steering box ratio?

[v30crewcab]

so how many different steering box ratios are there, and how do you go about telling them apart? I have two different boxes, not sure how to tell them apart. one is my 88 crewcab box, and the other is a 84 3/4 ton single cab box. would they be the same ratio? I know the 88 has a stiffer torsion bar in it. it was harder to steer than the 84 box. it felt like a 88up bodystyle truck.

[Axle]

Still have the spids for the trucks it came out of? My '83 is a variable ratio box, spid code N41.

[v30crewcab]

no my glovebox was missing out of my v30, and I don't have the 84 anymore either. don't guess you could get a list from a vin # somewhere can you?

[Keith Seymore]

Originally Posted by v30crewcab

no my glovebox was missing out of my v30, and I don't have the 84 anymore either. don't guess you could get a list from a vin # somewhere can you?

Yes, but it will cost you $50 for each VIN. And it won't tell you the steering ratio.

http://www.gmmediaarchive.com/?page=3

K

[Keith Seymore]

Originally Posted by Axle

Still have the spids for the trucks it came out of? My '83 is a variable ratio box, spid code N41.

N41 is the RPO for Power Steering (doesn't affect the ratio).

I think the ratios are the same between an '88 crew and a '84 3/4 ton but I can't confirm that. None of the documentation I looked at specified the ratio.

K

[v30crewcab]

so I guess the only way to know is to take them apart.

[Keith Seymore]

Originally Posted by v30crewcab

so I guess the only way to know is to take them apart.

I wouldn't recommend that.

I'd be afraid there's a bunch of springs and balls and stuff that would come flying out in all directions Additionally, the preload and overcenter torques are "set" so you would lose that adjustment. Plus - there's not "gears" in there that you can count teeth, like a ring and pinion. It's a shaft with a spiral on it so I don't think it would tell you anything conclusive.

You can't clamp them in a vise and spin the input, noting how many turns lock to lock for each? Seems like that would tell you what you want to know.

K

[v30crewcab]

I wouldn't recommend the average person take one apart either, but I'm a mechanic, and I've rebuilt several of these before, so Its not too big of a deal for me! not sure how you'd know it was variable or not though.

[Axle]

Keith, I have this jotted down, pulled from an old GM rpo reference booklet;
N40 = power steering, non-variable.
N41 = power steering, variable ratio.
N51 = manual steering.

comparing my 83, to the 81, the 83 definately has the more responsive steering in it. But I have no codes for the '81 so no way to confirm what its code is. But there is a distinct difference in steering input required pointing to a variable ratio box in the '83.

Alex.

[INSIDIOUS '86]

What were the ratios available for these trucks 73-87(91)?

[Keith Seymore]

Originally Posted by Axle

Keith, I have this jotted down, pulled from an old GM rpo reference booklet;
N40 = power steering, non-variable.
N41 = power steering, variable ratio.
N51 = manual steering.

comparing my 83, to the 81, the 83 definately has the more responsive steering in it. But I have no codes for the '81 so no way to confirm what its code is. But there is a distinct difference in steering input required pointing to a variable ratio box in the '83.

Alex.

Thank you, Alex. It was interesting (to me) to note the generic info packet didn't say anything about variable vs non-variable. That might indicate they were all the same.

Originally Posted by INSIDIOUS '86

What were the ratios available for these trucks 73-87(91)?

I don't know or don't recall.

I know the engineer who designed the system but he retired many years ago and our paths have not crossed since. He was the suspension engineer in addition to steering.

K

[Axle]

Thats a minor quibble I have with the generic info packet, its very generic. And if memory serves, its the same general information found in other GM service publications. Better than nothing however.

Alex.

[Axle]

Found the other location I had seen them, download the parts book from Hatzies PDF manual thread;
http://67-72chevytrucks.com/vboard/s...d.php?t=545416
In the 78-84 parts book, page 120 of the pdf.

[y5mgisi]

Subscribed.

[K20chevy]

Can you tell the steering boxes appart if the RPO lable is gone?

And does anyone know if PSC or Howe use the variable boxes or the non-variable ones?

Thanks!

[wraprail]

Did anyone notice NY2, NY6 and NY8 on the list above? Maybe the 605 and 800 are two wheel drive and four wheel? NY2 though......steering
slow ratio?

[Axle]

Have you ever seen the square body airplane tug? Max speed maybe 15mph(?) Potentially slow ratio. Street sweepers, and other slow moving special purpose chassis only vehicles may have been recipients of a slow ratio box.

[v30crewcab]

never seen one with a 605 box.

[Axle]

Those RPOs don't apply exclusively to squares.

[v30crewcab]

well I have several boxes, all of them are 3 turns, except one which is a 4 turn, and I think its off a stepvan. guess I will use the cleanest of the 3 turns as thats the same as whats in the truck now. no idea how to figure out if its variable or not without a teardown.
kind of important to just get one on it now as it got wrecked thurs night and killed the box on it. not exciting.

[Axle]

Put an indicator on the output shaft, set the box "straight ahead" and turn the input shaft a half turn/full turn. The one that moves the output shaft more degrees than the others would be quicker ratio. If they all move the same, then use the whatever you prefer.

Alex.