NV4500/NP205 Rebuild First Impression

[SquareRoot]

Well, I have been driving the beast to work for a few days since the overhaul. First impressions:

1. The 5.61 version is so much more street friendly than the 6.34 it replaced!
2. It shifts unbelievably smooth. Like butter smooth. Kudos to the carbon syncros.
3. The 205 t-case and Twin Sticks are just awesome! Having front wheel drive only in hi or low is interesting.

4. The transmission is NOISEY! Yup, I was disappointed when I fired it up, put the T-case in neutral and the trans in gear and heard that noise! After months of meticulously tearing this trans down and replacing every bearing, race, thrust washer, shift forks, reverse clutch, input shaft springs, syncro's etc., with premium parts, it sounded not much different than the one I took out. WTF? I inspected every parts dimensions and assembled it exactly to spec including torque values and the tight side of clearances. Yet, noise. Like gears banging around.

So, I started digging around on the internet. Little did I know beforehand, it is the nature, even reputation of the 4500 to be noisy beasts. I figured the one I had in previously, a craigslist find with unknown miles was just worn out, thus the noise. To my surprise I found literally hundreds of posts on the subject and many guys having the exact same experience. Even dealers back in the day, would tell returning buyers, it's normal, noting we can do about it. Even guys who bought new transmission say they are noisy. The consensus is the noise does not affect the trans, people run them for decades, pull them apart and they look brand new inside. The theory is its gear backlash and the gears in this trans are huge. In certain gears the massive countershaft isn't under load and engine harmonics cause the gears to rattle around. At any rate, I know the trans is put together right with good parts so I'll just run it like everybody else.

With all the interest on this trans, has anybody else had noise experience with it in any of their trucks (Squarebody or otherwise)? @Frankenchevy

 

[BearKing]

What year truck is this in and do you have details like did you need to buy an Advanced Adapter to mate them together? Maybe a few pictures? This is relevant to my interests. Thinking about going this route. Any help would be greatly appreciated. Thank you, sir, in advance.

 

[SquareRoot]

What year truck is this in and do you have details like did you need to buy an Advanced Adapter to mate them together? Maybe a few pictures? This is relevant to my interests. Thinking about going this route. Any help would be greatly appreciated. Thank you, sir, in advance.

85. Yes, I used the AA bellhousing. There are many threads on hear with pics. Do a search for NV4500, Myself and @Frankenchevy both went thru it although he retained the NP208 t-case.

 

[Frankenchevy]

Well, I have been driving the beast to work for a few days since the overhaul. First impressions:

1. The 5.61 version is so much more street friendly than the 6.34 it replaced!
2. It shifts unbelievably smooth. Like butter smooth. Kudos to the carbon syncros.
3. The 205 t-case and Twin Sticks are just awesome! Having front wheel drive only in hi or low is interesting.

4. The transmission is NOISEY! Yup, I was disappointed when I fired it up, put the T-case in neutral and the trans in gear and heard that noise! After months of meticulously tearing this trans down and replacing every bearing, race, thrust washer, shift forks, reverse clutch, input shaft springs, syncro's etc., with premium parts, it sounded not much different than the one I took out. WTF? I inspected every parts dimensions and assembled it exactly to spec including torque values and the tight side of clearances. Yet, noise. Like gears banging around.

So, I started digging around on the internet. Little did I know beforehand, it is the nature, even reputation of the 4500 to be noisy beasts. I figured the one I had in previously, a craigslist find with unknown miles was just worn out, thus the noise. To my surprise I found literally hundreds of posts on the subject and many guys having the exact same experience. Even dealers back in the day, would tell returning buyers, it's normal, noting we can do about it. Even guys who bought new transmission say they are noisy. The consensus is the noise does not affect the trans, people run them for decades, pull them apart and they look brand new inside. The theory is its gear backlash and the gears in this trans are huge. In certain gears the massive countershaft isn't under load and engine harmonics cause the gears to rattle around. At any rate, I know the trans is put together right with good parts so I'll just run it like everybody else.

With all the interest on this trans, has anybody else had noise experience with it in any of their trucks (Squarebody or otherwise)? @Frankenchevy

Definitely a truck transmission. I have both nv4500 and nv5600 equipped trucks. They definitely have some character. Not made for rowing through the gears at speed, though it can be done.

I’m still on the fence about staying with the nv4500 or going 4L80 in my square.

 

[Rustisbest]

Are you using a stock rubber isolated shifter handle?
I swapped one in my Tahoe with a 241 t case and it's only noisy in 5th gear. The aftermarket Core shifter i bought amplifies everything because I can grab the handle and it shuts up.
I'm guessing the gear driven 205 probably makes yours worse also.

 

[Frankenchevy]

For the record, mine only produces noise in neutral. No noise in gear…

 

[BKING33]

Mine is same way. Very noisy just in neutral. I have driven it about 30,000 miles. Unknown condition and mileage on transmission
before I bought it.