Ring & Pinion -Yukon Gear 3.73 Question

[thelawdoc]

Gentlemen, one of the last major items for me to become familiar with on my recently acquired '65-'66 C10 250-Powerglide 2spd is the rear end. I was assuming that I had the base differential, i.e., no positraction or limited slip. But today, in going through a box of stuff that came with the truck, I found some receipts. One receipt, dated about 16 months ago, is an invoice for a differential overhaul. It is itemized. My eye caught the following items:

Ring & Pinion - Yukon Gear 3.73; Bearing - Drive Shaft Center Support; Axle, etc., etc.

My question: Isn't this a 'limited slip' or 'positraction' rear end?

The reason I am so curious is that this truck is slated for daily use in northern winters. Therefore, I had intended on trashing my stock rear end and putting in something more suitable for long winter climates, e.g., limited slip. I figure that with studded rear tires or chains, I would manage ok. And I figured that, if I am trashing my rear end then I will also put in a diff that is more suitable for better mpg & low rpm's on the interstate. But if I already have l.s., and the diff has just been overhauled, I will sit with what I have and be a sport for the money spent on gas using the 3.73 on the freeway.

I am attaching a copy of the invoice so that you can see what I am seeing.
Thank you for the help. -Alden

[66Submarine]

It doesn't mention limited-slip anywhere; the Yukon ring and pinion is just a replacement gear set.

[thelawdoc]

Thanks, 66. I was hoping that if a guy is doing a diff overhaul of a 50 year old truck that he would think about limited slip. Well, I am not crazy about the 3.73 anyway, so I might as well trash it for something a little better on the highway and in snow. Seems like a shame to let such recent work and money go to waste. But without l.s. for winter, I am not sure that studded tires will be of much use. Alden

[jtrichard]

so put a limited slip diff in it its not that hard

[thelawdoc]

Jtrichard, Yes, the plan will be to swap the pinion and ring gears for highway gears and to add on some style of l.s. This is a job for a shop. It is waaay out of my league. But I think it will be money well spent. It is just a little disappointment for me, since I had, albeit naively, assumed that all trucks would have l.s. and highway gearing when I decided to take this, my first, truck. Ok, time to rearrange the budget...again.

[PGSigns]

Well most were open carriers and they had gearing for there intended use, a truck. And they were not bad on the highways of there day. With the 1.82 first gear in the 6 cylinder power glides 3.73 was needed to get them going. If you go to a 3.08 you may find it a little lacking on low end power.
Jimmy

[thelawdoc]

PG, Yes. I suppose what you say means that it would be better for me to keep the glide's gearing, just add in l.s., and then bolt on an overdrive. The bolt-on o.d. will run about $3k. Do you have any guess as to the cost of adding in LS?

[LT1 Burb]

Doesn't say but holy crap previous owner got taken to the cleaners on that repair.

[thelawdoc]

LT1, the invoice is out of Decatur, Il. May 2013. A tranny shop.

[LT1 Burb]

Its a little pricey,I got my posi one with 3:73 done for under 800. Easiest way to tell if you don't want to drop the pan and look ,is to jack it up and turn a wheel, see if both roll. Posi carriers aren't that expensive, 100-150 used and you can use the same gear set if you get the right size.

[thelawdoc]

LT1, well the invoice includes other parts and work, so maybe the shop is not so pricey. The invoice does not seem to indicate any work on ls parts, e.g., clutch plates. But I know so little about differentials, I don't trust myself to look at the invoice and reckon exactly what I have. So I guess jacking up the truck is the best idea. {Edit: Ah, if just a few hundred for ls, then I am good to go for that.}

[65Gregg]

I would keep what you have. I'm running the same rear set up except I have a 700R trans, it has great highway manners and with the low 1st gear it pulls real strong. To convert to LS power your cost will vary depending on what you have to spend for the engine/trans etc. Don't be afraid to tackle the install yourself, there is enough info and knowledge here to guide you along the way.

