Adaptor plate for gm bellhousing?

[KMott]

I am currently in the starting stages of a buildup of a 1986 gmc sierra k2500 4x4. I will be using a 6BT 1st gen cummins from a 91 dodge ram.

I am planning to use a GM SM465 4spd manual transmission with a 205t-case. My main concern with this will be adapting the cummins engine to the gm bellhousing. Im thinking if the cummins flywheel sticks out further from the bellhousing mounting surface than on a gm engine, i will have room for an adaptor plate, otherwise, i may have to install a lengthened trans. input shaft. My plan is to drill the cummins flywheel to take a gm 12inch clutch and machine a plate to adapt the cummins to the sm465. Has anyone tried this before, or know if there is a source for a plate like this?

Thanks, kevin

 

[CKnoop]

all you need is a cummins GM adaptor to bolt to the back of the 6bt and a cummins GM fly wheel you can get them from cummins not cheep. or find used. the adaptor from a 4bt will also fit the 6bt I can get the part # for the adaptor from work have a brand new one on the bench still waiting on the flywheel cknoop

 

[CKnoop]

GM adaptor plate part # 3916101 $629. 72

 

[DKarvwnaris]

Call Kenny at Autoworld, in Great Falls, Montana (406) 727 8915. I traded the last adapter set I had with them awhile back. It was a 4bt bellhousing adapter to GM along with the Starter and Flywheel. These adapters will clock the engine off level by about 5 to 10 degrees from the transmission.

You'll have nearly $2000. 00 in the adapter, flywheel, and starter if you have to buy the parts new. Personally, I'd go with a GM nv-4500 and switch the input shaft over to allow for the Dodge clutch, you'll have a much more driveable truck at highway speeds.

 

[KMott]

i would like to go with the sm465, just because of its durablilty and availability. Im going to be running fairly big tires, and top speed is not a big issue. I have a 1976 gmc 4x4 1 ton military truck im looking at next weekend.

Wouldnt it be possible to drill the regular cummins flywheel to take the gm clutch? I work at a machine shop, and i dont think that would be a big issue. But on the other hand, if the size is different (thickness) it may not work with the adaptor plate. Thanks again

 

[DKarvwnaris]

Unless you have torn down a 465 alongside a nv-4500, you will not understand how weak a 465 is in comparison to the 5 speed. Go to any parts store in your area and ask them to pull a clutch for gm 465 and a dodge diesel nv-4500. The input shaft diameter will show right off the bat what the rest of the transmission will be like. If you're running big tires, that take care of the need for an ovedrive, but not the torque of 5. 9 spinning against the smal diameter GM clutch. Why you would want to adapt a Dodge flywheel to take a GM clutch assembly makes no sense to me, the entire advantage to the dodge clutch is the overal diameter of the clutch surface being more resilient to clutch failure. This is especially important with big tires, tall gears, and a turned up injection pump.

If you work at a machine shop, then re-mill the mounting holes on a Dodge bellhousing to take the GM transmission and upgrade the input the shaft to a larger diameter/spline count.

This is all I can offer you as this is something I have explained in the past too many times. Don't want to convince you otherwise if you are set on this setup, trial and error are the best teacher for things like this. The cost of the Cummins adapters for the GM parts are reason alone for me to scrap the 465 or sell it to a Jeep freak who wants a nice readily available manual for rock crawling/log road use etc with no need for overdrive.

Good luck with it, hope it serves you well It will be a fun project no matter which way you go.

 

[KMott]

Hey, i appreciate your opinion. I am just in the beginning stages, and if im starting off wrong im glad to know now. I used to have an 86chevy with the sm465, and it was original with over 400, 000 km of hard abuse. I just assumed it would hold up well. Im planning on pushing a lot of power through this motor, and dont want to be limited by the transmission like with my 94 auto ram. Are you saying the gm nv4500 can handle a lot?



One of my concerns is being able to use a 205 transfer case with the setup. I just want to make sure i fully understand the setup you are suggesting. I use the gm nv4500, and install the dodge input shaft to take the dodge clutch, and run the original cummins flywheel and starter. And as far as adapting the gm nv 4500 to the dodge bellhousing, i will just have to relocate the mouting holes. I guess i would also have to use the hydraulics off a dodge as well.

