Hi folks, The 3.0/1 8" Ford rear in Clarence is needing a new ring/pinion set. It whines on deceleration and while I'm no mechanic my more knowledgeable friends tell me that the ring and pinion gears need to be replaced. Clarence 3,500 pounds (+/-) GM 190 hp crate 350; 4bbl Edelbrock carb; block hugger headers w/ dual exhaust EDIT: trans is T-350 with 1:1 high gear stock torque convertor current gears are 3.0 to 1 rear tires are 28" tall current gas mileage is 15mpg not the most aerodynamic vehicle out there but none of our rods are There are a multitude of gear ratios available. Clarence is a long-distance cruiser. Minimum 10K miles per year. Since the hamb drags no longer exist acceleration isn't really a consideration. If I live long enough to finish it my 400hp, 3,000 pound, 4-sp, '31 Model A will satisfy any need for speed. I want to get the best possible gas mileage after gear replacement as we drive this thing a lot. I can live with replacing the existing gears with more 3.0 to 1 gears and keep on getting 15mpg but better mileage would be a plus. What gear ratio would you recommend for my usage? b-t-w; price fluctuates wildly by brand. Richmond Gear seems to be the most expensive but is about the only brand name that I'm familiar with. They, imo, certainly have the good reputation. Any suggestions regarding brand of gears?
Transmission in your car? As far as gear maker, get US Gear/Strange if you are looking for Made in USA. I have a set of Strange 3.55's for my 8 inch that I'm getting ready to tear in to.
I bet the Edelbrock carb could be leaned down some and maybe a little more ignition advance. Your 3:00 gears have the engine rpm: 60mph 2200 rpm 70mph 2500 rpm. I'd say stick to 3:00 gears with that transmission, or maybe 2:87? Gears are not going to do much for your fuel economy.
Mike, I would pull it apart and see what’s going on. Make sure the ring and pinion look ok and have the correct backlash, etc. Maybe it needs a pinion bearing or something? If you do end up needing new gears, I would likely stick with 3.00 like what you have. Sounds like a pretty good highway cruiser now.
A nice set of 355s would go down smooth, but you would need an overdrive for sure. Not sure how much a Gear Vendors is these days, 2500? Hate to spend that kind of money, but it would be a life changing event for Clarence. -Abone.
Whine in deceleration could just be a pinion bearing but if it has been bad long enough, it could cause R/P damage. There aren't many higher options for a Ford 8". I think 2.79:1 is pretty much your only common option if you want to go higher. It's not really much difference on only 10k miles a year. I once swapped from a 3.70 to a 2.75 in a 9" Ford and the mileage actually got worse.
You're not gonna get better mileage, it's a big vehicle and 15 mpg is pretty good for what it is. I think this is what gimpy is alluding to....keep the ratio you have, since it works. I'd pull it apart and look it over, and see if it does just have worn bearings...but be prepared for changing gears. If you're not doing the work yourself, then you should probably talk to whoever is going to be replacing the gears, and let them get the brand they are most confident in. Since you want them to stand behind their work.
With the multitude of mid sized fords that came with an 8" -3.0 gear , I'd find a good used center section & swap it out ...
Put 2.73's in it if you want better MPG, it's not enough of a ratio change to affect how it drives around town.
I agree that pushing a brick isn't going to win any MPG contests, if you really want to improve, there have been books written, but it boils down to straight tracking low rolling resistance tires and having the engine at the lowest RPM where it develops the most torque and vacuum. As for the rear, they aren't making more, so if you are a junkyard guy, go grab another with the same gears. I don't know all the nuances of interchange, so research that. Once you have that and gaskets and fluid, pop out the current one. Compare on the bench and at that point decide on a swap or repair. You are probably under 200 bucks until you start digging deeper.
Here is some info.......... OK, Thats the tech info, now here is some info on how to build a "Quiet" 9". They are very similar to the 8 inch, so maybe this will help you. OK, thats all I've got but you might want to buy a copy of this book off Amazon.The stuff above is not from this book.
Your 3.00:1 ratio is probably the best for what you want. If the deceleration whine just started, I'd at least pull the pinion to check the bearings and pre-load. If they look good, I'd probably pull the center section and check it over; gear teeth and bearings. If it is all good, you need to decide if you can live with the noise or not. Changing the pinion depth and/or backlash to get the perfect gear tooth pattern probably won't change the noise. That is if all the bearings are in good shape and the pre-load is correct. What it will do is change the speed the noise comes in. The last ring and pinion I did, I purchased from Yukon Gears. It was a nice, quiet gear set. Drove the car for 20 years after the rear end rebuild.
Holy cow!!! That's a lot of reading. I'm not going to attempt that on this phone. Next time I'm sitting at my computer with the larger screen I'll read/study all of that.
Those 8"are well know for noise. I had one in a coupe, 3:55 I think, it had only about 30-40K on it and howled on descent. I figured the gear, got another one and got another noise, even better than the first! Other guys told me they had the same experience with them and to learn to live with it.
