6 speed swap

[Army12Valves]

Need info or links to previous threads or websites.

I've heard it's as simple as changing the 205 input shaft, and changing mounts. I need good solid advice and tech data, I will be doing this within the next month.

 

[RSchwarzli]

What 6 speed? 5600 or G56?

 

[Shadrach]

Read this https://www.turbodieselregister.com...-forum-1989-1993/192362-1st-gen-g56-swap.html You don't have to change the shaft at all. The transfer case bolts right up. Give us details about your truck and what you want to do please. Shadrach

 

[Army12Valves]

1992 W250, reg cab long box needs paint but mint other than that. 345,780mi as of now, has rebuilt pump, south bend clutch, 4 wheel disc brakes, doing a 4" lift to clear slightly taller tires, got the Getrag 5 in it with 3. 54s, I just want another gear, she doesn't like going over 65 MPH

 

[HBarlow]

Swapping the five speed for a six speed manual will not improve top speed or cause the truck to run more comfortably at higher highway speeds.

Top gear ratio of a manual six speed is not very different from a manual five speed.

I have never owned and don't know anything about them but I remember test driving a new '94 on a dealer's lot many years ago. I did not like the rev limiter and didn't buy one then.

My guess is the issue you are dealing with is one, it's your first diesel and two, the old 12 valves in factory stock condition did not like to rev much beyond 2400 rpm.

If the truck has 3. 54 gears as you stated extending the engines rpm range would probably give you more satisfaction. The 12 valve experts can tell you how to do that. I think it is relatively simple and inexpensive to do but I can't tell you how.

 

[NIsaacs]

Are you sure the gears are 3. 54's? If it feels like 65 mph is pushing it, I would say you have 4. 10's. With my '91 and 3. 54's, 75 mph is 2100 rpm. Like Harvey said, the six speed will not help your top end, however it does have yummy splits. The Getrag is a good transmission, so if it is not giving trouble you might want to just leave it alone. A six speed is an awesome upgrade tho, so don't listen to me



Nick

 

[Army12Valves]

This is my 4th Cummins, 2nd 1st gen, at 65 I'm not at 2400 rpm the truck will go into the 90s but it doesn't like cruising at those speeds. I want to cruise at 75+ like my 93 did without having to put 38" tires on it.



As you know the Getrag 1st is a low creeper that gives you only 4 road gears. The Getrag is definetly NOT an awesome transmission, it's far better than any AT but I've had problems with both of mine. I had an 01 with a 6 speed in it and I loved the way it drove. I really want the gears ranged closer and more of them. It is definetly 3. 54s I've had the diff open. I am doing a 4" lift and I'm trying to find some 33x10/35x10 or skinnier. Everyone in Columbus GA won't stock tall skinny tires. Does Michelein make a 265/85R16?

 

[Bob Beauchaine]

Additional power and RPMs out of the VE 1st gen IP is relatively easy and inexpensive to accomplish. Add a 3200GSK, an aftermarket fuel "pin", some pump tweaks and you are off and running.



As for the '94s & 95s their P7100 were not the best preforming P7100 out there, but they could also be set up for better performance.



The "rev limiter" Harvey refers to is actually the governor. These, on both the VE and the P7100, will change the point at which the IP begins to defuel.



The VE in stock form will start to defuel between 2400 and 2500 rpms. With the 3200GSK that goes up to about 3200 rpms.



Bob

 

[Army12Valves]

I've already tweaked my pump to where I want it. I don't want to sacrifice fuel milage, and I don't really need more power, I need more top end speed and closer gears. Working on taller tires already. I had my pump cranked up and it hauled but it wasn't worth the fuel milage loss and gained no additional top end speed.

 

[therabbittree]

swap some 3. 07 axles in it. . I run them and can cruise well into triple digits if needed . . I normally only use 5th gear if im over 60 mph. I use 1st gear every time I start and use 4th to tow and can tow in 4th nicely at 65 mph etc... I plow in low range and use low range to back up heavy loads. . works well for me... good luck

Deo

 

[Army12Valves]

I will be going to 3. 07s soon my rear axle bearings are begining to howl

 

["Mad Max"]

here's a link to a thread I did a while back, more or less same subject - might help some. I've still yet to do the swap, but it's on deck soon as I get the proper opportunity.



https://www.turbodieselregister.com...gen-nv4500-4x4-dually-conversion-upgrade.html



- Sam

 

[HHhuntitall]

... . as for a taller, skinny, tire, try 255/85R16(33x10. 00X16). They're a little hard to find, but BFGoodrich, Cooper, Toyo, and a few foreign tires are still made in it. Maxxis, Big-O, and BCT are a few. At one time they were the most common upgrade tire for Jeeps, Range Rovers, and the like. I know of no 35" tires narrower than 12. 50" in 16". I will say, I like the 315/75R16 (35x12. 50x16). That size has awesome flotation, great ride characteristics, and really help with gearing. Turning in the 1st gens is an issue with the 315s, as they can hit the springs pretty easy, and without enough lift, they can get into the rear fender some. The 315s'll also rub on the stock steering arm at full lock to the right.