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He everyone. I have a 1985 Camaro with the LG4 (305 carb) paired up with a T5 transmission with a current 3.73 rear axle ratio. I don't know if it came with this gearing from the factory but that is what is in it currently. I am going to rebuild the rear end and replace the ring and pinion. Is a 3.73 the best ratio for the 305 with a manual? or would a slightly lower gearing work better? Would there be much of a difference? This car is more of a daily driver and meant to be fun to drive around.
Some background information... The car has been making a loud high pitch whine ever since I got the car. The sound is non-existent while accelerating, but is very loud at a constant speed. When coasting in gear, it is quiet, although it is still there subtly when coasting in neutral. I thought it was the transmission at first, so I rebuilt it, replacing all of the bearings and syncros. The only parts that weren't replaced were the gears. After finishing the rebuild and putting the tranny back in the car, it still did the same sound. So now I am looking at the rear end. The axle ratio that is in there is 3.73 and I counted the teeth. I dont know if it came with that ratio, and it is obvious somebdy else was in there before me since the cover was sealed by rtv, not a gasket. i checked backlash of the ring & pinion, and came up with 0.017 to 0.020, which is too much play. I also checked the wear between the teeth, and it seems to be closer to the outer edge on both sides. So I plan on rebuilding the rear end.
I don't know if it came with this gearing from the factory
In fact, it did not. It was probably 3.23 originally.
3.73 is generally preferred to 3.23. If you swapped to 3.23 it would feel like you were taking off in 2nd all the time, and had a 6th gear.
The noise is probably the pinion bearing worn out. The excess backlash is probably the carrier bearings, or more accurately, the shims that are supposed to provide preload for them. The gears are probably OK and don't "have to" be replaced. But, as cheeeeeep as they are, doesn't make much sense to replace all the rest of that, and leave the old ones in there.
I think only the HOs came w 3.73s. I've driven LG4/t5 w 3.23/3.55(?)s 3.73 and 4.10s. The t5 has a pretty low 1st, 4.10s were terrible. The 3.73 was the most fun but 1st was almost too short and the 3.55(or what ever it was like that) was almost cool in first but lacked in the upper gears. I feel like 3.73 is the best w a t5.
There's no replacement for displacement. But mechanical leverage sure helps.
I agree, the T-5 / 3.73 is a very good combo. Especially when the engine can rev better than a stock LG4, which is severely restricted by its exhaust and its pitiful cam, which, if it was looking for a bra to cover its bumps, it would be told to use Clearasil.
Agree with what was stated already. The original rear gear would have been 3.23. Someone replaced the gear set with 3.73's and sounds like they didn't set it up correctly. 3.73's are a good choice for an LG4/T5. I would also agree with replacing the gear set along with the bearings and setting it up correctly with proper bearing preload and gear backlash. The gearset isn't very expensive and while you could reuse the old one, it has been worn in with an incorrect setup. When you set it up correctly, it may very well continue to make noise because of the previous wear. New gears set up correctly have the best shot of being quiet.
Upon further inspection, I realized I cannot count. It does have the 3.23 gear ratio (42:13), but it is a G80. I know because I can see the gov-lock parts. Maybe someone replaced just the carrier? When I took the cover off of the diff, there was a considerable amount of metal, and one piece is pretty significant. I will link a picture. I am debating if I should replace the whole carrier as well, or just replace all of the bearings, shims, and ring & pinion as mentioned before. I do not know anything about the history of what was done or for the whole vehicle for that matter.
If I was going into that rear, I'd start w all new parts, diff/gears/all bearings and seals. There's a variety of different ratios you can change to but keep in mind, you'll need to deal w your speedo if you change ratios. It's not a big deal, just something to know.
At the point of buying a carrier, gear, & all bearings, consider REAL CAREFULLY what rear you ACTUALLY have.
In addition to the parts that 82 listed, you'll also want axles, since yours are almost certainly DESTROYED, like everybody else's. Specifically, the axle itself IS the inner axle bearing race; and since stock axles are roughly the consistency of warm butter, they erode severely at that spot, ALWAYS. You can change the bearing itself every single day, and twice on Sundays just for good measure, and the WHOLE SYSTEM will STILL act like worn-out bearings, because THEY ARE. The inner race is still garbage. So you NEED axles, whether you've noticed it yet or not.
The axle tubes are almost certainly loose in the pumpkin. They always are. Each side of the pumpkin (cast iron) has 2 holes about the size of a dime in the holes that the axle tubes (steel) jam into. They then use "plug welds" to retain the tubes. You can imagine how well that works; or maybe, you can just go out and look. If your rear leeeeeks from any of those, then that tube, at least, is GUARANTEED to be loose. I had one car once that made this strange "pop" noise coming to a stop sometimes, especially after a hard acceleration; I looked for the source of it for YEARS; finally one day, after a trip to the car wash to clean up all the axle grease that kept leeeeeking out but I couldn't find where it was coming from, I noticed a witness mark around the plug welds. Turns out the "pop" was the tube rotating in the pumpkin. When I took it out, I could literally turn and wobble the axle tube around BY HAND. The point being, you will almost certainly need to have somebody straighten and align the rear with some sort of fixture, and weld the tubes in with some more permanent technique, including filling in the leeeeeky plug welds. Since it involves welding cast iron it'll have to be heated up pretty hot in an oven. Not cheeeeeeeep.
Depending on how much of the labor you can do vs having to pay somebody else to do it, you're talking about dumping anywhere from $1200 to $1800 into this thing, if you want it REALLY right. It makes no sense to spend THAT MUCH "rebuilding" a core that isn't EXACTLY what you want. Meaning, if it has drum brakes, as nearly all LG4 cars would have, [insert obnoxious buzzer sound here]. If it has the crappy cast-iron caliper disc brake system, same. Already, if you buy a carrier and axles, it would make no sense whatsoever to do all that and still have the old weeeeek 26-spline axles (if that crap is even still available).
Like engines, if you had, say, a 267, and it failed in some way such that it needs a rebuild, it would make NO SENSE WHATSOEVER to spend the $2500 or whatever to rebuild THAT turd, when you can get a 350 core for $200, and pour all your cash into something better. Sure, you can "repair" whatever you have now, butt if FOR THE SAME MONEY or relatively little more you can UPGRADE, it'd be foolish not to.
The point is, consider CAREFULLY what you are going to pay, and what you're going to end up with when all is said and done and the bank account has been emptied. Think REAL HARD about spending all that cash and still having something less than ideal. If you're REALLY going to bite off on all this, put your money into a better core if at all possible.
Incidentally that thing in your hand is probably the source of the backlash. Looks like one of the thin carrier shims out of a "gear install kit" (they come with 2 .100" shims for each side, then you stack up thin ones between those, to get the total thickness you need, which is usually anywhere from .230" to .260" or so). Looks like whoever put that rear together, didn't get the shims in there right, and that one got destroyed. It's not impossible that if you just got a set of carrier shims, and installed them properly, that alone might fix the noise. Problem then is, if they efffffed that up, who knows what else they knackered.
Okay, thanks for the insight guys. I will just replace the ring and pinion along with all of the bearings and shims that come in the typical kit. The car is not worth pouring money into and Its not a performance build. If that doesn't fix the whine, I may just ride it out until it annoys me enough or a major failure occurs, whichever happens first.