When I worked for a heavy truck leasing company, we did a lot to measure and work on fuel economy. The largest single factor to improve fuel economy was the operator. You want better fuel economy, drive a steady speed. Cruise control helps with highway economy. Anticipate stops and back off early. The more you use you brakes, the more you have to use the throttle. Every time you open the throttle, even a little, you give a little squirt from the accelerator pump. Don't idle unecessarly. Run radial tires properly inflated.
You might want to give some thought to an upgrade. The Ford 8" was considered a 'medium duty' rear axle internally at Ford and they limited its use to 302 or smaller motors in the lighter small and intermediate models. If a 351 or 352 was specced, you got a 9". You're running more cubic inches and vehicle weight (particularly if you use it to haul any weight) than it's rated for. Full-size cars (before they 'downsized' them) got the 9" regardless of engine size because of the weight issue. The problem wasn't with horsepower, it was torque rating. The '62-64 axles had issues with premature pinion bearing failures so Ford did do an upgrade starting in '65, with only slightly larger bearings due to design limitations. That mostly eliminated the problem but not completely in non-stock use such as what you're doing. Ford dropped the design in 1980. A 8.8" will be the least expensive choice, with nearly the same strength as a 9". The problem here will be gear ratio as Ford started supplying OD transmissions in many vehicles at the same time it was introduced, so 'tall' non-OD gears can be a bit rare, as well as finding one compatible with drum brakes. You can get whatever you want in a 9", but it probably won't be cheap.... The 8" axles still have value when used right, you may be able to sell it and put a serious dent in the cost of an 8.8 swap. Something to think about...
You need to check out the noise, so drop the 3rd member and check it, or have it checked. But if it needs a new ring and pinion I think the 3.00 to 1 is a great ratio for highway and city. I personally think taller 2.74-2.79 gears will make you unhappy for city driving around town. They will be nicer at freeway speeds, but make it doggy at slower speeds.
Just read the first page and take @2OLD2FAST 's advice and buy a whole drop out head. At 65 mph with a 3.0:1 you should be cruising at 2480 rpm [this is allowing for 6% converter slippage] If you install a 2.78:1 you would cruise a 2306 rpm at 65 mph The 2.78:1 is not a desirable ratio , so you could pick one up dirt cheap to try out. If you're towing keep the 3.0:1 gears. [but run a decent trans cooler]
The difference between the 3.0 and 2.78 in 1st gear up at 1600 rpm is only 1.7 mph [converter stall speed of 1600 rpm] Once the vehicle is rolling the difference is hardly noticeable [over 5mph which is walking pace ] This above should be considered
I agree with above, I'd check pinion bearings first. If they are good then I'd look at gears. I'd just stick with the 3:00 gears, not a big enough jump to really notice a difference and as also stated I'd doubt gas milage would change. My old firebird had a 400, auto and 2:56 rear gears and was a dog, went to 3:23 gears and much funner to drive and I would bet no more than .5 miles per gallon difference. One thing I noticed is the engine revved smoother, ran smoother on the road. I figured it was because the motor didn't have to work as hard to move the weight down the road..... it now how torque multiplication to help it.... .....
Back during the '70's gas crisis/van craze one of the van mags did a spread/test on ways to improve gas mileage. Of all the "improvements"/modifications the only noticeable improvement was removing the side view mirrors. Vans of that era had the same aerodynamics as does Clarence. i.e. brick. Just a thought.
I have 300’s in my 32 sedan but have a T5 . I like the gear, I can motor at 80 all day long but a turbo 350 might be winding it up a bit.
Gear ratios and fuel mileage will depend a lot on how the engine is built and your driving habits. The 3.0 is probably the best one for your truck. As for the strength, I have run e" rears behind some pretty strong 350's without problems but, in light weight cars. The small bearing 9" uses the same axle and axle bearings as the 8" so the weight capacity would be the same. The small pinion bearing can be a problem but, I imagine that Clarance isn't much heavier than my avatar (3500 #), which has a small bearing 9", so the only time that would really come into play is pulling away from a stop or climbing steep/long grades. That being said, there have been some good suggestions here, like sourcing another 3.0 drop out unit, so you could replace the existing one, keeping the vehicle usable, then you can diagnose the problem with the current unit, or just pull it and check it out. The decel whine could be gears, pinion bearings or even a loose nut holding the yoke onto the pinion causing the bearings to be loose (had that happen one time).
Here are some 3.00 ratio Ford 8' ring and pinion options/prices from rockauto.com The Richmond Excel line uses a (partial?) recycled steel content: EXCel gears are made from reclaimed 8620 steel for strength and durability The "regular" Richmond use new steel: Made in Italy, at the highest quality manufacturing facilities Made from Richmond's highest quality steel and cut from first run steel forgings I have used Motive Gear R&P gears in the past, and was happy with them. They are the cheapest, too, in this case: Engineered to Motive Gear's specifications using a proprietary European spec'd alloy
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