Engine/Transmission (1994 - 1998) 6 speed in a '97 2WD

[ewcmr2]

Last weekend when leaving Wendover UT towing at 19630lbs GCW I lost 5th gear. Drove the 500+ miles home in 4th at 62 mph (mileage at 62 in 4th = 14mpg, 75mph in 5th = 11mpg, speed really kills mileage when towing an extra tall GN race trailer!).



Pulled the rear section off the transmission yesturday to see what it looked like inside. I was hoping that I could install the updated nut and buy some time, but no such luck, the splines are almost all gone from the shaft.



Shearching both here and the web it seems that a nv5600 6-speed will go into a 24 valve and a 4wd 12 valver without much trouble. I haven't seen any info if this is also doable to a 12 valve 2wd. Someone posted the lack of a speedo pickup hole in the nv5600.



Has anyone put a 5600 into an earlier 2wd truck?



I plan on calling vendors tomorrow.



Thanks, Eric

 

[JohnE]

Contact Blumenthal's first.

After that, good luck finding a good installer.

 

[Joseph Donnelly]

The 6 speed swap is time consuming and costly. When your problem is nothing more than the common 5th gear problem, I suggest you call 800-std-tran tomorrow and see about getting either the 5th gear/mainshaft kit, or an exchange rebuilt NV4500 from them. My 5 speed has numerous parts in it from them, and has held up fine (I got it as a basket case to exchange into my Ram).

 

[ewcmr2]

There are a few reasons why I am thinking that a new transmission is probably the way to go in this particular truck.



First, this is apparently not the first time the 5th gear nut has spun off. The nut I took off has a set screw. The main shaft, which now has no splines, shows signs of the 5th gear nut having been *welded on* in the past.



Second, the second gear synchros seem to be going (which is probably fair, given 220K miles on this transmission).



Third, I've heard that the reverse gear in the 6 speeds is a lower ratio, and that would be really very nice. I back a 36 foot trailer into its parking space way down my driveway.



Fourth, since about all I do with this truck is tow, having more closely spaced forward gears would be a good thing.



I replaced the automatic transmission in my '96 twice, and I understand this conversion is more work than that. I guess if I'm going to be installing a new transmission, I'd rather have the transmission that seems better for my use. The biggest hold up seems to be whether or not you can have a working speedo in a 12 valve, 2wd truck with the 6 speed.



EC

 

[Boomer II]

Look here.

http://www.drivetrain.com/nv5600.html#NV5600-4WD 1994-1997

 

[ewcmr2]

I made calls to a number of TDR advertisers (Blumethals, Enterprise, Standard Trans&gear, and drivetrain.com) to check the feasibility of installing a NV5600 into a 2wd 12 valve.



The 6 speed does not have a port for the speedo drive.



For Cruise control and the speedo to work you will have to go with a 4wd transmission and buy a transfer case along with the rest of the conversion stuff. Or custom build some sort of tone ring/HALL effect pickup.



I don't have time to do all this so I'll be getting a rebuilt NV4500.



Thanks for the ideas, someday if find a wrecked 4x4 6-speed maybe I'll make the swap.



Eric

 

[JohnE]

Eric;



Did not know about the speedo drive issue on 2wd.

A friend just converted his 96 4x4 5 spd to a 6 spd for the extra forward gear especially between 3rd & 4th and the added reliability.

Possible adding a governor spring kit will give the engine extra rpm to fill the 5spd gaps?

Have considered adding a US Gear or Gear Vendors unit?



-John

 

[ewcmr2]

The governor spring idea is a good one. The 1000 rpm drop between 3rd and 4th isn't much fun when towing near max GCWR. Looking at Fritz's website running it up to 3000rpm's in 3rd would drop it back to 1800 going into 4th. Sounds much better than the current 2500rpm to 1500rpm drop.



Or I could go beyond the 230/605 power level



Eric

 

[JohnE]

beyond 230/605 ? What is holding you back?

Well, trany upgrade means a clutch, too?

The governor springs just makes the truck much more driver friendly. Sure **** ,uh jerks the chain of the other diesel brand driver's though.

 

[Turbo Tim 1]

FYI, just saw a 5 spd from a 97 in the classifieds for $1000, low miles

 

[ewcmr2]

Originally posted by JohnE

beyond 230/605 ? What is holding you back?

His wife--who wasn't happy with the "not legal for street use" on higher rated TST plates... :-{}



mlc

(the wife who fears CARB... besides, I pass all kinds of folks going up the Grapevine on I5 already... )



P. S. The clutch is on the way