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?

 

[kbuskill]

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?

Not sure... but James @swathdiver probably knows.

 

[bigfootchiro]

Not sure... but James @swathdiver probably knows.

Thank you! Any information is appreciated, as always, so thank you for your input

 

[swathdiver]

Not sure... but James @swathdiver probably knows.

Not without a manual, sorry. I would hook it up to a Tech-2 and see what's going on when it acts up, otherwise, I'd have to look at a manual or find an expert. Didn't Randy just get a 4L80?

 

[randeez]

Not moving yet.
You need to get some tuning done. After thinking about it, the trans needs to know tire size and gear ratio for shifting and lock up which I'm sure are wrong if you havent touched rv tune

 

[bigfootchiro]

Not moving yet.
You need to get some tuning done. After thinking about it, the trans needs to know tire size and gear ratio for shifting and lock up which I'm sure are wrong if you havent touched rv tune

Shifting and lockup, before this issue occurred, seemed to be perfectly fine. Shifting is still fine, even if I put it in 4th, but the problem arises when TC doesn’t lockup for a while, then kicks down to 3rd. Adaptive tables were cleared in the transmission, thinking it learned something new, and that did not change anything.

 

[bigfootchiro]

Bad news... the P1870 Transmission Component Slipping code is the TC. Guy at transmission shop (I was referred to them by a patient, and he has built and raced many cars) said he would recommend a rebuild anyway. Quoted me at $1700 out the door.

My question to you guys... if I were to rebuild it myself, what kits do you recommend? Deluxe, Master, etc? Also, I would prefer a slightly higher stall TC if going this direction. Seems like you can have all of the parts for around $400-$600 depending on which direction you go.

 

[Tonyrodz]

Bad news... the P1870 Transmission Component Slipping code is the TC. Guy at transmission shop (I was referred to them by a patient, and he has built and raced many cars) said he would recommend a rebuild anyway. Quoted me at $1700 out the door.

My question to you guys... if I were to rebuild it myself, what kits do you recommend? Deluxe, Master, etc? Also, I would prefer a slightly higher stall TC if going this direction. Seems like you can have all of the parts for around $400-$600 depending on which direction you go.

To me--seems a little high--not crazy high tho. What parts do you get for the $1700?

 

[mikeyss]

I thought the P1870 trouble code was just a 4L60 problem. When I had my 95 Impala SS, it always had this code pop up, and then it'd bang through the gears until I stopped and restarted it. From my understanding the sleeve that the Piston activating the TCC swells or something then the Piston can't operate the TCC and pisses off the computer. I didn't realize the 4L80 also had this issue.

When you get the trans apart, I am curious if you have the straight cut planetary gears.

 

[bigfootchiro]

To me--seems a little high--not crazy high tho. What parts do you get for the $1700?

He didn’t say exactly if it was a master or deluxe rebuild, but did say all new clutches, a couple upgraded parts (since there is a 24K/2 year warranty), TC, not sure if all new electronics, and labor.

I thought the P1870 trouble code was just a 4L60 problem. When I had my 95 Impala SS, it always had this code pop up, and then it'd bang through the gears until I stopped and restarted it. From my understanding the sleeve that the Piston activating the TCC swells or something then the Piston can't operate the TCC and pisses off the computer. I didn't realize the 4L80 also had this issue.

When you get the trans apart, I am curious if you have the straight cut planetary gears.

I guess the 4L80 was known for having TC issues. From what you just said, my transmission does the same. When the PCM senses this fault, it goes into a fail-safe mode (not limp) where it increases line pressure to maximum, making sure everything is lubricated so it doesn’t break. If you shut it down, let it rest a few minutes, and start it up, it goes back to normal.

 

[bigfootchiro]

Got some LS injectors on eBay. They aren’t Delphi or Bosch, but they were the only ones that had a consistent amount of good reviews. They are a “Stage 1” upgrade, and are essentially 32lb injectors. I know it will be too much fuel without tuning, but that’s what the 0411PCM swap is for