Pilot Bearing Question

[cebra]

I am having a painfully difficult time trying to figure out what works and what doesn't work to mount a 2000 model NV3500 to a 2000 model 4.8L AT engine. I know the cranks, flywheels, etc. are all different between a 2000 MT engine and a 2000 AT engine and 2001+ MT engine.

Anyways, I have a pilot bearing/flywheel for a 2002 Silverado...does anyone know if this will fit a 2000 AT engine (out of a Tahoe) or in 99-00 AT engine was it still the 1.7" and then changed to 1" in 2001? I would just test it but I don't have the motor and don't want to hold up my swap over having to order a custom pilot bearing.

[kipps]

I'd question your source that says they downsized from a 1.7" to a 1" pilot in 2001.
I put a 1.7" pilot bearing (part #12557583) in a 2010 5.3 gen iv. It fit fine.

[cebra]

Originally Posted by kipps

I'd question your source that says they downsized from a 1.7" to a 1" pilot in 2001.
I put a 1.7" pilot bearing (part #12557583) in a 2010 5.3 gen iv. It fit fine.

I typed that backwards, per below I read on Novak they went from a 1" in 99-00 engines to a 1.7" in both MT/AT engines in 01. However, what I don't know is if they are only talking about the 1" being for MT engines which were different than AT engines cranks in 99-00.

Pilot Bushings

In 2001, GM updated their crank bore design on the V8 as well as the V6, eliminating the smaller, ~1" diameter pilot bushing bore (featured on Chevy engines since at least the 1940's) by extending forward the depth of the larger, 1.7" automatic torque converter pilot bore. For this reason, we offer pilot bushings for both the earlier and later style designs and installers of 1997-2000 Gen III engines with manual transmissions will usually choose a Gen I style pilot bushing.

[cebra]

To anyone doing a manual LS swap, please go with an 01 and later manual transmission and motor and save this headache. I have well over 100 hours of research and I am pretty sure I have not discovered any definitive answers on what pilot, flywheel, and throwout will work.

[cebra]

I hate to say it, I think Novak is not entirely correct on this one and when I called they had 0 knowledge of the NV3500 and really were not any help on the engine crank changes either. I believe what they should say is the pre-2001 MT engine (very different than the AT engines) need a different size pilot. "In 2001, GM updated their crank bore design on the V8 as well as the V6, eliminating the smaller, ~1" diameter pilot bushing bore (featured on Chevy engines since at least the 1940's) by extending forward the depth of the larger, 1.7" automatic torque converter pilot bore." I went to the shop my engine is at and the 1.7" pilot bearing fits the 99-00 AT engines.