If im understanding it right, i think its a great idea. It would surely save a lot of money, and would be nice to have the 5 speed. The only reason why i wanted to go with the sm465, was because i thought it would hold up better. I have read so much about the dodge nv4500 having problems, that i thought they were junk. Or maybe its just the huge torque of the cummins...

Thank for your time and ideas, kevin

 

[DKarvwnaris]

The NV-4500's are having problems because the stupid owners are pulling the guts out of them in overdrive. The 5th gear nuts are coming loose from the torque, it can be easily fixed in a 4wd model NV-4500.

A GM NV 4500 transmission can bolted directly up to the dodge bellhousing, the front holes are identical on both GM and Dodge, the difference is the input shaft, which is a bolt in swap through Kenny at Autoworld 406-727-8915. He can also get you all the parts you need to go with the hydraulic clutch using GM components for a neat bolt in parts list. (his old Chevy crew cab has a 5. 9 inline pumped/innercooled engine in it, along with the Dodge transmission). His is a 2wd dually, not 4wd, but that's not an issue.

If you go with a dodge transmission, I have a dodge 205 transfer case that will bolt right in with just a spline coupler adapter. I have it for a spare for my Jeep project, so its nothing I have to sell, but everything is for sale for the right price.

The GM NV-4500 will work with the GM 205 case if I remember right, check with kenny. Just remember everything about the dodge diesel driveline parts are heavier than anything GM ever produced one way or another, shafts, bearings, Yokes etc.

If you go with the Dodge clutch setup, let me know, I'll be happy to give you tips. Kenny will help you out too if you at least buy some parts from him. His motor mounts are the strongest and highest quality I've seen yet. I won't even bother building them for what he sells them for, its worth it, trust me on that one

Search out the posts on here for their username: "autoworld" and view their other customer's projects. You'll be impressed with their quality, I promise.



Kenny was going to prototype a GM bellhousing adapter to allow for use of a Dodge clutch, flywheel, starter with a paralleled engine mount pattern,(No off clocked engine to transmission degree like the Cummins adapter is) I haven't heard from them whether they did anything past the prototyped parts He had fabricated last time I was back home in Great Falls. I traded the bellhousing adapter parts I had off my 4bt for some other parts, that's what was used to reference the bellhousing adapter pieces. They are dead on CNC scanned bolt ups for the original with the exception of the clocking.

 

[KMott]

Thanks again for the great info. I won the military truck off ebay tonight, so ill be picking it up this weekend, and can go from there. Ill defintalely be giving autoworld a call once i get rolling on this thing. Ill keep you updated. thanks, kevin

 

[SOswalt]

Just so you know the first gen Chevy NV4500 won't bolt up to a Cummins bellhousing,94-95 had a different bolt pattern . In 96 all Gm,and Dodge were the same.

The Gm nv4500 will bolt to a Np205 t-case as long as it's has a 6 bolt pattern mounting flange.



Also the first gen Cummins engine flexplate/flywheel housing plate will not work with a Nv4500,you have to use a second gen housing.

 

[DogDiesel]

Say what?

BH pattern differences? This is ironic, since I have had both the 1st and second generation transmissions in my GM truck with the same GM BH, then when converted to cummins, both the same pattern with my GM adapter. While the shifter top style is different, the BH bolt pattern seems the same. I chose the 2d generation, because, with load, I like to use #1 for starting trailers, and the 1st generation Chevy was so low, it was useless for on road. I hear off roaders love it for crawling.

I did all the work, so it seems strange I missed the part about BH pattern differences. While I was using GM BH, any difference would surface the same, wouldn't it? Did I miss something?

All along, thru all New Vendors XMSSNs, I thought the difference in all trannys has been early GM lower # 1, different input shaft sizes, and 96 the spit year for top cover shifter GM set ups. While BH are different, I thought XMSSN to BH pattern was the same for all.

Are you sure of this fact, first-hand, or is was it told to you?



