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2000 chevy t case, which one?

939 views 8 replies 2 participants last post by  pyrowaves 
#1 ·
Silverado 6 L. with push button 4x4.
Should be a 246 correct?

but isn't there a 27 spline and 32 spline?
How do I tell which one I have without pulling it out and counting?
 
#2 ·
what model truck do you have? standard 2500? should be a NP246. if yours came with a 4l80e then it should be 32 spline input. crawl under get the id tag, and or go in the glove box for the RPO code to make sure you buy the correct t-case if thats what your replacing.
 
#4 ·
this is how the junkyards separate the t-cases for a 2500. i never knew they put a 4l60e in a 2500 until just now. especially behind a 6.0.

dash switch (elec shift), 4L60E
dash switch (elec shift), 4L80E
floor shift, AT, (4L80E)
floor shift, MT, MG5
floor shift, MT, MW3
 
#7 ·
looks like he has an NP1 and I have an NP8

I wonder if they would work. He has the 4 button auto t-case. His is a 2001. I found this on another forum.


In 2000 there was only one choice for a 2500. In 2001-2004, GM offered an "HD" model with a significantly higher GVW and IIRC the engine was either a 7.4 gas or the 6.6 Duramax. Both engines had quite a bit more HP and torque, and the NP8 could not keep up.

So the regular 6.0 2500's got the NP8 autorac and the HD's got the NP1's.
 
#8 ·
if both t-cases are auto-trac t-cases then they should interchange. but if you dont have an auto-trac case you cannot put one in as the wiring is different. i looked up the RPO codes and NP1 is listed as a standard electric shift case where a NP8 is listed as an auto-trac case.
 
#9 ·
ok well I guess he checked again and sent me a picture of his glove box tag and it is an NP8.

He wants 500 for the switches and the t-case. his truck has 160K miles on it but I'm guess with the pump issue on these its had work done to it or been replaced. He is about 20 min from me so i'm going to look at it tomorrow.
 
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