NV4500 5spd Conversions - Diesel & Gas, 2WD & 4WD

Complete Conversion Packages

High Impact offers custom engineered conversion packages. Complete NV4500 installation packages are available for MANY vehicles. These include needed Bellhousing or adapter, any needed clutch components, transfer case adapters. Transmissions are custom configured with correct input/output shaft as is optimum for the application. 

The fine print: As for "is it 100% Bolt-in", yes, all the components should bolt together fine.  However, I would never consider or assume any installation of a transmission that did not come in the vehicle was going to be 100% bolt in:   1. Might work out that way. 2. Most cases have a few issues you will need to figure out on the fly. 3. Occasionally there is some issue we did not anticipate that turns out to be a hassle. That is rare. In any event, our customer service is always available to help you resolve whatever issues may arise in your conversion. Our Tech Support is generally quite a bit more knowledgeable than the average Joe you get on the line!

Turnkey system installation

We do NOT have a Jeep or 4x4 shop ourselves and do not work directly on customer vehicles. We do in many instances work with install shops, and even have several we have worked with a lot and can sub install work to for customers desiring our knowledge and engineering of the system while wanting a complete turnkey install done professionally.

    Recommendations regarding shops to do custom work for you

I want to make a general observation, and like all general observations, there will be exceptions. However: An Auto repair business and a custom fabrication or 4WD shop are two very different businesses. The repair business is involved in diagnosis and repair of stock vehicles. They quote and work jobs out of references such as MOTOR'S MANUAL. Custom 4x4 and fab shops specializing in doing things to vehicles that DID NOT come that way from the factory. I know, there are a lot of guys competent to do either, but rarely do I see one shop that operates efficiently or well doing one when it is set up primarily to do the other. 

thus: TAKE CUSTOM WORK TO A SHOP THAT MAKES IT THEIR PRIMARY BUSINESS TO DO CUSTOM WORK. If you cannot find the job listed in MOTOR'S MANUAL consider it custom work.

What is involved in an NV4500 conversion?

Generally speaking, when you purchase one of our engineered packages: You will be supplied with the primary ingredients to install a NV4500 in your vehicle. The following are the main items to consider:

Driveshaft modification: 

In many conversions, the overall length of the installed transmission will be different than the current transmission, resulting in the need to modify your driveshafts. If you measure the overall length of your drivetrain from the engine block back to the mounting surface of the transfer case (in 4WD vehicles) or the driveshaft yoke (in 2WD vehicles), it is then easy enough to add up the components of the NV4500 package to go in. (Bellhousing, BH adapter [if any], NV4500 main case, transfer case adapter [4wd] or 2WD tailhousing. From this you can determine accurately whether driveshaft modifications will be needed. Such driveshaft modifications can usually be performed by a local driveshaft shop. Typical cost of such mods are $2-250.

Crossmember/Skidplate

Crossmember location and/or modification: Most vehicles have a crossmember (or in some Jeeps, the skidplate) supports the rear of the driveline. It is usually located under the transmission tailhousing or 4WD transfer case adapter. (Some vehicles use  bellhousing as to frame mounts as a rear drivetrain support). In most cases the stock crossmember will work with some modification. You can get a pretty good idea of what is involved here by looking at your existing crossmember and comparing it to the following description of what an NV4500 likes to see: 

NV4500 crossmember is located about 14" from the front of the transmission (which on gas engines is about 7" from the rear of the engine block when using a Dodge input NV4500 or 6.5 inches when using a GM input NV4500). If yours will need to move, it is frequently possible to simply unbolt the crossmember, move it forward or back, re-drilling the frame at the desired location and bolting in place.

An NV4500 crossmember must pass below and be the transmission tailhousing or 4WD transfer case adapter. This tailhousing or adapter is then bolted to the crossmember via a rubber or urethane isolation mount. We have several different mount kits we supply in conversion packages to facilitate this.

In some popular conversions where they are useful, we offer crossmember/skidplate adapter kits and/or complete replacement crossmembers as a part of our conversion packages.

In most cases, skidplate equipped vehicles will simply need some minor drilling and such to mount the NV4500

IF your existing crossmember proves unsuitable, and a pre-fabricated replacement is not available,  you will need to fabricate a new crossmember. This generally involves cutting, welding and drilling steel tube, angle and/ or channel into a suitable shape, and bolting this into the vehicle. You will need suitable pieces of steel, a cut-off saw, electric drill and a welder. Estimate 2-3 hours to fabricate a crossmember.