Wayne



I had a builder attempt to tell me that the Dodge NV4500 was larger, with larger internals, than the GM diesel NV4500. He believed he was telling the facts, and he build them for a living. He was mixing the GM gasser NV45000 and the Dodge diesel NV4500. Put two diesel XMSSNs side by side, and the difference was IP shaft size, in some models, OP teeth on some models and shifter same for all dodge, and split in 95/96 for GM.

Since I pull trailers a lot, I am getting way too familiar with this transmission.

Again, are you sure?

Just so you know the first gen Chevy NV4500 won't bolt up to a Cummins bellhousing,94-95 had a different bolt pattern . In 96 all Gm,and Dodge were the same.

The Gm nv4500 will bolt to a Np205 t-case as long as it's has a 6 bolt pattern mounting flange.



Also the first gen Cummins engine flexplate/flywheel housing plate will not work with a Nv4500,you have to use a second gen housing.

 

[DogDiesel]

Say what?

XMSSN to BH pattern differences? This is ironic, since I have had both the 1st and second generation transmissions in my GM truck with the same GM BH, then when converted to cummins, both the same pattern with my GM adapter. While the shifter top style is different, the BH bolt pattern seems the same. I chose the 2d generation, because, with load, I like to use #1 for starting trailers, and the 1st generation Chevy was so low, it was useless for on road. I hear off roaders love it for crawling.

I did all the work, so it seems strange I missed the part about BH pattern differences. While I was using GM BH, any difference would surface the same, wouldn't it? Did I miss something?

All along, thru all New Vendors XMSSNs, I thought the difference in all trannys has been early GM lower # 1, different input shaft sizes, and 96 the spit year for top cover shifter GM set ups. While BH are different, I thought XMSSN to BH pattern was the same for all.

Are you sure of this fact, first-hand, or is was it told to you?



Wayne



I had a builder attempt to tell me that the Dodge NV4500 was larger, with larger internals, than the GM diesel NV4500. He believed he was telling the facts, and he build them for a living. He was mixing the GM gasser NV45000 and the Dodge diesel NV4500. Put two diesel XMSSNs side by side, and the difference was IP shaft size, in some models, OP teeth on some models and shifter same for all dodge, and split in 95/96 for GM.

Since I pull trailers a lot, I am getting way too familiar with this transmission.

Again, are you sure?

Just so you know the first gen Chevy NV4500 won't bolt up to a Cummins bellhousing,94-95 had a different bolt pattern . In 96 all Gm,and Dodge were the same.

The Gm nv4500 will bolt to a Np205 t-case as long as it's has a 6 bolt pattern mounting flange.



Also the first gen Cummins engine flexplate/flywheel housing plate will not work with a Nv4500,you have to use a second gen housing.

 

[PKirby]

The 93-95 GM bolt pattern is different from the 96-up. The 96-up GM pattern is the same as Dodge. I have both in my shop. I use the early GM output shaft and tailhousing in the later Dodge transmission for my truck.

The GM output is smaller and not supposed to be as strong as the Dodge so I hope it holds up.



high-impact.net has some good info.



http://www.high-impact.net/transmission_and_gear/nv4500.htm



quote from High Impact:

Bellhousing Bolt Pattern:

GM 1993-1995 10. 078 across the top, 10. 394 across the bottom, 4. 685 vertically



GM 1996 + up 10. 078 across the top, 9. 738 across the bottom, 6. 043 vertically



Dodge (All) 10. 078 across the top, 9. 738 across the bottom, 6. 043 vertically

 

[SOswalt]

XMSSN to BH pattern differences? This is ironic, since I have had both the 1st and second generation transmissions in my GM truck with the same GM BH, then when converted to cummins, both the same pattern with my GM adapter. While the shifter top style is different, the BH bolt pattern seems the same. I chose the 2d generation, because, with load, I like to use #1 for starting trailers, and the 1st generation Chevy was so low, it was useless for on road. I hear off roaders love it for crawling.

I did all the work, so it seems strange I missed the part about BH pattern differences. While I was using GM BH, any difference would surface the same, wouldn't it? Did I miss something?