[thelawdoc]

65Gregg, well I was hoping not to have to spend anymore money on the engine or transmission. I recently had the unexpected expense of a tranny rebuild. The reason I am dwelling on the rear end right now is primarily out of concern for the northern winters that await the truck, and secondarily for highway mpg. I can chill out about highway mpg -I won't be doing more than 4k miles a year on the interstate. But I wonder about being on icy or snowy roads with an open diff. Locals seem to frown on rear ends that lack positraction, whether you have snow tires or not. I would not be doing a lot of snowy weather driving (I am retired), but I am sure that I will find myself out sometimes with some snow or ice on the road. What is your opinion? If it be only a few hundred bucks, I would think I would be foolish to go without it in the northern climes. I am trying to be wise. I can't do the add-on myself of l.s. because I have no shop space or the tools for axle work and I lack the experience to get the job done quickly in the driveway. Being a novice, I perform tasks with books open, step by step by the numbers. (A guy like me is allowed to have one of these trucks not as of right, but by the grace of guys like you on these forums.)

[padresag]

I would be more concerned about the salt damage that you will be introducing it to. it won't take that long that you would have to worry about axle ratio.
it has already survived 50 years without a posi
ron

[thelawdoc]

Padresag, Yep, the salt is a migraine. But there is not much that one can do. I have to use the truck. It is not in show condition. It is a sole vehicle, daily driven. At some point -and I suppose sooner rather than later, I will have to see about treatments for the underside to resist road salting. But in general, I will just have to find opportunity to slide under her and have a look to see what, if anything, is going on. One can only do what one can only do.

[Clyde65]

lawdoc, I am a computer guy and I jumped on the LSx bandwagon. It was not that hard and with the assistance and some key guidance from many members here, I got it running and on the road. That was 4 years ago! I get ~20MPG hwy and it starts every time without fail! drives well and I have AC!

[thelawdoc]

Clyde65, Hmmmm. You computer guys... Well, if I had a 3D printer I too could just print out a new differential for myself. And 20 mpg? What are you feeding that girl? I get maybe 12-13 mpg and I am not sure if that is reality or in my dreams at night! But I am on it. Right now I have a carb kit on its way to me. My carb is laid out on the dining room table, like a 500 piece puzzle. I sure hope the mailman who brings me the kit knows how to put this carb back together again...

[66Submarine]

Originally Posted by thelawdoc

Clyde65, Hmmmm. You computer guys... Well, if I had a 3D printer I too could just print out a new differential for myself. And 20 mpg? What are you feeding that girl? I get maybe 12-13 mpg and I am not sure if that is reality or in my dreams at night! But I am on it. Right now I have a carb kit on its way to me. My carb is laid out on the dining room table, like a 500 piece puzzle. I sure hope the mailman who brings me the kit knows how to put this carb back together again...

My big and heavy '65 one ton got 14MPG last check; upper teens is easily achievable with the old stuff in a half ton IME. 12-13MPG is just abysmal IMO.

I'm a fan of the LSx series myself, but IME/IMO the old stuff still works much better than most give it credit for these days.

[WhippinSaw]

Originally Posted by thelawdoc

Padresag, Yep, the salt is a migraine. But there is not much that one can do. I have to use the truck. It is not in show condition. It is a sole vehicle, daily driven. At some point -and I suppose sooner rather than later, I will have to see about treatments for the underside to resist road salting. But in general, I will just have to find opportunity to slide under her and have a look to see what, if anything, is going on. One can only do what one can only do.

Took mine to Ziebart, still rusted out. You have a beautiful truck, hate to see it get rusty.

[Snailed]

Hey guys - The original poster isn't talking about 3rd and 4th gen Chevy smallblocks, he is using LS to abbreviate Limited Slip.

As for driving without one in the snow, it's totally fine and millions of people do it every day. I bet 90% of cars and trucks on the road have open differentials. My daily driver is a '66 and I drove it every day last winter with an open diff. I put some 29" narrow snow tires on it and about 400lbs of stuff in the bed and it did great. Didn't get stuck or slide around (by accident) even once. The C10 was far easier to drive than my last car which had the same model snow tires, rwd, limited slip and electronic traction control. When you are in the car enthusiast bubble you forget that it's a bubble. Pretty much no one wants or needs (except whoever is reading this haha) limited slip diffs so only a select few vehicles come with it.