Shifter Location and Stick Lever modifications

The shifter stick on an NV4500 comes up roughly 9.5" from the front of the transmission. There is a short stub on the transmission, and the shifter lever (extension handle) attaches to and is removable from that. 

Take a look at where your current shifter stick comes up. If the location is different, it  may prove to require a different location for the hole in the floorboards for the stick to come up through. If this is the case, It will be necessary to measure and cut a new hole in the floor in the appropriate location. The old hole may be patched using a piece of sheet metal cut to size to cover the old hole, and attached to the floor pan by sheet metal screws or pop rivets. We recommend using silicon sealant glue (RTV) to seal this and vibration-proof it.

Factory shifter sticks come in different lengths and shapes. Many transmissions had the shifter stick located forward on the transmission case. This necessitated snaking the shifter lever back out from under the dash, and then bending up. The NV4500 shifter will typically come up to the rear of the dash, in clear space. In any case, we supply a simple steel shifter stick that is easy to heat and re-bend if the shape does need to be changed. (Factory NV4500 sticks incorporate rubber in their design, and cannot be heated and reformed)

Back-Up Switch

All NV4500s are equipped with an electric back-up switch. This switch closes when the transmission is in reverse. If you desire to use this switch to operate back-up lights, you will need the correct connector-pigtail.  This part is GM PN 12085485 or 14014559 or AC Delco #PT107. The GM switch will fit the Dodge trans. TIP: When replacing a Getrag with an NV4500 on a Dodge Cummins, the Getrag b/u switch will fit the NV4500, and will thus still work with the existing electrical connector

A customer has advised me that wiring pigtails and kits to build compatible connectors are available from: Info:

 http://www.weatherpack.com

to Order: (from) LedFoote

Bellhousing and clutch:

The NV4500 has a bolt pattern that is unique to the NV4500. When converting from a different transmission, an adapter plate or replacement bellhousing will always be needed. In some cases the conversion is based around an adapter plate attached to a factory bellhousing (such as in Ford applications). In other cases a different bellhousing will be required (sometimes an off the shelf factory bellhousing is used, however in many cases a custom or an aftermarket "conversion" bellhousing will be used, making the job simpler and less costly. 

In some cases, both methods are available, and pros and cons can be weighed. The main advantage of the adapter plate method is that usually the stock clutch and clutch linkage can be retained as-is. The main advantage of the replacement bellhousing method is it will be 1" shorter (which matters really only in short wheelbase vehicles where every inch counts), or in the simple fact of having fewer parts in the stack up.

Clutch: As mentioned above, when using an adapter plate, the existing clutch and clutch linkage will usually work as-is. It is of course recommended to replace the clutch disc, pressure plate and throwout bearing if they are not fresh. In the case of a conversion bellhousing, in many cases the stock parts will still work. We have tried to mention in the specific packages whether stock components may be retained. Where stock components will not work, we have specified suitable replacements as part of the conversion package.

Hydraulic Clutch Linkages: Considerations putting later systems into older vehicles

Pilot Bearing: Our conversion packages will typically supply a replacement pilot bearing suitable for the conversion in question

2WD tailhousing/speedometer hookup

Our NV4500s can be supplied with several different output configurations. Depending on what is in your vehicle, and your requirements, one or the other may be superior. We will go over his with you at the time of purchase, and determine which is optimal. The possibilities include: 

6" Tailhousing with a fixed yoke (available configured for GM electronic vehicle speed sensor (VSS), or blank, for axle mounted VSS)

13" tailhousing with a slip-yoke (Available configured for mechanical speedo, electronic vehicle speed sensor (VSS), or blank, for axle mounted VSS)

notes: Mechanical speedo drive components needed:  Dodge Speedo Gear Applcations

4WD Adapter housing and output shaft

There are three factory configurations available. Depending on what transfer case  you desire to mate the NV4500 to, and what vehicle you are putting it all into, different configurations would be optimal. We will go over these factors with you at the time of purchase to determine what is optimal for YOUR conversion. General assumptions are made in the published packages, assuming stock Tcase for the vehicle in question. 

"No extra cost" Options include

Factory GM tailhousing with 32 spline output shaft

Factory Dodge tailhousing with 23 spline output shaft

Factory Dodge tailhousing with  29 spline output shaft

Extra Cost options include:

Aftermarket transfer case adapters (for use where a factory NV4500 setup will not work with your transfer case. We have a wide variety of these available. A full list can be found on the "4WD transmission - transfer case adapters" page.

