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Mark Wilson

New member
Jun 13, 2024
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My wife and I are avid campers, we have morphed through tents, class “C’s”, class “A’s, and currently have a 36’ fifth wheel that is aging out. Our children are grown and we are nearing retirement and we’re looking for our retirement RV. My father owned an automotive repair shop in the 70s and 80s. As a child I remember these GMCs coming through on occasion for repairs. In my child’s mind they seemed magical and futuristic, it stuck with me, every time I would see one on the road, it caught my eye.
So, we had decided on locating a low mileage class C to purchase, as we looked through the marketplace my wife spotted a GMC and said, “I wish we could find one of these, they look cool.” I never told her how much I admired them. With that bit of encouragement I said, “say no more”. The main problem with our search was every time we found one we liked it was always 1000 + miles away. I don’t know if it was God’s good graces or dumb luck, but a 77 Eleganza popped up on marketplace 80 miles away. It was like a time capsule, the owner’s son said his father purchased it in the 80s from the original owner and babied it. The owner sent it through Golby’s in the late 90s and had extensive overhaul and service performed at 68,000 miles and had the receipt's. He unfortunately passed a year later. His son kept it in storage for 24 years only driving rarely. I couldn’t pay this man fast enough! 73000 miles on the clock, I put a new battery in it, rigged a 12 gallon boat fuel tank to the pump and drove it home.
The past 8 months I have been following Jim Bounds advice step by step and trying to keep it as close to original look as I can. My next project is to change the final drive ratio from 3.07 to 3.70 as I want to tow an older Wrangler. I was a master automotive technician for most of my life and was looking for a supplier for the 3.70 ring and pinion, not only because I’m borderline DIY crazy, but the cost of a new unit and shipping.
Hurricane Helene severely damaged our home and we used the GMC as a lifeboat for two months, my wife has named it “Wanda”.

Mark and Angie Wilson
Ambrose Georgia
 
My wife and I are avid campers, we have morphed through tents, class “C’s”, class “A’s, and currently have a 36’ fifth wheel that is aging out. Our children are grown and we are nearing retirement and we’re looking for our retirement RV. My father owned an automotive repair shop in the 70s and 80s. As a child I remember these GMCs coming through on occasion for repairs. In my child’s mind they seemed magical and futuristic, it stuck with me, every time I would see one on the road, it caught my eye.
So, we had decided on locating a low mileage class C to purchase, as we looked through the marketplace my wife spotted a GMC and said, “I wish we could find one of these, they look cool.” I never told her how much I admired them. With that bit of encouragement I said, “say no more”. The main problem with our search was every time we found one we liked it was always 1000 + miles away. I don’t know if it was God’s good graces or dumb luck, but a 77 Eleganza popped up on marketplace 80 miles away. It was like a time capsule, the owner’s son said his father purchased it in the 80s from the original owner and babied it. The owner sent it through Golby’s in the late 90s and had extensive overhaul and service performed at 68,000 miles and had the receipt's. He unfortunately passed a year later. His son kept it in storage for 24 years only driving rarely. I couldn’t pay this man fast enough! 73000 miles on the clock, I put a new battery in it, rigged a 12 gallon boat fuel tank to the pump and drove it home.
The past 8 months I have been following Jim Bounds advice step by step and trying to keep it as close to original look as I can. My next project is to change the final drive ratio from 3.07 to 3.70 as I want to tow an older Wrangler. I was a master automotive technician for most of my life and was looking for a supplier for the 3.70 ring and pinion, not only because I’m borderline DIY crazy, but the cost of a new unit and shipping.
Hurricane Helene severely damaged our home and we used the GMC as a lifeboat for two months, my wife has named it “Wanda”.

Mark and Angie Wilson
Ambrose Georgia
Applied gmc has always kept a tight grip
On their ring and pinion. From what I know is that the only way you get one is buying the entire final drive from/through them.

Talk to Jeff Iantello about final drives since your in georgia.

Also if your not stuck on the 3.7. The 3.42 from Cinnebar I understand is a little less money.
 