Just noticed you're in Brooklyn! You Really don't need it. I go there in the winter all the time and it's much more mild than where I live.

[66Submarine]

Originally Posted by Snailed

Hey guys - The original poster isn't talking about 3rd and 4th gen Chevy smallblocks, he is using LS to abbreviate Limited Slip.

As for driving without one in the snow, it's totally fine and millions of people do it every day. I bet 90% of cars and trucks on the road have open differentials. My daily driver is a '66 and I drove it every day last winter with an open diff. I put some 29" narrow snow tires on it and about 400lbs of stuff in the bed and it did great. Didn't get stuck or slide around (by accident) even once. The C10 was far easier to drive than my last car which had the same model snow tires, rwd, limited slip and electronic traction control. When you are in the car enthusiast bubble you forget that it's a bubble. Pretty much no one wants or needs (except whoever is reading this haha) limited slip diffs so only a select few vehicles come with it.

Just noticed you're in Brooklyn! You Really don't need it. I go there in the winter all the time and it's much more mild than where I live.

Yeah. I watched an impromptu hill climb when it snowed a bunch here this last winter, and it was funny seeing what made it up and what didn't. A flat black SWB '67-'70 with an open differential and no weight (I could see) in the back motored up the hill about as good as anything, actually passing a late model car that spun out and got stuck halfway up.

[thelawdoc]

Well guys. You took some weight off of my shoulders with your comments. Sometimes I feel truly humbled when I read responses to my queries. God bless you all.

66, I will get her mpg up. I am sure of it. I am going to sit with the relevant parts and data sheets and get them up to spot-on spec. Each and every one. Starting with the sock in the gas tank and finishing at the tire treads. The day is not long off when I will come back to this thread and report my mpg. It is pure joy for me to sit for hours with a carburetor puzzle, checking each and every piece of it before putting it back. What, sitting for hours in front of the idiot tube is better? And the same goes for any other part that I can learn about and handle. If you guys can give of your time when I need it, I will at least do my part. Some of it is tedious. But all of it is doable. Regarding winter conditions driving, a tow truck operator friend of mine told me recently that he has to go help as many 4WD vehicles as he does any other kind of vehicle. He says they end up in the ditches because their drivers think that 4WD makes a vehicle a HumVee. He says the only vehicle perfect for snow is a snowmobile. That is why I did not go for 4WD. I also couldn't afford it and its maintenance. Better I should put my limited funds into good snow tires. Then, if there be conditions that my truck cannot handle, I will use an ATV.

WhippinSaw, I cannot say that rust will never trespass my truck. I can say that I will find it and be rid of it. I have jack stands, good work lights, and restored vision. Rust is not going to nibble at my truck.

Snailed, thanks. Brooklyn roads are plowed reasonably quickly after snowfall. But I am moving very soon to northeastern Maine. I see you are in Portland. I will be in Linneus, just south of Houlton. I have a dirt road of about 3 miles to cover between the paved/plowed town road to my property. It is a pretty good dirt road based on my experience, and there are other people living not far from me who do plow it as best as a dirt road might be plowed. I just want to do whatever I can, within a tight budget, to have my truck at her best. For the time being, it will be some good snow tires.

Thanks, guys.
Alden

[Clyde65]

Originally Posted by thelawdoc

Clyde65, Hmmmm. You computer guys... Well, if I had a 3D printer I too could just print out a new differential for myself. And 20 mpg? What are you feeding that girl? I get maybe 12-13 mpg and I am not sure if that is reality or in my dreams at night! But I am on it. Right now I have a carb kit on its way to me. My carb is laid out on the dining room table, like a 500 piece puzzle. I sure hope the mailman who brings me the kit knows how to put this carb back together again...

Lawdoc, I have an LS with an OD trans.