Dodge style Cast Iron 4WD tailhousing: A direct replacement for the aluminum part used on Dodge transmissions.

Installation Difficulty Disclaimer:

While every attempt has been made to make this as straight forward a conversion as possible, please realize you are bolting a transmission into your vehicle that is other than than the one it came with. You must expect a certain amount of ingenuity and "make-it-fit" to be required. We realize this is part of any conversion: Our tech support is always available to go over any technically difficulties you may encounter. And you will find us to be considerably more knowledgeable than the usual joe you get on the line!

NV4500 Conversions in a Ford Truck

The package we use for that application will bolt the NV4500 to the stock Ford bellhousing via an adapter plate. The adapter plate is 1" thick. The NV4500 main case is 12.375" long. The tailhousing is 6.25", and the adapter to the Ford Tcase is 1.650". You could compare these numbers with the parts that are coming out. 

Conversions from an Automatic

Will entail all of the above general conversion information. In addition, you will need a flywheel and clutch components. If the package in question uses a bellhousing adapter plate, a Factor bellhousing will be needed. We have variations of all of our conversion packages to supply all of these components.

Clutch pedal and linkage:

In most cases it is easiest to bolt in the clutch linkage from your year and model truck with a stick trans. We can supply master and slave cylinders. The actual pedal assembly, and any mechanical linkages, are either dealer items (in later model trucks) or junkyard items. We have not found it practical to supply these items: These are pretty much the only parts you will be on your own with. In some cases it is practical to modify a pedal assembly out a different truck to work. Advance Adapters carry a line of generic clutch pedal assemblies that may work. These we can supply. In any event, we can discuss your specific application and make suggestions and include any parts we can supply into the package.

Hydraulic Clutch Linkages: Considerations putting later systems into older vehicles

Issues when converting from auto to stick on computer controlled vehicles

NV4500: General Information:

In 1992 Dodge and General Motors trucks started appearing in showrooms with one of the most versatile transmissions ever to be offered in a production truck: the New Venture Gear 4500. General Motors applications include it as an option in 3/4 and 1-ton full size trucks.  Dodge standard duty units come in trucks with the 5.2 and 5.9 liter engine, while Dodge HD versions are used with Cummins diesels and V10’s.

This transmission is a fully synchronized (except reverse on GM models) five-speed gearbox with all of the strength and low-gear benefits (and then some) of the older granny four-speeds, with a 27-percent overdrive. The cast iron case is combined with massive gear sets in an almost compact 200lb package. This unit shifts with a smooth, short action and very distinct shift gates. We consider it the premium manual trans swap for 4x4 vehicles.

Gear Ratios:

Current production Dodge NV4500 and GM NV4500 share the same gear ratios. Early GM units (93-94) were built with a lower first gear ratio of 6.34 to 1.0. These low-geared GM boxes have since been discontinued and are generally much more difficult to obtain. We are able to provide new and remanufactured NV4500s with these early gearsets.

Beginning in 95’, all GM units were built with the same gear ratios as the Dodge unit.

	GM 93-94	95/up GM; 93/up Dodge
First Gear	6.34	5.61
Second Gear	3.44	3.04
Third Gear	1.71	1.67
Fourth Gear	1.00	1.00
Fifth Gear	0.73	0.73
Reverse	6.34	5.61

Specifications

Dimensions

Bearing Retainer specification

Bearing Retainers:
GM 96-up, and all Dodge Std Duty retainer: GM retainer is for internal slave and dodge retainer is for ext slave, but they will both fit NV4500s GM 96-up, and ALL Dodge std duty
Dodge HD is a Different retainer.
GM 92-95 NV4500 uses a bearing retainer with a smaller outside diameter, and a smaller bolt circle, and is not interchangeable with the other NV4500s.

Bearing Race
All NV4500s use the same bearing race EXCEPT GM 96-up. This parts should be replaced when a new tapered roller bearing is installed.

Tapered Roller Bearing
All NV4500s use the same tapered roller bearing. When changing shafts, however it is extremely difficult to get this part off the old shaft without damage, and thus is generally replaced

Input Seal 
the input seal is the same on ALL NV4500s. This part sis hard to remove from one retainer and put in another and should be replaced when changing the retainer.

