that is screwed into the axle works when I have it out of the axle and manually push it in and out. However when the truck is running and I shift it to four wheel drive I get nothing...the lights on the indicator stay out and it does not engage. Any thoughts on this one?

I know, probably two major problems...but I'm sort of at a dead end so any advice is appreciated!

Thank you!

Brad
These are fines trucks worth fixing, I just sold my K1500 1992 Suburban, got a K2500 2000 Suburban for my wife, anyways, 4x4 you should take it to the pro's to get it fixed it does sound like some major problem ...
On the knocking, since you replaced oil pump try switching to a higher quality engine oil like mobil 1 or castrol fully synthetic, it does make a difference I witnessed on my old suburban with the 350 on it, better performance and better protection for engine.
 
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Old 05-14-06, 03:58 PM
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You could place your fingers on your oil pan or make a stethoscope and put it against the oil pan and hear if a rod bearing is letting loose. Maybe too much oil is leaking out of the crankshaft at that point causing the pressure drop.

Have you ever run your engine real low on oil or not changed it regularly?(especially if you never had to hardly add any)...or bought the vehicle from some party where you don't have a clue how they took care of it?

MY 350 got about 240,000 miles on it, including not changing the oil for 80,000 miles (seriously), because I decided to not fix the oil leak so the oil always stayed honey colored from me having to add it. It ran like a top up until the rear end's 90 weight ran out on me, and the rear end yoke started to pull out of the pumpkin. But the engine still runs like a top.

By the way; I tryed to fix the rear bearing by squeezing in the "crush bearing", and it worked..for 2 1/2 minutes...and failed. I had a smile on my face as I was backing it out of the garage, and then it failed right back to square one. And I crawled back under the truck only to find the rear yoke the pinion is connected to, pulling right back out of the pumpkin again. (And when that happens, the pinion gear begins pulling away from the ring gear...and then you are caput). Bummer. And to crush a "crush bearing" is not easy, especially laying under the truck. Even with a 4 foot (or was it 6 foot?) cheater pipe on the end of a ratchet.
 
 

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