Tahoe1986

I've been working on my 2001 Tahoe LT 4x4, transmission went out. The original trans is a 1KCD , I replaced it with a 9LUD from a 99 Suburban 4x4. All the wiring was the same and so was the output shaft. I used the torque converter that came with the 9LUD. Bolt holes didn't line up right to the original flex plate, had to drill a little bit and now it lines up. Bought the spacer/adapter that was needed for the TC - flex plate . Everything is bolted back up, got it started, put it in all gears.... and nothing! Any advice?

LS1Formulation

iTrader: (13)

I'm not familiar with those codes, but I don't think they'll matter with this. The trans is going to be a 4L60-E, period. Aside from the 2500 Suburbans that had a 4L80-E, they all used the same trans. So why did it need an adapter? I'm aware that some '99 model year 4.8s and 6.0s had extended crank flanges, but I haven't been aware of any of those being installed in a Tahoe. Either you just installed a roached transmission, or when you installed the torque converter, you didn't engage the front pump drive lugs. Time to install a pressure gauge on the transmission and see if you're getting line pressure. That would be my first plan of action.

BigBlackCamaro

'99 Suburban's still had the old vortec small blocks.

BigBlackCamaro

If you don't have a pressure gauge I wouldn't run around trying to find one yet.

Do you know if the transmission worked when pulled?
Did you open it up at all before installing it?
What was the torque converter spacing?

In my opinion it's time to take it back out and take it apart.

I bought my first automatic back in 1995 and sure enough it didn't work, so it was my first rebuild. From that point on I bought core transmissions to rebuild so I know they would work. And here it is 2022 and I went and bought a junkyard transmission to just bolt in a car I have just so it'll l move around the yard and maybe go around the block every six months or so. I still opened it up, everything looked ok and it worked. I wouldn't recommend doing that though.

For some reason most of the 4x4 cores I took apart in the past were broken pretty bad.

98CayenneT/A

Did you also swap the bell housing from the '01 Ls over to the '99 vortec 4l60e?

LS1Formulation

iTrader: (13)

Ahh, the '99 model year threw me. I forgot those were still OBS style.

Tahoe1986

Yes I did, took the original bell housing and bolted it right up. Even bought new bolts.

BigBlackCamaro

The bellhousing should have stayed on the new transmission. The LS type bellhousing is deeper and that will pull it too far from the engine. That crank spacer takes up the difference of it being to short so with that bellhousing on it theres even more space. There is probably a pump engagement problem.