77 GMC Steering Gear Box and Suspension

[Rnd]

I have a '77 GMC 3+3 two wheel drive 3/4 ton.

It drives really loose on the highway. All the bushings and steering linkage are in good shape, it's just the way they built them in the 70's.

I was wondering if anybody has tried to change the steering gear box out for a closer ratio box?? ie. this box is 3 & 3/4 turns from lock to lock. In the eighties they had some that were 2 & 1/2 lock to lock.

Also this truck didn't come with a front sway bar. Has anybody added one? Did it help with the body roll?

I guess I'm trying to get a firmer/tighter feel when on the highway.

Any suggestions??

Thank you,

[frog210]

My 74 c10 is 2 1/2 turns lock to lock
i drove my truck without the factory sway bar on, and didnt like it
I have a factory sway bar if interested let me know..

[Loose Cannon]

I've got a '77 C10 running 32" tires and it's as tight as any new truck I've driven (of that size). It's not going to beat a Corvette in the slalom, but it's feels pretty good to me.

It could be a worn out steering box, could be many parts working against you.

With your truck parked, have someone turn the wheel a few degrees left and right over and over while you watch the linkage work. You'll probably spot the issues then.

[frog210]

^^^ that or lift the front up maybe like 4-6 inches of the ground and move side to side or up and down and put a pipe under the tire and try to pick it up you can find out what needs to be repaired
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[Loose Cannon]

Here's a video to demo the idea:

http://www.youtube.com/watch?v=HKk33w86OSI

[Rnd]

Thanks for the ideas guys but, as I mentioned in my OP components are not worn out or, out of adjustment.

Gear box has appx. 4 turns lock to lock = big movements in steering wheel to correct. Frogs '72 has 2 1/2 turns lock to lock...Will that bolt onto a '77 ?

Truck came from the factory without front sway bar...C-10, G-10 and G-20 had sway bars....C-20, C-30, G-30 ,P-10,and P-30 did not come with sway bars....(in the 2 wheel drive models)

Has anybody added a sway bar?? what was involved?? ie are the holes drilled in the frame and control arms? Or would it be a total custom install?? Did it help?

[frog210]

It should have maybe the holes or the rivets, maybe it has the sway bar bracket if not let me know, I have the bracket off and can send you a pic if needed
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[Tx Firefighter]

Originally Posted by Rnd

Thanks for the ideas guys but, as I mentioned in my OP components are not worn out or, out of adjustment.

Gear box has appx. 4 turns lock to lock = big movements in steering wheel to correct. Frogs '72 has 2 1/2 turns lock to lock...Will that bolt onto a '77 ?

Truck came from the factory without front sway bar...C-10, G-10 and G-20 had sway bars....C-20, C-30, G-30 ,P-10,and P-30 did not come with sway bars....(in the 2 wheel drive models)

Has anybody added a sway bar?? what was involved?? ie are the holes drilled in the frame and control arms? Or would it be a total custom install?? Did it help?

That's not quite correct. It was an option on all of them. Yours just didn't get ordered with one apparently. They are easy to add, and all trucks are set up for them from the factory. I wrote an FAQ article about adding one to trucks not so equipped. Find it in the FAQ section.
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[Loose Cannon]

In regards to the steering box part of the question:
O'reilly recommends the same steering gear box in all '77 C10, C20, C30, C15, C25, and C35 trucks so the bolt pattern is the same for all. So go ahead and swap it out with a 2-1/2 turn box.

Be sure to note how your turning radius is now beacuse when I bought a "quick ratio" box for my El Camino I lost quite a bit of angle, now I cant turn around on a normal street without backing up.

(avoid the 4wd gear box because the output shaft will have different splines)

[Rnd]

Thanks Tx Fire,

Thats the kind of info I was looking for....Great write up.

It took me awhile to find it so if anybody else is looking here it is.
http://67-72chevytrucks.com/vboard/s...ad.php?t=72338

And one other I found while looking

http://67-72chevytrucks.com/vboard/s...d.php?t=351586

Loose Cannon, Thanks for the steering gear info. Now that I solved the sway bar install I'll look a little deeper into the gear box and see if that is a feasible swab.

[mrolds88]

My 77 GMC CC dually has a front sway bar. I owned an S10 once that ddnt have one. It handled like a beer can.

[Rnd]

http://bangshift.com/blog/driveway-t...two-tools.html

Does anybody know if the close ratio gear box in the above link will work (bolt on)

They were used in about the same time period...Just a thought

[Rnd]

Originally Posted by Rnd

http://bangshift.com/blog/driveway-t...two-tools.html

Does anybody know if the close ratio gear box in the above link will work (bolt on)

They were used in about the same time period...Just a thought

Never mind.....It won't work

[Keith Seymore]

The other thing you can try easily is cranking the caster up to 10 or 12 degrees positive, by adding a tapered shim between the spring and axle pad.

This will help with "on center" feel and straight line stability.

K