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

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Blackwater

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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.


I completely agree with you except the differences on the MT8 Vs MW3. I went with the MW3 because it was fully syncroed and the gear ratios where not as low in the 1-3 gears. 1st and reverse in the first year of the MT8 was 6.34:1, then changed to 5.61:1 in both. first and reverse was not syncroed till the MW3. In 1997 onward the reverse went to 5.04.
 

88GMCtruck

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I completely agree with you except the differences on the MT8 Vs MW3. I went with the MW3 because it was fully syncroed and the gear ratios where not as low in the 1-3 gears. 1st and reverse in the first year of the MT8 was 6.34:1, then changed to 5.61:1 in both. first and reverse was not syncroed till the MW3. In 1997 onward the reverse went to 5.04.
RPO MT8 was used in 92-94. All the MT8 transmission have the lower gear ratios (6.34:1 first). The gear ratios changed in 95 when they started sharing the case/bellhousing pattern as dodge (5.61:1 first). And yes, in 97 reverse changed to the higher gearing as well.

Forward gears were synchronized in all NV4500 transmissions. Many people think that 1st is not synchronized in the early transmissions (92-94) due to the the lock-out feature. 1-2 has a fly-weighted synchro assembly that prevents downshifting into 1st while moving at just about any speed.

Reverse was not synchronized until 99.

There is a LOT of bad information on these transmission specs and what happened what year, but I can assure you that 1st is synchronized with a weighted lockout on early transmissions, and reverse was not synchronized until 99.
 

83GMCK2500

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RPO MT8 was used in 92-94. All the MT8 transmission have the lower gear ratios (6.34:1 first). The gear ratios changed in 95 when they started sharing the case/bellhousing pattern as dodge (5.61:1 first). And yes, in 97 reverse changed to the higher gearing as well.

Forward gears were synchronized in all NV4500 transmissions. Many people think that 1st is not synchronized in the early transmissions (92-94) due to the the lock-out feature. 1-2 has a fly-weighted synchro assembly that prevents downshifting into 1st while moving at just about any speed.

Reverse was not synchronized until 99.

There is a LOT of bad information on these transmission specs and what happened what year, but I can assure you that 1st is synchronized with a weighted lockout on early transmissions, and reverse was not synchronized until 99.

To say nothing of the 1-yr only oddities surrounding the 1995 MY NV4500s. Thanks GM
 

88GMCtruck

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To say nothing of the 1-yr only oddities surrounding the 1995 MY NV4500s. Thanks GM
Form my earlier posting:
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.
 

Blackwater

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But it fits your truck
The most odd ball out there
Also my favorite extended cab

Sent from my SM-S727VL using Tapatalk

I have a 1993 that has between 1992 to 2007 1/2 to 1 ton parts and aftermarket parts. Cant get any oddball than that.
 

88GMCtruck

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But it fits your truck
The most odd ball out there
Also my favorite extended cab
His is a 96.

I have a 1993 that has between 1992 to 2007 1/2 to 1 ton parts and aftermarket parts. Cant get any oddball than that.
There is a difference between being a factory oddball truck, and making an oddball truck.
 

Blackwater

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His is a 96.


There is a difference between being a factory oddball truck, and making an oddball truck.

True. Im taking the best of all the years and putting them together. I will start a thread on it soon. I have a package coming in today with traction bars and rear sway bars
 

94burbk1500

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I can't wait to see that thread, my GMT dream is to have enough time to build a dream truck from parts next time I visit the USA. I have a friend in Portland and another in Vancouver BC , both have workshops and are GMT400 guys.
GMT 400s are so expensive in New Zealand that every time we repair one here it becomes an oddball. None of us knows enough about the minor differences and idiosyncrasies from model year to year to be definitive. In fact most repairs are done with whatever parts we can find and apply.
I have a bunch of parts trucks and parts, but still come up short and have to airfreight parts to keep trucks on the road.
Check this out for prices.

https://tinyurl.com/y8v8nnca
Those prices are INSANE
 
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