NV4500 Buyer Beware

NV4500 Buyer Beware

gert

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I have found out the hard way buying a transmission that someone cobbled together..... there are differences in the NV4500 that makes somethings not interchangeable:


Early model GM 92-94 transmissions have a 6.34 first gear and a 6.34 reverse. The bolt pattern on the front is the same as a SM465, this bolt pattern is different than the 1995 and up. The Gear set will not be interchangeable with the latter case. The reason is in the reverse idler gear and counter shaft size necessitated a 2 3/8 long idler gear which changed the shape of the the case:

Early model Look at the protrusion behind the pto cover and compare it to below: (also notice early style cover/shifter style)

32054bb54d0c548c2_zpsrosbi39a.jpg

Late model 95 and up the protrusion is smaller to accommodate the shorter idler gear on the 5.61 reverse gear: (notice bolt on shifter like late model transmissions, the cover IS interchangeable between cases)

GM_2WD_11_zpswurnq9fd.jpg

this is what the early counter shaft and idler gear looks like, the counter shaft gear teeth do not go all the way the the back of the case to clear the main shaft reverse gear:

2012-07-04_13-56-48_106_zps5cjox6zw.jpg

Late model 95 and up: notice the full tooth counter shaft and shorter idler gear: ( notice the one piece counter shaft compared to the 2 piece pressed together early counter shaft)

IMG_20120707_113514_zpskpfilib9.jpg

this is what happens when you mix and match: I could not see this when I bought my transmission because the main shaft gears covered it up and of course it wouldn't spin I thought it was do to it not having the rear main bearing installed. The seller told me the 5th gear was burnt out and he decided not to rebuild it after it was at his transmission re builders shop.Well it was actually do to the idler gear crammed against the reverse gear:

IMG_3478_zpsmkcbi8hr.jpg

When you are shopping for an NV4500 know the differences. i hope you have better luck than me. I was specifically not looking for the 6.34 geared transmission. I simply measured the bolt pattern on the front of the trans and looked at the gears and overall condition of the trans and thought I had what I wanted a 5.61 geared Chevy input 2wd trans. well not was all as it seemed I found part of one anyway :mad:
 
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Thank you for the photos and write up gert - sucks you had to go through this...
 
Thank you for the photos and write up gert - sucks you had to go through this...



Yep I'm still pissed, I have a pretty 195 pound spare parts bucket at the moment. Next paycheck I'm going to start calling around and see if anyone has an early case to match my gears.


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Also going to find out how the two different Overdrive ratios work as well and will let you guys know that to


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I see Pete looking at this too - maybe we can get it in a tech sticky or something to get it more noticed for people searching for info before purchasing...
 
I think that would be helpful info to have for anyone researching these transmissions


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So the main difference in the early case is the extra room inside the housing to accomodate the longer idler gear which can be seen on the outside by looking at the driverside rear of the case. The protrusion should look like the case shown, notice the black line drawn on the case


IMG_3593_zpsjqvso8cz.jpg


the reason for the longer protrusion is to make room for the 2.375" long idler gear do to the low 6.34 reverse gear there are no teeth on the counter shaft at the back of the case


IMG_3594_zpsfw3fgum6.jpg

95 and up 5.61 gear case has a shorter protrusion to work with the shorter rverse idler gear

IMG_3597_zps4eyosrfv.jpg


Also the bolt pattern for the bellhousing is different. I plan to add the extra holes on my early case so that it will have both bolt patterns. I looked the cases over pretty good and it looks like the front faces are the same

IMG_3595_zps9kywghxw.jpgIMG_3596_zpsdha3siws.jpg
 
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stay tuned more to come, I am ordering my reverse gear this week and Bell housing kit from Advance Adapters. After that I will get my 5th gears and 5th gear nut to complete my rebuild :chug: 99 to 1 crawl ratio here I come :D
 
Set this thread as a sticky in the Drivetrain section - great write up bud

:chug:

:notworthy:
 
I got more coming for it when I can free up some more Jeep money, I wanna cover the difference in the 5th gear ratio and cover the Advance Adapters bell housing and double bolt pattern drilling I plan to do to my trans housing


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I see Pete looking at this too - maybe we can get it in a tech sticky or something to get it more noticed for people searching for info before purchasing...

Yeah you caught me looking. Great info. JR good job on the sticky. :chug:
 
Gert - Let me know when you're all complete and I may copy the relevant posts into a new thread named NV4500 versions and tech or something and stick it in another spot too. Once stuck in the tech section though it's not editable anymore (easily anyways) so we'll work together on that.

:chug:
 
Gert - Let me know when you're all complete and I may copy the relevant posts into a new thread named NV4500 versions and tech or something and stick it in another spot too. Once stuck in the tech section though it's not editable anymore (easily anyways) so we'll work together on that.



:chug:



Will do


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One thing no one has mentioned before this. One of my neighbors has a 92' GMC 4x4 truck that he bought new. He has 230,000 on the truck. Bad thing and here is what I'm thinking you should watch for, he has had to replace 3 of the aluminum bell housings on his NVG 4500. Now he does use his truck hard. Pulling things for his saw mill that he probably should not be!
 
Green with envy, I have not heard of bellhousings breaking on the NV before


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Been gone awhile, had a baby in the ICU and am still catching up from that. In the mean time the early reverse idler gear was discontinued. I made a few calls and to my amazement 2 different rebuilders on Craigslist said they had used gears. So I got to the police impound yard of all places as fast as I could and scooped up the last used part I need to complete the build of my trans so you can see the big difference in length between the two. The inside diameter is larger on the early style so the bearings won't interchange either. cd386e6b1149db710d8e944ce72d8116.jpgddf65b3faee3caacd6ea725315c01863.jpg


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Now to keep working overtime to get the rest of the parts to finish the build and get installed


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Welcome back gert, hope your baby is doing better.

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Green with envy, I have not heard of bellhousings breaking on the NV before


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Hopefully you little one is doing better. gert, this was what I saw with my own eyes. I also have read on one of the forums to watch for cracked bell housings!
 

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