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old 11-03-2009 08:50:24 4.245.2.54 812456 Report to Moderator	Ok so I think I found where the piece came from which is bad news since they are part of the pinion gear. So is there any way to know the gear ratio of a rear end with out opening it up and counting teeth?? I have 1 half ton rear end from a 1969 but know I would need to use my housing with the ring and pinion from it. I also have 2 3/4 ton rear ends and if one of them would be the same gear ratio as my 1/2 ton one I would just swap the whole rear ends if they will bolt in that is. I figure if I can put the 3/4 one in that would give me better/bigger brakes and also a heavier rear end. Thank for any help you can give me [Reply]   [Send Email]
Clefus 11-04-2009 07:34:07 70.211.84.149 812722 Report to Moderator	Re: O/T Chev truck rear ends in reply to old, 11-03-2009 08:50:24   If you swap a heavier rear in you may need an adaper u-joint for your driveshaft... As long as you get the same ratio, you could get a rear from another make as long as the spring perches are the same width....different mfgs used Dana over the years also.... Still trying to find a reasonable Dana 60 or GM 14 for my mudbog truck...have a Dana 44 for the front...   [Reply]   [No Email]
schmuck 11-04-2009 00:05:29 173.184.205.109 812666 Report to Moderator	Re: O/T Chev truck rear ends in reply to old, 11-03-2009 08:50:24   Keep one tire on the ground so that it cannot spin. Mark the pinion and housing with chalk or a paint stick. Turn the tire that has been raised TWO full turns and count the pinion revolutions. This DOES work.   [Reply]   [No Email]
schmuck 11-04-2009 00:08:35 173.184.205.109 812667 Report to Moderator	Re: O/T Chev truck rear ends in reply to schmuck, 11-04-2009 00:05:29   I forgot to say, if the differential is a limited slip or posi-trac, this WON'T work.   [Reply]   [No Email]
Jeff B. 11-03-2009 18:36:08 69.20.162.151 812628 Report to Moderator	Re: O/T Chev truck rear ends in reply to old, 11-03-2009 08:50:24   Usually they will stamp the ratio or tooth counts of the ring & pinion right on the side of the ring gear. Spin it around while it's still in the housing and you will find a GM part number followed by the ratio or tooth counts, and then the date of manufacture. If the cover bolt counts are the same e.g. 10 bolt or 12 bolt rear end, then the stuff will swap.   [Reply]   [Send Email]
rustyfarmall 11-03-2009 14:31:58 209.152.78.140 812563 Report to Moderator	Re: O/T Chev truck rear ends in reply to Nancy Howell, 11-03-2009 08:50:24   There should be a bunch of those 3:08s out there somewhere.   [Reply]   [No Email]
jdemaris 11-04-2009 05:42:58 72.171.0.149 812694 Report to Moderator	Re: O/T Chev truck rear ends in reply to rustyfarmall, 11-03-2009 14:31:58   1/2 ton 3.08s are all over the place. I have over two dozen sitting out in my field, in 4WD Blazers, trucks, and Suburbans. A few older 12 bolts in late 70s stuff, but mostly 10 bolt from the 80s. I've never come across any 3.08s heavier axles, 14 bolt and up. All mine are 3.73 and 4.10.   [Reply]   [Send Email]
old 11-03-2009 15:11:17 4.245.7.209 812567 Report to Moderator	Re: O/T Chev truck rear ends in reply to rustyfarmall, 11-03-2009 14:31:58   Ya local salvage yard has one for $350 but then a new one is also at least that much and that is just for the ring and pinion set so guess no matter which way I go it is going to cost about the same   [Reply]   [Send Email]
rustyfarmall 11-03-2009 14:05:46 209.152.78.140 812555 Report to Moderator	Re: Just count the turns . . . in reply to mjbrown, 11-03-2009 08:50:24   Yes, the driveshaft will make more revolutions than the axle.   [Reply]   [No Email]
jdemaris 11-03-2009 11:47:01 72.171.0.139 812530 Report to Moderator	Just count the turns . . . in reply to old, 11-03-2009 08:50:24   Just jack one wheel off the ground, put the trans or transfercase in neutral, and turn the one wheel - and see how many turns it goes to make the driveshaft turn once. Very easy to do. If the wheel turns 1.8 revs to the driveshat turning once - it's a 3.73 ratio. It if the wheel turns 1 3/4, it's a 3.42 ratio. If the wheel turns 1 1/2 turns, it's a 3.08 ratio. Note that if one wheel won't turn on it's own, you've probably got a posi-rear and you'll have to get both in the air. Also the math is different. If both rear wheels turn together: Wheel turns 3.7 turns to the driveshaft once - 3.73 ratio. Wheel turns 3.4 turns - 3.32 ratio. Wheel turns 3 turns - 3.08 ratio.   [Reply]   [Send Email]
PJH 11-03-2009 13:40:50 71.186.102.201 812554 Report to Moderator	Re: Just count the turns . . . in reply to jdemaris, 11-03-2009 11:47:01   Isn't it the other way around JD? I think the driveshaft makes several revs to one wheel rev - or am I confused??? Paul   [Reply]   [No Email]
jdemaris 11-03-2009 14:12:26 67.142.130.26 812557 Report to Moderator	Sorry about that . . . in reply to PJH, 11-03-2009 13:40:50   Yes, I was in a hurry and stated all backwards. Not an uncommon event for me. E.g. a 3.73 ratio is 3.73 turns of the driveshaft to one turn of both back wheels (if turning together . . . or 1/2 that if an open differential with only one wheel turning.   [Reply]   [Send Email]
BCnT 11-03-2009 10:35:18 75.106.0.52 812498 Report to Moderator	Re: O/T Chev truck rear ends in reply to old, 11-03-2009 08:50:24   your local dealer can tell you from the vin #   [Reply]   [No Email]
