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Discussion Starter #1
First off, I am looking to have the Chevy NV4500 with the 6.34 1st gear gearing.

Bought and parted out a 94 Chevy 2500 with a NV4500. Bell-housing bolt pattern matches up to that of the 92-94 GM cases, as well as the ~2.5 inch protrusion on the driver side of the case to be able to hold the taller gearing inside versus the later GM and all dodge years that had only ~1 to 1.5 inches of a protrusion. Unfortunately at that time I was un-sure exactly the full plan of the build but the truck was to hard to pass up on cause of the price. So the bell-housing was sold with that engine :mad::cry:

Fast-forward to know, found another GM NV4500 with the same 92-94 case and bell-housing and protrusions that had the bell-housing, so i snagged the whole thing. It has an ID tag stamped for a 93 year, who knows if that's accurate, but the bell-housing bolt pattern as well as the length of the protrusion those two are dead give away's of it being the correct year case as well.

Know trying to figure out which is the 6.34 1st gearing or the 5.61 1st gearing.......I say this because once I pooped off the top and counted gear teeth this is what I came up with.

For the 94 GM from the front of the case going towards the rear on the main shaft it has 22, 29, 37, 39, 39 tooth counts

For the 93 GM again from the front of the case going towards the rear on the main shaft it has 20, 28, 37, 39, 39 tooth counts.

I've attempted the old fashion route of simply turning and counting the input shaft revolutions to see how many revolutions until the output shaft completes its rotation, but one is ~390 degrees of rotation while the other is only ~330 degrees of rotation. SO WHICH IS THE 6.34 and WHICH IS THE 5.61?

To my thinking the ~330 rotation one is the 6.34 RIGHTTTTT??? o_O馃憖馃憖

I've called around to a couple different shops and they all seem to get lost or have no clue about the exact specifics of the NV4500.
 

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Discussion Starter #3
Turn input 1 revolution. Count tailshaft revolutions.
I've attempted the old fashion route of simply turning and counting the input shaft revolutions to see how many revolutions until the output shaft completes its rotation, but one is ~390 degrees of rotation while the other is only ~330 degrees of rotation. SO WHICH IS THE 6.34 and WHICH IS THE 5.61?

To my thinking the ~330 rotation one is the 6.34 RIGHTTTTT??? o_O馃憖馃憖
 

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Put transmission in first. Turn input six full rotations.
If output turns more than a full rotation then it's 5.xx.
If output turns less than a full rotation then you have the 6.xx

The other option would be to open it up and count teeth.

Sent from my SM-N950U using Tapatalk
 

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Discussion Starter #11
Put transmission in first. Turn input six full rotations.
If output turns more than a full rotation then it's 5.xx.
If output turns less than a full rotation then you have the 6.xx

The other option would be to open it up and count teeth.

Sent from my SM-N950U using Tapatalk
Thats what I thought about spinning and counting revolutions. But turns out that with counting the revolutions and some googling found out that 3rd gear tooth count for botg gear ratios as well as the input shaft tooth counts for both as well and turned out that the one I most recently picked up is infact the 6.34 gearing....Phewwww got lucky on that one. Atleast that tells me the ID tag on it is probably originally as well as the entire tranny. Its 2X4 configured but whatever, was gonna upgrade the main shaft any how.



Sooooo anyone wanna buy a 92-94 GM NV4500 thats 4X4 with the 5.61 gearing......HAHAHA
 

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The 5.61 nv4500's are more desirable for highway driving in 3/4-ton trucks. The gearing matches up better.

I assume you have a 95 transmission, that someone swapped into a 92-94 at some point in the past. The 95 used the later ratios, and earlier external slave bell.

I'd suggest marketing it as a manual swap for 88-98 trucks, or a 5-speed swap for 73-87 2wd trucks. The external slave won't fit well in a 73-87 4wd with a passenger side driveshaft.
 
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