NV3500 Help

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Carp0331

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So in doing my build I haven’t really had a chance to drive the truck much since purchase. When I have driven it (cammed 5.7 Vortec and carb) I’ve had grinding issues with downshifting to either 1st or 2nd. Shifting thru the gears is fine and no matter how many times I pump them it will still grind. Just ordered a new master cylinder and slave cylinder set up as I noticed the fluid looked pretty dirty. For those with similar issues any luck this will fix it or am I looking at pulling and replacing the synchros and possibly chewed up gears? Would do a nv4500 swap but it’s even less sportier than a nv3500 shifting wise. Might bite the bullet and do a lt1 t56 swap. Just put 2 qts or royal purple synchro max in.
 

geeeee89

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NV3500s don't belong in a fullsize truck, especially not one with any sort of power upgrades.

Mine starting making this nasty grinding noise in neutral with the clutch out, and any time I downshifted into 2nd coming into a turn or stop it made this really S H I T T Y chirping/squealing noise. It would occasionally go away and then come back.

I went and bought a used NV4500 and swapped it out. Direct bolt-in, no other parts needed. I threw the 3500 in the dumpster. Should've taken it for metal scrap though...

The 4500 is definitely a work truck trans and not sporty by any means. But it is very strong and a direct bolt in.

The 3500 is supposed to take some very specific fluid from GM if I remember correctly. Unless you have that, maybe that could be part of the reason it's grinding
 

Erik the Awful

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NV3500s don't belong in a fullsize truck, especially not one with any sort of power upgrades.
That's a modern expectation projected on a transmission that was more than adequate at the time. "My transmission broke" was not a common complaint when these trucks were still under warranty. At the time, anything more than 300 hp was uncommon on the street, and it you had more power, you knew to train your right foot to keep from breaking parts.

First, use the GM transmission fluid. www.amazon.com/ACDelco-10-4006-Synchromesh-Manual-Transmission/dp/B0026JK8FA/

You don't say your year or model, but I believe all the NV3500s have pre-bled clutch hydraulics available cheap. That's the most likely suspect.
 
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geeeee89

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That's a modern expectation projected on a transmission that was more than adequate at the time. "My transmission broke" was not a common complaint when these trucks were still under warranty. At the time, anything more than 300 hp was uncommon on the street, and it you had more power, you knew to train your right foot to keep from breaking parts.
No it's not. It's a perfectly reasonable expectation and I would've had the same expectation in 97 when the truck was new. It s h i t the bed after 100k miles, I'm not expecting too much to ask for a longer service life than that. The truck had even less power in 2018 when the trans took a s h i t than it did in 97 when it was new...my motor has absolutely nothing done to it. I wasn't saying it was inadequate because it couldn't handle upgraded power. That would be certainly be unrealistic because the trans wasn't made for that.

Per the owner's manual, the bumper-to-bumper warranty in 97 was 36k miles. You're saying that since no one complained of "my trans broke" within 36k miles that it's an adequate transmission? WEAK

It's only an adequate transmission for a 4.3 full size that doesn't get used hard, MAYBE a full size with a 350 that is only used for going to the store, not towing/hauling up to its recommended capacity.
 

geeeee89

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First, use the GM transmission fluid. www.amazon.com/ACDelco-10-4033-Manual-Transmission-Fluid/dp/B007Q108YY

You don't say your year or model, but I believe all the NV3500s have pre-bled clutch hydraulics available cheap. That's the most likely suspect.
I agree with these parts though.

OP, start with draining the fluid out and putting the right quantity of the right fluid in there. If that doesn't help you can try the clutch release bearing, but replacing that sucks because you have to drop the trans. If that doesn't fix it...I'd look into a different trans
 

Erik the Awful

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You're saying that since no one complained of "my trans broke" within 36k miles that it's an adequate transmission? WEAK
I'm saying that's what GM cared about most. If yours broke at 100k, my condolences, but I never heard of manual transmission problems from my friends who drove these trucks back then. I think they were more concerned with the flaky paint.
 

geeeee89

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I'm saying that's what GM cared about most. If yours broke at 100k, my condolences, but I never heard of manual transmission problems from my friends who drove these trucks back then. I think they were more concerned with the flaky paint.

Fair enough. I bought the truck with 100k and the trans died at 115 or so, so who knows what the previous owner did with it. I love my 4500 now so I'm glad it happened. I'm fortunate to not have flaky paint...yet
 

1997

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That's a modern expectation projected on a transmission that was more than adequate at the time. "My transmission broke" was not a common complaint when these trucks were still under warranty. At the time, anything more than 300 hp was uncommon on the street, and it you had more power, you knew to train your right foot to keep from breaking parts.

First, use the GM transmission fluid. www.amazon.com/ACDelco-10-4033-Manual-Transmission-Fluid/dp/B007Q108YY

You don't say your year or model, but I believe all the NV3500s have pre-bled clutch hydraulics available cheap. That's the most likely suspect.

no offense, but that's not the right stuff for the 3500.
this is.
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Griffin Meeks

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I just had a similar issue with it being hard to get into first and second, even at a dead stop. There was also a squeaking sound with the clutch fully engaged. When I pulled the transmission, the pilot bearing had chewed itself to pieces, and the throw out bearing was a little bit rough, so I replaced both and everything has been good since. I know the one/two issue was caused by the pilot bearing. I'm assuming the noise with the clutch engaged was the throw out bearing.

For what it's worth, I also took the trans apart to check things over, but everything looked good so I just put it back together without replacing anything.
 

Erik the Awful

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