All along, thru all New Vendors XMSSNs, I thought the difference in all trannys has been early GM lower # 1, different input shaft sizes, and 96 the spit year for top cover shifter GM set ups. While BH are different, I thought XMSSN to BH pattern was the same for all.

Are you sure of this fact, first-hand, or is was it told to you?



Wayne



I had a builder attempt to tell me that the Dodge NV4500 was larger, with larger internals, than the GM diesel NV4500. He believed he was telling the facts, and he build them for a living. He was mixing the GM gasser NV45000 and the Dodge diesel NV4500. Put two diesel XMSSNs side by side, and the difference was IP shaft size, in some models, OP teeth on some models and shifter same for all dodge, and split in 95/96 for GM.

Since I pull trailers a lot, I am getting way too familiar with this transmission.

Again, are you sure?

Yes,

I know they are different for a fact!!!!! I have both of them to prove it,that they won't bolt up. I checked with GM to Make sure as well,they are different.



The spacing that* PKirby * list is the same info I got from GM.

 

[DogDiesel]

Amazing

I removed a 93 GM NV4500 and installed a 96 or later GM NV4500. Same bell-housing. How unusual it bolted up. Same bell-housing.



Bolted right up to transfer also.

Wayne

 

[SOswalt]

I removed a 93 GM NV4500 and installed a 96 or later GM NV4500. Same bell-housing. How unusual it bolted up. Same bell-housing.



Bolted right up to transfer also.

Wayne

Well I guess GM and 5 other major manual trans company's were all wrong!!!

Do ya think maybe you don't have a 93 Nv4500,did ya check the numbers or are ya just posting BS????

 

[DogDiesel]

SOswalt,

My truck is a 93, and I assume it had a 93 NV4500 since new and I did purchase my truck before 1996. I ordered my replacement NV4500 from Phoenix Transmission by 1-800. Gave them info on truck and informed them I wanted the 96 later GM 1st gear. There was no provocation that a modified NV4500 would be shipped. It arrived within a few days. Later, I upgraded that NV4500 with a 96 and later NV4500 with the later style top cover, which is a so much smoother shifting transmission. You'll notice that in all my postings, I am asking questions on this topic, versus stating that I knew I was right, using comments like "this is ironic or unusual, that it should have been obvious. " I did my own install, but I was not present for the transmission build. I guess it is hard sometimes in forums to see the distinct difference between questions and statement of fact, even when the poster uses statements suggesting unsurety, like "I thought--it seems strange--this is ironic, etc" but I will make an effort to simplify my postings to an easier reading level to avoid such confusion in the future.

Wayne

Well I guess GM and 5 other major manual trans company's were all wrong!!!

Do ya think maybe you don't have a 93 Nv4500,did ya check the numbers or are ya just posting BS????

Originally posted by DogDiesel:

BH pattern differences? This is ironic, since I have had both the 1st and second generation transmissions in my GM truck with the same GM BH, then when converted to cummins, both the same pattern with my GM adapter. While the shifter top style is different, the BH bolt pattern seems the same. I chose the 2d generation, because, with load, I like to use #1 for starting trailers, and the 1st generation Chevy was so low, it was useless for on road. I hear off roaders love it for crawling.

I did all the work, so it seems strange I missed the part about BH pattern differences. While I was using GM BH, any difference would surface the same, wouldn't it? Did I miss something?

 

[DKarvwnaris]

What was this thread about?, I forget now.



All the GM conversions I have done so far were primarily using a 6. 5 diesel GM nv-4500 transmission. The others had automatics that we sent to budweiser to send us more beer cans with :-laf (I do remember an issue with the GM gas nv-4500 models, but I recall it was in the input shaft match ups due to something with diameter or gear alignment, doesn't really matter, its a rare find to get stuck with one of these anyways)

I don't remember a difference in the front bolt pattern of the nv-4500's but that does not mean that GM has not done it. It would not surprise me if they did one bit. GM has always been self righteous when it comes to proprietary parts they buy being altered just enough to make them a non crossover to other vehicle makes/models with the same part components like axles, transmission's and minor general trim parts. It this kind of thinking that has prevented them from being a target from a foreign buy up (enter Renault, Nissan and uncontrollable laughter )