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

Shifter Stub Specification

The NV4500 shifter will have a short stub sticking up from the top cover, There are 3 different methods by which a shifter extension handle attaches:

Dodge NV4500 1993-1999   A short, square stub sticks up

Dodge NV4500 1999-up        Threaded stub, 12mm x 2.0 pitch threads

GM NV4500 (All)                      Threaded stub, 14mm x 1.5 pitch threads

Lubrication:
You MUST use the correct synthetic lubricant. The GM part no. for the correct oil is 12346190 (quart). The Dodge part number for the same oil is 4874459   Use of ANY other oil in the NV4500 will lead to failure and also voids any chance of a warranty claim.

We have this lubricant available.

Additional Info: Here is the response to an inquiry that was sent to Castrol USA about where to get Castrol Syntorq in Europe: "Castrol TAF-X 75W-90 GL-4 gear oil is made in the U.K. and sold only in Europe. However, the equivalent in the U.S. is Syntorq LT. Having said that, Syntorq LT SAE 75W-85, API GL -4 is a premium high performance, synthetic gear lubricant for synchronized manual transmissions. The all new "clean slate" approach enables Syntorq LT to provide consistent performance and durability under the most severe operating conditions due to its unique polymer free formula. It has been designed primarily as a problem solving gear lubricant for manual transmissions to provide reduced gearshift effort at low temperatures. Syntorq LT is available through General Motors (Part #12346190) and Chrysler (Part #4637579) dealerships. Please contact your local dealership." 

Swapping input shafts

In some conversions, a Dodge input shaft is used in a GM trans, or vice versa. When we supply the trans, it will come with the correct input shaft in it for the application. If you already have the trans, and need to change the input shaft, this is easily done from the front of the unit and Does NOT require major disassembly of the trans. It is recommended to check main shaft end play after the swap, incorrect endplay can cause premature trans failure. To check end play, use a magnetic base dial indicator, zero it in on the rear of the trans main (output) shaft. use a small pry-bar or screwdriver to move the mainshaft in and out of the trans, reading play on the dial indicator. Should be .002-.006

6.34 1st  Gear & 5.61 1st gear units

High Impact offers brand new NV4500 transmissions with either 6.34 ratio 1st gear or 5.61 ratio first gear.  For the first two years of production of these transmissions in General Motors vehicles, they were built with an extremely wide ratio 6.32 to one first gear.

While not as smoothly drivable on the road, the 6.34 ratio unit is in many cases the ultimate off-road off road manual trans. In vehicle using dual transfer cases or extreme underdrives, the 5.61 unit is generally better, as you don't need to squeeze that last little bit of low gear out of the trans

NOTE: The 6.34 ratio transmissions are available ONLY with the GM input shaft, and the early GM NV4500 bolt pattern. They are not interchangeable with the later GM or Dodge NV4500s. This is important to know as our bellhousing adapter plates must use the Dodge input shaft (it is longer). Therefore they MUST use either an early GM factory bellhousing, or several aftermarket full bellhousings we offer to use this transmission with AMC and GM engines. Conversions must be specifically designed for this transmission. We CAN supply them with GM or Dodge output housings/shaft. 

Custom Configurations

High Impact can provide New NV4500 transmissions available in GM/Dodge factory stock configurations, or custom configurations.  This means we can supply a brand new NV4500 with, say a Chevy input shaft, but with a 23 spline output shaft and the Dodge style tail housing.  Custom configurations in some cases lower the cost and complexity of a conversion because in some cases one configuration will mate better to the motor, but the another will mate up the the Tcase better.

Misc Tech Notes

Hydraulic Clutch Linkages: Considerations putting later systems into older vehicles:

Master cylinder: The easiest master cylinder to bolt in to your vehicle would be the one the one from YOUR year and model vehicle, it will fit a stock firewall and clutch pedal. There are potential problems here, however: The master cylinder must have a compatible fluid displacement with the slave, otherwise proper clutch travel may not be achieved. Also, late model parts have OEM specific fittings that the aftermarket custom hose shops do not seem to have, so custom hoses often involve cutting up two stock hoses and having them coupled. And some late model hoses are only available from the dealer, and as a PART of a COMPLETE assembly they will not break up. (Such as a master cyl-hose combo, where they will not sell you only the hose). In these cases we have found it easier to USE the OEM matched master-hose-slave combo, and modify the brackets to mount the master cyl to the firewall, and the modify the linkage rod as needed to the pedal to get the correct travel for the slave cyl. This way you know the hose fittings match up, and the master and slave are hydraulically matched. Our packages are generally engineered int he manner that is the closest to trouble free, although you are free to choose whatever method you prefer for your project.