This is from TB56:
My oil pressure gauge pegged to 80psi earlier this week. Called a parts store and got a Borg Warner replacement with lifetime warranty for about $40 dollars. Get yourself a 1-1/16 inch deep socket.
1) The cover needs to come off the top of the motor. One bolt and it was off. 2) location of the oil pressure sending unit is on the rear of the motor, top side slightly to the right of center line of the motor slightly to the drivers side. It is behind the cover you just removed down in the area between the fire wall and the back of the valley in the motor. I had to locate it with an extendable mechanics mirror. Beware, the area you are going to work in is very limited in terms of space. It is a one hand, blind process. That's where the mirror comes in handy. The Sending unit has a plug the connects to electrical system. This connection has a clip mechanism that you need to gently pry off to loosen the clip. Once you get the clip loosened, gently pull up on the connection and it will pop off. Get your 1-1/16 inch socket on the nut. What you are removing is made of very light weight metal. Make sure you get the socket seated well. The 1-1/16 socket I used was 1/2 inch drive. I used a 6 inch extension on the ratchet and with very little force, it loosened. Loosen it until you are able to turn the extension by hand and remove the extension and socket from the area you were in. Carefully reach back in the same area and get the old oil pressure sending unit out. I noticed the factory unit had a yellow grommet in the electrical portion of it. DON'T LOOSE THIS. I looked at the new unit and it did not have that grommet in it. I placed the yellow silicone grommet in the top of the new unit and worked it back into the spot where the nonfunctional unit was removed. Make sure it screws in easily. Get it as tight as you can by hand or with the socket and extension. Attach your ratchet and tighten it down. There is a crush bushing you need to compress for good seating of the unit. Once tight you can attach the connection plug to the sending unit. There is a piece of plastic the is on one side of the new unit, like on the old one that will help you orient the plug connection. The clip will align with the plastic Piece that protrudes from the side of the sending unit. Gently push down and make sure you hear it click. You are almost done, just replace the vortec cover and tighten the bolt down and you are done. It took me about 30 minutes once I found where the sending unit was located. I had an idle pressure of about 40 psi, and as expected, it rose with engine reving. Fixed! A few cuts and scrapes and some contorting over the motor and I was done. There are pictures already on the Tahoe Forum so I opted to try to give as much detail as I could to help you all out. I've got 197,790 miles on this Tahoe and love it. I guess after this many miles, this factory unit finally pooped out. I
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There is also pics provided from mvillani. Both of these are found on the second page of new posts about in the middle of the page related to the same problem. When you open the thread it is all on the second page of that thread.