My next project is to change the final drive ratio from 3.07 to 3.70 as I want to tow an older Wrangler.
I believe this fellow changed the gears in his GMC to a different ratio. His name is Mike on YouTube and has over 200 videos of his motorhome rebuild. I don't know how to contact him other than leaving him a message on one of his videos.
He pulled the transmission and FD way back on his #23 and #47 video, But I think there was one on his changing of the gears.
But I may have the wrong guy...

In any case, his videos are pretty good.
 
Welcome, Mark! I'm glad you two found a coach to enjoy.

It's so funny you mention regearing final drives. I just pulled the trans and final drive out of my Palm Beach after a direct clutch failure, and found flakes coming out of the final drive. Since I tow a 4,000 lb boat on occasion and live in the foothills of the Cascades, it seemed like a good time for a regear. I've been talking to Jeff, Applied GMC, Manny, and trying to get a hold of Cinnabar too. Cinnabar may sell 3.42s if a guy can get a hold of them.

Applied's differentials with limited slips do add up fast. Even the rebuild kit with bearings and seals is high--but it might not actually be unreasonable. Just last night I started trying to source some of the diff bearings independently, and wow they're expensive! They're even worse than the front wheel bearings.

Jeff Ianitello is purportedly the designer of the original limited slip differential. He's designed them for quite a few obscure GM applications. You'll see talk of his projects and his defunct website, Engineered Performance (maybe he has a new one I haven't found?), going back 15-20 years on various forums. I'm about to buy one of his limited slips, and he's been very helpful. He supposedly sold his design through Applied GMC for about 10 years, when at some point that relationship dissolved and Applied "found a new supplier" of sorts, but the design seems to be the same. Applied does carry a warranty, but who is actually making Jeff's old design? That kinda rubs me the wrong way, so I'm trying to source things through Jeff if I can.

So right now I'm trying to see if I can put something together without spending a small fortune shipping housings across the country, paying core charges, paying $700 for bearings and seals, etc. I may source the gears independently and source the LSD carrier from Jeff and try to assemble it myself with good used bearings. As far as I know, no one sells an install kit with a shim assortment for this diff, so there's an added complication.
 
Pennywise and pound foolish has always made sense to me. Around 2016 when I decided to regear, JimK talked me into a 3:70. His arguments made sense and I never thought twice about whether it would fit, the correct gasket, or any other fitment issues. I was impressed with the performance which validated his suggestions. I know my 455 is really spinning when I pass someone at 75mph, but it's never seemed a problem. I normally drive around 65 which puts the engine in its happy place. When a failed transmission was traced to a seal issue in the final drive, Jim second-day shipped a brand new one at no charge. In hindsight, that kind of surety that everything will work, plus that kind of ongoing support, justifies the premium price to me. I do not have Paul's intelligence, patience, experience or shop resources to DIY. My experience let me install the final drive in my driveway with no issues beyond some colorful language. YMMV, but I feel some defense of Applied's pricing might be in order.
 
YMMV, but I feel some defense of Applied's pricing might be in order.

Ask and you shall receive! Here's some defense of Applied's pricing. Note: this is for ONE pinion bearing and ONE race. There are two. There are also the side bearings for the carrier. None of them are cheap/plentiful, and this was a cursory search, but good grief! I know the seals are about $50 a pop from Applied, but the truly correct ones are unobtanium elsewhere. I have alternates currently and they're OK, but correct is better.
So their $700 bearing and seal kit starts to seem pretty reasonable when you add things up. Most importantly, they have it!

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Some of us have gone out and found a 66-67 Olds Toro switch pitch trans. The FD attached to those transmissions is a 3.21. Between the 3.21 and the SP capabilities, we end up with the best of both. Lower gear, but not to low and the SP for that little extra needed when gliding up a 6 or 7% grade mountain pass. Most 3.21's right out of the junk yard can be just bolted up with a change of seals and oil. Just something to think about.
 
