88GMCtruck's 98 Silverado Towpig Build: "Black Fox"

[BowtieBrody]

..Miller welder. I was being a smart ass.

And you're right sir, that belongs in a GM brochure for sure. Lookin good

I was gonna say ticky-tack that retainer on there but I didn't wanna look like a fool

 

[Biggershaft96]

Nut has two set screws with brass pads under them...

damn. i cant belive it still backs off. ive made ALOT of set screw nuts and never seen one back off. does it mess up the threads of the main shaft when those come off?

 

[RDF1]

Is the shaft hardened? I'd figure drilling shallow blind holes and tighten the set screws in them and it should be solid.
We do that on some of the parts we manufacture and never had a issue. But no vibrations like what a transmission would see.
That's crazy.

Sent from my SAMSUNG-SM-G870A using Tapatalk

 

[leakers]

Loctite 620 ? I know it is not really the correct application, Loctite would recommend 272 or possibly 2760. However I have used 620 on a gearbox shaft nut on my Vincent V twin , it has been the ONLY cure that worked , and has thus far lasted nearly 40 years , after previously coming apart about every two years. I have since used 620 and even 680 as a threadlocker many times , You will need heat and a heavy duty impact driver to break it loose.

 

[88GMCtruck]

..Miller welder. I was being a smart ass.

And you're right sir, that belongs in a GM brochure for sure. Lookin good

I was gonna say ticky-tack that retainer on there but I didn't wanna look like a fool

Most of the time (at least with dodges) when they get welded on it ends up breaking the shaft... dunno if that would be the case for me or not.

damn. i cant belive it still backs off. ive made ALOT of set screw nuts and never seen one back off. does it mess up the threads of the main shaft when those come off?

Since they use brass pads it does not significantly, but once the nut backs off the press fit of the shaft is kinda trashed.

Is the shaft hardened? I'd figure drilling shallow blind holes and tighten the set screws in them and it should be solid.
We do that on some of the parts we manufacture and never had a issue. But no vibrations like what a transmission would see.
That's crazy.

I'm sure it is.

Loctite 620 ? I know it is not really the correct application, Loctite would recommend 272 or possibly 2760. However I have used 620 on a gearbox shaft nut on my Vincent V twin , it has been the ONLY cure that worked , and has thus far lasted nearly 40 years , after previously coming apart about every two years. I have since used 620 and even 680 as a threadlocker many times , You will need heat and a heavy duty impact driver to break it loose.

Well the trans shop is doing the work so it's on them IMO... and they know these transmissions.

 

[98chevy2500SS]

@88GMCtruck, for your parking lights on your dually, did you use LEDs instead of the incandescents? Not sure if I am liking my LED parking lights that look like this: https://www.amazon.com/VIPMotoZ-199...21&ymm=1998:chevrolet:k2500&keywords=vipmotoz

 

[88GMCtruck]

@88GMCtruck, for your parking lights on your dually, did you use LEDs instead of the incandescents? Not sure if I am liking my LED parking lights that look like this: https://www.amazon.com/VIPMotoZ-1998-1998-Chevrolet-Blazer-Bumper/dp/B07481ZDDV/ref=sr_1_21?s=automotive&ie=UTF8&qid=1528658628&vehicle=1998-47-458-440-29--9-8---9-2---1-0&sr=1-21&ymm=1998:chevrolet:k2500&keywords=vipmotoz

Yup, they are just LED drop in bulbs in my TYC housings.

 

[Blackwater]

https://www.midwesttrans.com/NV4500/nv4500.html

This site has all your NV4500 needs and questions including the 5th backoff and has cryogenic shafts and parts.
Yours must be the MT8 if it doesn't have a nut on the 5th. when I upgraded my NV3500 MG5 to the NV4500 MW3 in my GMC 93 C1500, I learned that it had a locking bolt on it and if it does come off or I break something when I drop my stroked vortec max engine in that he has parts that are used in sled pulling that wont break in my application. Hope this was useful.

 

[98chevy2500SS]

Yup, they are just LED drop in bulbs in my TYC housings.

Cool, thanks man.

 

[88GMCtruck]

https://www.midwesttrans.com/NV4500/nv4500.html

This site has all your NV4500 needs and questions including the 5th backoff and has cryogenic shafts and parts.
Yours must be the MT8 if it doesn't have a nut on the 5th. when I upgraded my NV3500 MG5 to the NV4500 MW3 in my GMC 93 C1500, I learned that it had a locking bolt on it and if it does come off or I break something when I drop my stroked vortec max engine in that he has parts that are used in sled pulling that wont break in my application. Hope this was useful.

So, a few things -

That is where my transmission is from. The 5th gear nut is on ALL NV4500s, 2wd, 4wd, chevy, dodge.... The factory NV4500 nut is just a fine thread nut - no locks. The locking nuts are aftermarket and there are a few varieties out there.

The main difference is the Dodge trucks typically have the problem with 5th gear backing off. GM generally doesn't have that issue, and there were much fewer GM NV4500 trucks. There are many locking methods for the Dodge 5th gear issue that don't exist for the GM versions - including splined nut retainers and various aftermarket locking shafts. GM only has the option to use the locking nut, and there are no aftermarket locking shafts or splined retainers available.

The difference between the MT8 (92-94) and MW3 (95+) GM NV4500 is the external VS internal slave cylinder, bottleneck vs bolt on shifter, and gear ratios. Both have the same locking nut and possible 5th gear problems. Of note, 95 is an oddball year, higher ratio gearing with external slave cylinder and bolt on top cover... 95 is just a weird year overall.

Now, a large difference with GM vs Dodge is the placement of the 5th gear nut. GM uses two sets of press splines on the back, one for the 5th gear and a second one for a harmonic damper, then the nut is installed. The harmonic damper was used early on, mostly in 6.5L applications but it's indicated in the GM EPC that they were also installed on 5.7L and 7.4L trucks. Later on the dampers weren't used and there was a steel sleeve installed between the 5th gear and the nut, over the splines. Dodge did not have a damper or spacer.

In my application, when 5th gear backed off, it was close enough to the transfercase input shaft that it presses into it, and takes out the input of it. On a Dodge, without the spacer or damper, the gear can move back and simply free spin on the shaft, without hurting the transfercase.