Vortec 454/4L80e HD swapped 1999 Tahoe OBS

[bigfootchiro]

Why so much?

Because they say it’s too old, so they have to pull it from the archives. You know, someone has to walk to the back of the library where all the dusty files all, look through each VIN in alphabetical/numerical order, and then blow the dust off. Then they have to walk back to the computer, scan the dinosaur files in through the old Kodak, and email through AOL dial up...

Or click “Archived Files” on their computer and search... that sounds better.

 

[swathdiver]

Ok, my searching says the L21 was used in the P12 and the L29 was used in the P30/P32 and was VIN J for 1998. So you're right. Now to find a "book" about that motor!

 

[bigfootchiro]

Ok, my searching says the L21 was used in the P12 and the L29 was used in the P30/P32 and was VIN J for 1998. So you're right. Now to find a "book" about that motor!

Going to need a book, because I’ve been searching for hours trying to find that damn vacuum line!

 

[swathdiver]

Because they say it’s too old, so they have to pull it from the archives. You know, someone has to walk to the back of the library where all the dusty files all, look through each VIN in alphabetical/numerical order, and then blow the dust off. Then they have to walk back to the computer, scan the dinosaur files in through the old Kodak, and email through AOL dial up...

Or click “Archived Files” on their computer and search... that sounds better.

Hey Nate, the motor comes up on the ACDelco website as does the P30 chassis. I started to look around but my eyes are shot from looking at these screens all week. Gotta take a break now from the computer.

 

[bigfootchiro]

Hey Nate, the motor comes up on the ACDelco website as does the P30 chassis. I started to look around but my eyes are shot from looking at these screens all week. Gotta take a break now from the computer.

Hey I appreciate it! No diagram around shows what that part is. Matt ended up calling the dealership for me and they found the part. Why it doesn’t show up anywhere else, I have no idea.

 

[Tonyrodz]

Hey I appreciate it! No diagram around shows what that part is. Matt ended up calling the dealership for me and they found the part. Why it doesn’t show up anywhere else, I have no idea.

View attachment 225279

So now what?

 

[bigfootchiro]

So now what?

Well, I tried to redneck something together, but they didn’t have all of the right parts to do it. So I needed up twisting the hose around til it got a good seat in the valve cover, then used a gear clamp on the intake side. Seems to run ok right now, and it definitely affected the fuel trims. Now it’s time to drive it more and see if they level out

 

[bigfootchiro]

So the engine seems to run ok right now. Better than it has in a while, but I know there’s still some more fine tuning to do; however... TRANSMISSION!!!

4L80E!!!!!

We got it to act up with the scanner hooked up. You’ll be driving along in 4th, the TC won’t lockup, but the scanner will say it wants to lockup. Then all of a sudden, it will kick down out of 4th, into 3rd, and once that happens, it will start hard shifting. It will ONLY hard shift after it does this, never at any other time. If I leave it in 3rd, it’s fine. It will usually lockup in 3rd too (if I have the shift lever in 3rd), but hasn’t been doing that either. Transmission temperatures will start to climb once this happens, but won’t go above 210. All other times it runs around 170-190. Also get a “dragging” feeling after, as well.

Side note: the transmission was overfilled by about a quart. Don’t know how, but it was. We drained that out, and still no change.

Fluid looks and smells fine.

Is there any way to check the TC specifically without pulling the transmission? Maybe something in the wiring? Idk how to Ohm test those wires or anything. Electrical is not my forte, nor are transmissions lol.

 

[kbuskill]

So the engine seems to run ok right now. Better than it has in a while, but I know there’s still some more fine tuning to do; however... TRANSMISSION!!!

4L80E!!!!!

We got it to act up with the scanner hooked up. You’ll be driving along in 4th, the TC won’t lockup, but the scanner will say it wants to lockup. Then all of a sudden, it will kick down out of 4th, into 3rd, and once that happens, it will start hard shifting. It will ONLY hard shift after it does this, never at any other time. If I leave it in 3rd, it’s fine. It will usually lockup in 3rd too (if I have the shift lever in 3rd), but hasn’t been doing that either. Transmission temperatures will start to climb once this happens, but won’t go above 210. All other times it runs around 170-190. Also get a “dragging” feeling after, as well.

Side note: the transmission was overfilled by about a quart. Don’t know how, but it was. We drained that out, and still no change.

Fluid looks and smells fine.

Is there any way to check the TC specifically without pulling the transmission? Maybe something in the wiring? Idk how to Ohm test those wires or anything. Electrical is not my forte, nor are transmissions lol.

Not saying this is your issue... BUT

I have ran across overfilled transmissions that were inexplicable only to find that the filter had come loose and dropped into the pan which displaces the fluid and makes them appear over filled.

This usually is only able to happen when someone installs the shallow filter into a deep pan.

 

[bigfootchiro]

Not saying this is your issue... BUT

I have ran across overfilled transmissions that were inexplicable only to find that the filter had come loose and dropped into the pan which displaces the fluid and makes them appear over filled.

This usually is only able to happen when someone installs the shallow filter into a deep pan.

It’s worth a shot to see! Probably getting to the point of dropping the pan anyway. What else can be checked while it’s dropped? OD clutches? How can you test the TCC solenoid?