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Pennywise and pound foolish has always made sense to me. Around 2016 when I decided to regear, JimK talked me into a 3:70. His arguments made sense and I never thought twice about whether it would fit, the correct gasket, or any other fitment issues. I was impressed with the performance which validated his suggestions. I know my 455 is really spinning when I pass someone at 75mph, but it's never seemed a problem. I normally drive around 65 which puts the engine in its happy place. When a failed transmission was traced to a seal issue in the final drive, Jim second-day shipped a brand new one at no charge. In hindsight, that kind of surety that everything will work, plus that kind of ongoing support, justifies the premium price to me. I do not have Paul's intelligence, patience, experience or shop resources to DIY. My experience let me install the final drive in my driveway with no issues beyond some colorful language. YMMV, but I feel some defense of Applied's pricing might be in order.
I want to set up my GMC to flat tow a 3200 pound Wrangler. From what I have researched the 3:70 would be good for me. We like to road trip, pick a direction and go, staying off the interstate and pull 55-60. I have set up dozens of differentials, I have the tools, experience and time. And I enjoy doing it, it’s one of the reasons we purchased what we did… it’s going to need a lot of restoration. From my point of view it would be foolish not to pursue acquiring a master ring and pinion set that includes all the bearings and shims, usually between 300 to 500 dollars. But, so far that doesn’t seem to be an option. I’m positive Applied’s final drives are worth every penny, they certainly warranty them well. I will probably buy one soon, after I give due regard to all options.
 
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I want to set up my GMC to flat tow a 3200 pound Wrangler. From what I have researched the 3:70 would be good for me. We like to road trip, pick a direction and go, staying off the interstate and pull 55-60. I have set up dozens of differentials, I have the tools, experience and time. And I enjoy doing it, it’s one of the reasons we purchased what we did… it’s going to need a lot of restoration. From my point of view it would be foolish not to pursue acquiring a master ring and pinion set that includes all the bearings and shims, usually between 300 to 500 dollars. But, so far that doesn’t seem to be an option. I’m positive Applied’s final drives are worth every penny, they certainly warranty them well. I will probably buy one soon, after I give due regard to all options.
Very often a new owner starts working on their coach and hitting the internet for less expensive parts. After much time spent on a exhaustive internet search they learn that the parts are no longer available. It is often by the numbers that our few suppliers can gather that they are able to convience someone to produce a part. And nobody is getting rich doing it, for sure. It is mostly out of love for the community and the coach that they continue. If they were to stop or not hand over the tourch when they retire the coaches will become worthless over night, (and really almost over night). I will always support and thank Jim K., Dave L., Jeff S. Keith V. and Steve and all the others who invest their time and energy. Please support them. No matter what one thinks or does, you will eventually find your way back to our vendors.
 
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I want to set up my GMC to flat tow a 3200 pound Wrangler. From what I have researched the 3:70 would be good for me. We like to road trip, pick a direction and go, staying off the interstate and pull 55-60. I have set up dozens of differentials, I have the tools, experience and time. And I enjoy doing it, it’s one of the reasons we purchased what we did… it’s going to need a lot of restoration. From my point of view it would be foolish not to pursue acquiring a master ring and pinion set that includes all the bearings and shims, usually between 300 to 500 dollars. But, so far that doesn’t seem to be an option. I’m positive Applied’s final drives are worth every penny, they certainly warranty them well. I will probably buy one soon, after I give due regard to all options.
3.7 will be best for towing.

When people discuss final drives as it relates to a 455. There is varied opinions. Those that like to drive faster sometimes complain of the higher rpms and associated noise levels. But the 3.7 will always handle a drag and hill better.

I am running 3.21 gears and have hauled a jeep. And currently drag a similar weighted honda crv. I would like lower gears for that, but when not towing…. My 3.21 is just right.

Good to have more diy. Not many like to dive deep into setting up a differential. I had the opportunity to tear my 3.21 all apart, check all bearings and re-seal it alongside a guru. I will not do one by myself, as it seemed there are things to watch out for that experience can only help.

My experience with towing all sorts of things with my gmc and my friends. is if you can stay 3000 pounds hauling or less you are better off. Creeping up towards 4000 pounds it is really a tougher drive. Towing a 2000 trailer is really easy.