drive train specs

[James68352]

where is a good site that outlines how to tell what axle diffs I have on the front and rear of my truck?

where is a good site that I can find the specs, namely the gear ratios, of my 3spd OD manual tranny?

what is the best RPM range for the 6.2? what is the max RPM for the 6.2 ?

Thanks

Jim :confused:

[BobND]

The axle gear ratio codes are in the member's area:

http://www.thedieselpage.com/members/rpocodes.htm

Here's a mileage link:

http://www.thedieselpage.com/mileage.htm

[Old6.2]

Jim, Our tranny ratios are 3.09, 1.67, 1.00 and .73 for OD. GM stopped installing these about 18 years ago and parts are getting harder to find.

[mpascino]

what type of trans was this and what kind of power ratings will it hold. Is it considered a truck trans. You have my mind wandering now.....

[James68352]

THANKS Old6.2,
Going by those numbers and using the rmpprog that I got from these forums that puts my rpm range like this:

2012rpm at 60mph with 4.10gears in OD with 30" tires

1512rpm at 60mph with 3.08gears in OD with 30" tires
2071rpm at 60mph with 3.08gears in 3rd with 30" tires

I am pretty sure I have the 3.08 gears in my axles right now because I don't bother with OD until the highway at speeds of 65 or better. Any lower speed and it's almost like lugging the motor. I am wanting to put in 4.10 gears in the axles because I primary use of this diesel is to pull a 5th wheel camper. I figure that with the 4.10gears I can still run the same tranny but treat it like a straight 4spd rather than an OD tranny. Now if I can find what the RPM ranges are for this motor it will give me a better idea of how things will work out over long distance.

Jim smile.gif

[Old6.2]

Our 4 speed is a New Process 833a and was used in Chrysler products (ie; Dodge Ramcharger) in the 60s and 70s as a straight 4 speed with a firt gear of apx. 4.50 to 1. The input shaft and input bearing holder was changed to GM specs for our trucks and you might be able to install your current GM input setup if you found a Chrysler box. This would give you a strong first gear for towing and cost much less than changing out two differentials. Please verify the above with a tranny shop before you invest!

[James68352]

Excellent idea about the tranny. I am going to check on it although I am concerned about the huge gap between 1st and 2nd gear in the config. I am still going to change the ring and pinions to also help with reverse. Backing the trailer now can sometimes be a dead end unless I put it in 4low. I had thought about in the far future maybe slipping a NV4500 in place of the NP833a to also help with the towing and better control of the power.

What is a good RPM to cruise the highway at? I don't want to have the motor wrapped tight just to cruise 65 pulling my 5th wheel.

Thanks for all the help!

Jim :D

[Old6.2]

I'm not sure what you mean by a huge gap in the gears as the 4 speed would have 2nd and 3rd gears between 1st and HI where our OD only has 2nd. My suggestion was a cost effective one by replacing the OD gearset within the same case and ALL original parts going back in. If you have the extra cash for a NV4500, mounting adapter and altering drive shaft lengths then that would be a better way to go.

[Dieselboy]

Originally posted by James68352:
What is a good RPM to cruise the highway at? I don't want to have the motor wrapped tight just to cruise 65 pulling my 5th wheel.I like about 2000-2100 at 65. Plenty-o-power, and you're not spun too high.

[James68352]

Old 6.2, I'm sorry about that. I thought you meant changing out the 1st gear gearing not the OD gearing. Your right your idea is much simpler and cost effective and probably the way I will end up going. The NV4500 is just a niggle I have had in the back of my mind since I saw one in a tonner dually that a contractor had.

Thank you for the information on the tranny.

Jim

[James68352]

David, thank you for the information. That means that I should be good with the 4.10s and my tranny.

Jim

[Old6.2]

James, I checked an old 4x4 magazine over the weekend and the tranny I was thinking of turns out to be the NP-445. I doubt this is the same case as the A-833. The 833 was used in Chrysler hi performance cars in the 60s & 70s and could be found behind the 440s and the Hemi but had ratios too close for your use. Sorry this would not work out for you.

[James68352]

thank you Old6.2, after doing more checking on changing out the diffs and the prices I think I am going to be holding to using this 833 for a while longer. Hopefully it will help when pulling my 5th wheel.

James

[NH2112]

I would consider something inexpensive (relatively) like an SM465 (4-spd manual w/6.5:1 1st and direct 4th), and go with 3.73 gears. Those are low enough that you'll have plenty of power to accelerate in any gear, but won't "quite" be up on the governor at 65mph. High engine RPM while cruising won't hurt anything but can get annoying on the ears. The NVG4500 gives the best of both worlds, but is expensive by itself and I think you'll need an expensive adapter to mount your NP208 transfer case.

[James68352]

Phil, Thanks for the idea. I have read on another post in the towing section discussing a good ring and pinion ratio and they all say 3.73's are the way to go. My only concern is that everyone that says this is running a newer 6.5 with or without turbo.

I'm not overly sure yet just what my budget is going to allow me to do.

Thank you

Jim smile.gif

[James68352]

just an odd question:

what did Chevy list as the horsepower and torque for the 82 6.2L engines? (c code and j code)

Jim C.