Alright so I have the Muncie SM465 (4 speed with granny no O.D.) and have been thinking of swapping to a nv4500 (granny gear with O.D.)

I was wondering if anyone is running the nv4500 behind their 6.2 in a pick up single cab, if so what kind of millage are you getting highway?
I'm getting 17 with the Muncie and the pump turned up.

Also is there any way to identify the rear axle gearing? my granny gear seems to run out around 5mph, first 15mph. I think its 4.10 gearing but can anyone help me confirm?

Thanks -Kory!

I had a '97 3500HD that had a 6.5TD and a NV4500 and it was great truck. It got around 18mph, but it was 9,600# dump truck. Here's the comparison of mph and rpm with 4.10 gears figured on a 31" tire. The SM465 is on top and the NV4500 is on bottom.

 

Sounds close to my blazer's gearing. I've got 3.08s in my blazer and the SM465, which doesn't sound right at all for your truck, with it being a K20.

Is the engine screaming at ~60 mph? Mine's spinning 2,000 rpm at 60 mph.

I suppose you could have 3.73s in that. My 96 2500HD has 3.73s in it.

 

Let's try that again!

 

So i guess the better question to ask would be whats the other gear ratio listings for the other nv4500, (later or newer) im not sure which one you posted but just the numbers will work now that i learned about this kickass gear ratio chart!!! oh also what is the recommended rpm of a 6.2.

Sorry for being so slow on getting the specs right i have been busy and its been hard to fallow every update!

 

I had swapped out the n/p 4 speed for the n/v 4500 in the 91 that I just sold. By far the Best upgrade I had done to that unit.
The truck had 4.10 gears with the 4 speed it reved 2700 @ 100 kph !!! after the swap 2000 @ 100 kph. Mileage came way up , On summer fuel ,using cruise, all highway miles ,could get over 1100 km's from 115 or so litres of fuel. with 265-75 tire


It had a real sweet spot around 120 k

If you do change over you will need the bell housing from the n/v 4500 the bolt pattern is different than what you have !!!! trust me I know !!!!!

 

To check rear gearing jack the rear end up with tranny in neutral. put a mark on the driveshaft and spin the tire. If both tires spin the same way just count the # turns of the driveshaft for one turn of the wheel. 3 turns equals 3.08 gears, 3 1/2 turns =3.4? 3 3/4= 3.73, 4= 4.10, 4 1/2 = 4.5?. If the wheels spin oppositely count the turns and multiply by 2. 1 1/2 turns =3.08, 1 3/4 = 3.4? etc...

 

To check rear gearing jack the rear end up with tranny in neutral. put a mark on the driveshaft and spin the tire. If both tires spin the same way just count the # turns of the driveshaft for one turn of the wheel. 3 turns equals 3.08 gears, 3 1/2 turns =3.4? 3 3/4= 3.73, 4= 4.10, 4 1/2 = 4.5?. If the wheels spin oppositely count the turns and multiply by 2. 1 1/2 turns =3.08, 1 3/4 = 3.4? etc...

Close, but only jack up one wheel. Turn the wheel in the air one complete revolution and count the number of times the driveline turns, multiply by 2. You are going to either have 3.73 or 4.10 Most sm465 trucks had 3.73 and the 700r4 trucks mostly came with 4.10 in the 2500 series.

 

Thanks guys! I knew you would have some good info on this, ill check my gearing when i get home. with the 5 speed the gearing should be a lot better, (i wont have to go from 2nd to 3rd and bogggg so much on a hill

 

i know how you feel on that bog zone. between 2nd and 3rd on my NP833 transmission has a dead zone unless you rev the nuts outa the engine then drop to 3rd then its happy. really these motors shoulda had a 6 speed from factory to compinsate for the lower power output.

 

to figure out gearing its alot simpler then jacking the ass end up and turning the tires (almost everyone gets this way wrong). check the bolts holding the rear axle cover on, should be a tag with the info on it that will tell you what gearing you have and it will tell you if its an open or limited slip diff.


also you could remove the rear cover (this is the best and only sure way to get the gearing) and count the ring gear and pinion teeth then divide. alot of the time the ring gear will also have it stamped on it.

 

to figure out gearing its alot simpler then jacking the ass end up and turning the tires (almost everyone gets this way wrong). check the bolts holding the rear axle cover on, should be a tag with the info on it that will tell you what gearing you have and it will tell you if its an open or limited slip diff.


