Suggestions for diagnostic elimination of possible causes?


Asked by Aug 14, 2014 at 07:08 PM about the Chevrolet Silverado 1500

Question type: Maintenance & Repair

I purchased used vehicle specifically to do some hauling, expected load approx. 3500 lbs. When vehicle was delivered, it lost oil pressure enroute home, down to 0, so it was left at my mechanic's shop. Sending unit(?) changed, he said it seemed fine.

Automatic transmission shift lever seemed sloppy (and could be "flopped around" by hand) and hard to move to me, and ignition switch sometimes "finicky."

Took off with trailer, within 4 miles, lost oil pressure again--gauge down to 0. No change in engine temperature, no noticeable engine noises like ticking or tapping or worse.

Ran several miles, stopped for two traffic signals. My sister heard high rpm from motor before transmission shifted at first stop. At second stop, I noticed the high rpms as I pulled out, and took my foot of the gas to encourage transmission to shift. Engine stalled, would not start up. My cousin noticed that when I tried to start, the hot battery cable (that runs to starter?) "jumped."

Truck taken back to shop on flatbed. Mechanic says he can't move drive shaft (?) and engine is seized. He says without dropping transmission (about 6 hours), he can't easily determine if problem is in engine or transmission.

Any suggestions? I took out a loan for this vehicle.

7 Answers

First of all it does NOT take 6 hours to drop a transmission. Any shade-tree amateur mechanic can do it in a couple-three hours. At a shop with a lift, and experienced mechanic an hour or so . From there your question gets more difficult, loss of oil pressure could be a failed oil pump, and how your loss of oil pressure and transmission shifting problems are related....?

3 of 3 people found this helpful.

I'm thinking you have an electrical problem of some kind. First thing I'd do is remove all the spark plugs and try to turn the engine by hand. If you can turn the engine by hand it's not seized. What year is your Silverado? Is it a stick or automatic? How many miles are on it? Check for blown fuses and, since you just bought it, check for damaged wiring harnesses. Someone may have rigged it up some how. HTH. -Jim

1 of 1 people found this helpful.

Many years ago I knew a lady that had the transmission STOLEN right out of her Ford Fairlane ...get this...while she was in the grocery store, less than 30 minutes. Hard to believe I know but I came to get her, a neighbor, it was just flat gone..unhooked shift linkage, four nuts on U-Joint, slip out spline, and five bolts on bell-housing. before the days of cameras everywhere

3 of 3 people found this helpful.

Bought from a friend that has a small engine shop and has done all my lawn mower work for 10 yrs +. He towed with it a lot. Has 250,000. 2002 4x4, Automatic. Mechanic says he can't get to one of the bolts because (something about) of the position of the engine? He has done my work for about 20 yrs., small shop, he and one employee.

2 of 2 people found this helpful.

I'm still leaning toward an electrical problem. I believe the drop in oil pressure was a false reading. As I suggested earlier try spinning the engine by hand. Another thing, switch on the headlights and try to crank it. Do the lights stay nice and bright or do they get very dim or go out. If the torque converter clutch (TCC) in the transmission is stuck on (locked) it will prevent the engine from turning as well. What exactly do you mean by the battery cable "jumped"? Did it spark, move, what exactly happened? HTH. -Jim

1 of 1 people found this helpful.

Jim, thanks for your thoughts on this. By "jumped" I mean moved. I didn't see it as I was in the truck, trying to start it.

1 of 1 people found this helpful.

You're welcome. Glad to help. Check the bolts that hold the starter to the engine. Be sure they're tight. For the battery cable to move like that it sounds like the starter is "flopping around". This is not good. The starter is actually grounded by the engine block. So if it's not mounted securely it won't be properly grounded and may not crank. HTH. -Jim

1 of 1 people found this helpful.

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