Gear ratio has me confused
January 21st, 2012, 10:00 PM
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Gear ratio has me confused
Ok, so while I know what I know, I still have a lot to learn. One thing that I have NEVER been able to wrap my head around is gearing. First off, I have a 98 chevy cheyenne, and I have know idea what gears are in it. I have checked the rear end, and cannot find a sticker or plate anywhere, and the sticker in the doorjam really doesnt tell me anything. The truck has a vortec 305 in it, with an automatic transmission, and whatever gears are in the rear end. Its a little sluggish, and I'm already planning a 350 swap for it. But should I do anything to the gearing? I hear people talking about 4.10's and 3:73's and I gotta be honest it makes my head spin. I understand that it means that the driveshaft will turn 4.10 times to one turn of the axle. Where I get confused is how this will effect performance. I know it will improve torque but how dramatically? I have also heard that tire size plays a factor as well. It does not have the stock 245/75/r16's on it, the guy I bought it from put 285"75?r16's on. I guess im just asking for a little general advice and knowledge.
January 21st, 2012, 11:27 PM
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well the bigger the tire the less gas millage and could take away some power i kno in the glove box of 99 and up silverados they have a whole bunch of codes if you see one thats like gt4 i think its a 3.73 if its gt5 then its 4.10 but i dont exactly remeber if its gt or another number last night i did some research and looked up my vin number codes in the glove box it gave me my gear ratio and what type of transmission and engine i have (i already knew i had a 6.0) but it gives you good info on what your truck is theres a web site for vin decoding
if all else fails look at your rpms when going 70
2k 3.43
2.3k 3.73
2.5k 4.10
4.10 gears will have more power and less gas millage
3.43 is not as much power more gas
3.73 is in the middle
if its 3.73 its should be fine with the 350 if you want you can go with 4.10 for more power and engines tend to get sluggish as they get old a basic tune up will fix that and if your going to do the swap service the transmission for best resalts
hope this helped a little
if all else fails look at your rpms when going 70
2k 3.43
2.3k 3.73
2.5k 4.10
4.10 gears will have more power and less gas millage
3.43 is not as much power more gas
3.73 is in the middle
if its 3.73 its should be fine with the 350 if you want you can go with 4.10 for more power and engines tend to get sluggish as they get old a basic tune up will fix that and if your going to do the swap service the transmission for best resalts
hope this helped a little
January 21st, 2012, 11:35 PM
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Yes you should have codes in the glove box, the 2 98 GMCs I have at work do. But if Your gonna stick with the 285s I wouldnt worry about the gears any stock gear should be plenty, Just get a kick *** 350!
January 22nd, 2012, 12:22 AM
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Umm ok so my truck has 3.42's in it. But while I was looking through the rest of the codes cross checking them here
GM RPO Door Codes For Pontiac Firebird & Chevrolet Camaro: 1998, 1999, 2000, 2001 & 2002 Cars (PDF) | marshu.com
and here
Chevrolet R.P.O. codes.
Now when I bought the truck I was told it had a 305 in it, and under the hood, there is a sticker that says 5.0 on it. The RPO code reads L30, which is a 327. What do I listen to?
GM RPO Door Codes For Pontiac Firebird & Chevrolet Camaro: 1998, 1999, 2000, 2001 & 2002 Cars (PDF) | marshu.com
and here
Chevrolet R.P.O. codes.
Now when I bought the truck I was told it had a 305 in it, and under the hood, there is a sticker that says 5.0 on it. The RPO code reads L30, which is a 327. What do I listen to?
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January 22nd, 2012, 9:34 AM
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well a 5.0 is a 305 so if you know that you have that then thats what you got
a 327 is a 5.3 which i dont kno if they made those in that truck my cusion has a 95 gmc that has the 5.0 in it most likely what you have
sence you now know what you have if you want to go bigger than i suggest a gear change maybe to a 3.73 so when you put the 350 in you will have more power and easier to turn those big tires
a 327 is a 5.3 which i dont kno if they made those in that truck my cusion has a 95 gmc that has the 5.0 in it most likely what you have
sence you now know what you have if you want to go bigger than i suggest a gear change maybe to a 3.73 so when you put the 350 in you will have more power and easier to turn those big tires
January 22nd, 2012, 7:33 PM
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Yes, its a 305 and I will never trust an RPO code again lol. I dont really know if what I have in it are 3.42's seeing as how the code got the engine wrong. I dont think they even made a 327 that year. I know the "true" 327 engine was stopped in like 1969, the 350 sort of made it obsolete. It was a 5.4. Thats why I no longer trust RPO codes lol theres no way thats whats in it. Sooo, I think I will put different gears in it. Anyone know a place I could get a good deal?