dlplost 11-03-2009 10:26:16 69.205.132.94 812495 Report to Moderator	Re: O/T Chev truck rear ends in reply to old, 11-03-2009 08:50:24   "And no tag on my bad rear end" How about a tag on the front?   [Reply]   [No Email]
old 11-03-2009 12:26:05 4.245.1.139 812537 Report to Moderator	Re: O/T Chev truck rear ends in reply to dlplost, 11-03-2009 10:26:16   I didn't think about that. Of course I still have to figure out the gear ratio on the donor   [Reply]   [Send Email]
trucker40 11-03-2009 10:18:20 69.150.232.52 812492 Report to Moderator	Re: O/T Chev truck rear ends in reply to old, 11-03-2009 08:50:24   Well on the 3/4 ton you would need to put the master cylinder and rod that pushes it off of the 3/4 ton to get the better brakes maybe.To get an idea of what a ratio is mark a wheel,turn it all the way around and count how many time the yoke turns.If it turns a little over 4 turns thats a 4.11.A little less than 4 turns is 3.90 or 3 and a half would be 3.50 3 and a third 3.30.Cars would be higher except maybe a station wagon.Just about any ratio could have been ordered or changed.3/4 would probably be lower than 1/2 ton,especially if it came out with a 6 cylinder engine.If it came with a v8 it might be higher than a 6 cylinder but still lower than your 1/2 ton.There might not be an exact match between 3/4 ton and half ton,but I think I read somewhere that you want the faster or higher rear end on the front of a 4 wheel drive.I dont know how much difference you can get away with,not much probably.Like 4.10 on the front and 4.11 on the back.   [Reply]   [No Email]
chevytaHOE5674 11-03-2009 09:52:19 71.13.222.247 812481 Report to Moderator	Re: O/T Chev truck rear ends in reply to old, 11-03-2009 08:50:24   Look in the glovebox for the RPO code sticker. If its still legible there should be some that start with Gxx, Like G80(posi traction), or GU6 (3.42 ratio) etc. Post up what you find.   [Reply]   [No Email]
bradk 11-03-2009 09:26:27 72.15.38.102 812474 Report to Moderator	Re: O/T Chev truck rear ends in reply to old, 11-03-2009 08:50:24   Count the ring gear teeth,then the pinion teeth.Divide the ring number by the pinion number and you have your ratio. Example.37 ring teeth 9 pinion teeth.37 divided by 9 equals 4.11   [Reply]   [Send Email]
Bill in IL 11-03-2009 09:19:36 131.43.10.190 812471 Report to Moderator	Re: O/T Chev truck rear ends in reply to old, 11-03-2009 08:50:24   Chevy used to put the options on a sticker in the glovebox if its still in there. Sometimes in code sometimes not. May have to web search to find the codes meanings.   [Reply]   [No Email]
rustyfarmall 11-03-2009 09:13:44 209.152.78.140 812469 Report to Moderator	Re: O/T Chev truck rear ends in reply to Phil in Pa, 11-03-2009 08:50:24   Rich, the V.I.N. plate on the dash, or maybe it's on the door jamb, will tell you exactly which axle you have, but it is in code, and you will need to decipher that code somehow. Also, sometimes you can find a "build" sheet tucked into the back of the seat, but yours is probably gone by now.   [Reply]   [No Email]
glennster 11-03-2009 08:58:27 76.217.101.141 812460 Report to Moderator	Re: O/T Chev truck rear ends in reply to old, 11-03-2009 08:50:24   there may still be a tag on the rear end, bolted to the pumpkin, either on the fill plug or the rear cover bolts. if not, kind of a down and dirty way, but if you put a mark on the axle flange, then spin the yoke where the driveshaft hooks up, count the revolutions of the yoke to get one full revolution of the axle. say you turn the yoke 3 and 3/4 turns to get one revolution out of the axle, its about a 3.75 ratio. not real exact, but its a ball park.   [Reply]   [Send Email]
old 11-03-2009 09:11:02 4.245.2.54 812464 Report to Moderator	Re: O/T Chev truck rear ends in reply to glennster, 11-03-2009 08:58:27   Ops I left out the fact this is a 4X4 truck so the 2 axles have to match or I could end up with a truck that would tear its self apart if put in 4 wheel drive. And no tag on my bad rear end and sure wish I knew what the numbers I see on the ring gear mean   [Reply]   [Send Email]
carman870ky 11-03-2009 11:22:35 66.161.151.18 812521 Report to Moderator	Re: O/T Chev truck rear ends in reply to old, 11-03-2009 09:11:02   There should be an 8 or 9 digit part # then something like a 41 followed by, say a 16. Divide the 16 into 41 and you get the ratio. In this case a 2.56 Your #s WILL be different. This is just an example.   [Reply]   [No Email]
old 11-03-2009 14:12:50 4.245.5.71 812558 Report to Moderator	Re: O/T Chev truck rear ends in reply to carman870ky, 11-03-2009 11:22:35   Well other then the fact the smaller number is first then the bigger one you are right. My ring gear has on it 13:40 which as per the Chev dealer makes it a 3:08 rear end so at least I know why I get so good on gas for what the old truck is   [Reply]   [Send Email]
schmuck 11-04-2009 00:12:40 173.184.205.109 812668 Report to Moderator	Re: O/T Chev truck rear ends in reply to old, 11-03-2009 14:12:50   I had a 3.08 rear end in a 2-wheel drive 1/2 ton. Pulled it out and put a 3.73 in it. HOLY CRAP! You would think I just pulled out the small block and put in a big block. Course, it wouldn't run 55 MPH in first gear anymore either ...   [Reply]   [No Email]