1994 chevy 2500 HD diff...

[84stealthranger]

my grandfarther has the a 94 2500 hd and it gets horrible gas mileage were thinking of swapin axles does anyone kno what gear ratios came with these trucks or what axle would be better its got a tool box bed on it like the work ones with side doors and top flip trays its a single cab with 350 and a hydromatic tranny i gotta look at what gears it has now where would i find the tag?

 

[JohnnyU]

In the glovebox. There should be a white tag with the RPO codes listed on it.

The rear axle ratio code should be a GU* or a GT* number. I'll post the codes when I get home later tonight.

 

[84stealthranger]

ok thanks

 

[Will]

If you are getting 14-16 highway, you are doing okay. That should have an overdrive and a rear gear swap isn't going to help it. If it has 3.73s and you swap in 3.42s the engine is going to open the throttle more on hills to get the torque back. Slowing the engine down isn't going to have an effect. I know you think it will, but it won't. It's not enough. The largest gain with autos was the lockup torque converter, and you should have that already.

It takes a certain amount of fuel to push that thing through the air at a given speed. There's nothing you can do to make it get good mileage, except swap in a 6.2 diesel--which will immediately bring you up to 22+mpg.

 

[Ozwynn]

check to see if the front axle is unlocked ......

It takes a certain amount of fuel to push that thing through the air at a given speed. There's nothing you can do to make it get good mileage, except swap in a 6.2 diesel--which will immediately bring you up to 22+mpg.

going to go pick up my 6.2 on Thursday...... much more durable block than the 6.5

 

[JohnnyU]

GU1: Axle rear, 2.41 ratio
GU2: Axle rear, 2.73 ratio
GU4: Axle rear, 3.08 ratio
GU5: Axle rear, 3.23 ratio
GU6: Axle rear, 3.42 ratio
GV1 : Axle rear, 2.73 ratio
GV2 : Axle rear, 5.83 ratio
GV3 : Axle rear, 3.08 ratio
GV4 : Axle rear, 3.36 ratio
GV5 : Axle rear, 3.55 ratio
GV7 : Axle rear, 4.11 ratio
GV8 : Axle rear, 2.72 ratio
GW2 : Axle rear, 2.56 ratio
GW3 : Axle rear, 2.56 ratio
GW4 : Axle rear, 3.31 ratio
GW5 : Axle rear, 2.73 ratio
GW6 : Axle rear, 3.27 ratio
GW8 : Axle rear, 4.10 ratio

 

[Will]

check to see if the front axle is unlocked ......




going to go pick up my 6.2 on Thursday...... much more durable block than the 6.5

These are the casting numbers for the blocks I know about. The number is on the rear of the block below the vacuum pump or whatever newer engines have there. An rpm sensor for the tranny controller I think.

6.2/6.5 Cylinder Blocks, info
-10149599 92-93 6.2/6.5—best block, no failures. I have one of these as a GoodWrench replacement and it spent 3 years towing for me with a Banks turbo. It's in my barn on a stand waiting for the 660 block in my trucl to fail. It may sit here forever.
-12552929—6.5
-10237141—6.5
-12555506—6.5
-14022660—82-91 6.2, supposedly crack-prone. My current truck has this. 6 years with 12psi of boost and frequent heavy towing. No failures, but I wouldn't be suprised if it is cracked and no worthy of being rebuilt. I don't expect it to fail anytime soon.

 

[Ozwynn]

thanks ..... I was looking for the casting number and couldn't find it ...... apparently not in the same spot as the 599 that was in my truck..... the block I picked up was a military take out....... he wasn't sure if it was taken from a Hmmwv during the 6.5 upgrade program or if it was pulled from a CUCV .......