.

i have never run into this on a gm fullsize vehicle. and thats a lot of vehicles and a lot of years. same as the old story to check for a code stamped on the diff. its either in the rpo code, figure it out by turning wheels or open it up

 

Try this page if you put in your VIN it will list all the option etc

http://www.compnine.com/

 

I had an 85 (2wd) 6.2 liter that I put in the NV4500 with 3.08 rear end. (sold it last summer).

It would get on average around town 20.5 mpg. On the highway my high was 26mpg with the average being closer to 22.

 

theyre updating it right now or id try too

 

ah 6 speed would be nice.... I really wish Chevy would have paid Detroit more money to develop these engines and maybe they would have made the engine more durable to handle high boost.

 

did you know that general motors owned detroit diesel when they built the 6.2l?

 

that or gotten smart and teamed up with deere and got a real 6 cylinder rattling between the frame rails

 

Tell me about it, Have a huge Yanmar TDI. Or even a 2 stroke Detroit woulda been bad ass.

So If Gm owned Detroit at the time they must not have owned it a few years earlier when they made the 5.7 diesel.

 

"Try this page if you put in your VIN it will list all the option etc

http://www.compnine.com/"



Well that's certainly handy!!!
4.10 gears huh? no wonder she howls at 120kph

 

These motors are becoming available used, already the Navistar version is ten years old....

 

The Navistar is a nice upgrade on the regular 6.5's, but even it is not comparable to the P400. I have a Navistar 6.5 with a spun main bearing, and I have been trying to decide if I want to spend the money to have align bored, or just wait a while and try to score a P400.

 

GM always owned Detroit until the 90's. The early Detroits weren't even called Detroits, they were actually called GM Diesels.

 

i noticed that a 6-71 in a 8020 deere and a 2-something in a 435 deere both had a big GM cast into their supercharger housings right out in plain site

 

Hmmm.... Im not sure on this but didn't detroit have better engines at the time than the 6.2

 

Well, yes and no. Detroit was transitioning away from the 2 stroke diesels that were their mainstay for 40+ years, and the 8.2 as their first first venture into the 4 stroke market. The 8.2's were OK engines (when they got the head bolt problem of the early ones fixed) , but they weren't nearly as good as the 2 strokes, and like the 6.2's, weren't know for a lot of power. The highest HP version was a 230HP. The 6.2 used a lot of the technology from the 8.2 and like the 8.2, it was built with ecomony in mind.

 

we have gotten off topic a little bit... when im shopping for the nv4500 what kind of options am i looking for, i know ill end up converting to hydro clutch but i suppose these are the fallowing options.... 4 BOLT TOP OR BOTTELNECK TOP AND INTERNAL SLAVE CYLINDER OR EXTERNAL THROW OUT BEARING AND FORK

 

Get one with a external slave much nicer if you have to work on it (bleeding etc.) Those internal ones are the sh*ts to work on if you have any problems you are pulling the trans out to repair/replace . If you find a set up make sure the pivot ball (where the fork pivots) in bell housing is in good shape and make sure that the grease nipple is clear of old grease etc.

Also I like to use the bushing not the brg style pilot . I have found that brg. wears out the end of the imput shaft. napa still has the bushing and make sure to soak it in oil before you install.

If you need pics of one I have a complete set up trans and all (4500 external slave) out of the 94 that I took the engine from for the 98

 

Pictures would be nice!

 

the early nv4500's had a 6.34 first gear, the later ones were something like 5.61. The early ones are hard to find parts for, input drive gears and counter shafts. The late model transmissions can swap most parts with the dodge version with the exception of reverse.

 

yeah i knew they were built with economy in mind... what model was the 230 HP 6.2? im guessing military issue.

Thanks for the gear specs, do you know of any charts i can compare the muncie with the later nv4500 and the newer nv4500?

 

It is the 8.2L (fuel pincher) that had the 230hp, not a 6.2L.......

 

The early and late NV 4500's use different bellhousings also, early used external slave cyl, late used internal slave cyl, different bolt pattern also. Keep that in mind when shopping for a trans, best to find a donner vehicle to get all needed parts from. I did a conversion from a muncie 4 spd w/ creeper 1st. gear on a '91 6.2L and got a solid 7 mpg increase, Had a 34 gal tank and could drive it 650 miles between fill ups, real close to empty though.

 

wow nice, i learned today i have 3.72 gears in the rear end

 

I try to keep things OUT of my rear end...gears sound painful.