Chevy Silverado and GMC Sierra Axles

cambamrjmcambamrjm Member Posts: 2
I am wondering what rear gear ratio to get. I don't do alot of towing. 4:10, 3.73, 3.42. whats the difference.


  • KCRamKCRam Member Posts: 3,516
    The higher the number, the more power and torque you will get at the wheels - this will also result in higher rpm and lower fuel economy. The lower the number, the more economical the truck will be, as the rpm will stay down, especially when highway cruising.

    kcram - Pickups Host
  • lvroblvrob Member Posts: 7
    As I understand it GM is the only company that offers a locking differential instead of a limited slip differential in 2 wheel drive models and that a locking differential is superior to a limited slip differential for traction. I'm interested in owners experience with locking differentials since off road traction is paramount to me. I understand that a locking differential can create noise & increased tire wear & am willing to live with that just as long as the locking differential is reliable and indeed provides improved traction. So I'm interested in owners experiences.

    Thought I'd add this info on differentials I found on the web, makes the GM G80 option look very desirable if you use your truck off road & not as a grocery getter:
    ""Unfortunately, limited slip differentials (LS), available as options for many 4x4 in the US are offered by sales people as "locking differentials". A confusing term because nothing on these differentials is LOCKING. They are by far inferior to a differential that is truly (manually or automatically) lockable.
    If you have to decide whether to get a "locking differential" (LS) if available as an option on your new truck I would recommend getting it, because it is still better than not having anything at all.
    To repeat: "locking differentials" are limited slip differentials that are not to be confused with differential lock!

    It seems to me, that manufacturers and dealers prefer to use the term "locking differential" over the correct term "limited slip differential" because it sounds more like the real thing - even though it is not. Is this already consumer fraud?

    Now here is a twist to the locking differential story: When Chevy advertises its trucks with an optional rear locking differential - it indeed is a differential that locks up (automatically). In the 80's it was sold as a Gov-Lok for a while named Command-Traxx and is available in some Chevy trucks as G80 option. It is not manually activated as in Dodge, Jeep and Mercedes - it locks up automatically. It is a hybrid of a clutch type limited slip unit combined with a flyweight governor that is able to lock up 100%.""

    First posted this in the Colorado/Canyon forum, didn't get much response so thought I'd post it here.
  • 1offroader1offroader Member Posts: 208
    That's true, GM has a true locking diff. The heavy duty locking diff comes standard on the 6.0L Silverado along with the Super Duty transmission. The "pumpkin", axle housing, and shock mounts are noticeably larger on it than on the standard rear diff. It also has rear ABS discs, as opposed to the standard drums - a big safety "plus".

    I've had my Silverado off road several times now and the locker works as advertised. Rear wheel spin is minimal before it engages.

    Also, on the pavement, I've had it engage on very sharp turns. You can feel it, if you know what is going on with the truck. I've also heard and felt it unlock with a very slight "clank" a few times when straightening out the vehicle after a sharp turn. This is common and expected with lockers. In fact, for a locker, it seems very quiet. Ever heard of a "Detroit Locker"? Those things sounded like an old iron gate opening and closing - but they work!

    Don't know yet about tire wear, as I only have about 8,500 mi. on the truck. I rotate my tires also. I have not noticed any unusual wear.

    IMO the locker is significantly superior to limited slip, as featured on Tundra, F-150, and Dodge. However, limited slip is smoother and quieter when engaging and disengaging. LS also slips from day one - and those little clutches do wear out over time. The locker is more robust.

    All depends on what you want. I'll put up with a small (and I mean small) amount of noise for the few occasions when it engages/disengages, for the superior "bite" I get offroad, in snow, mud, etc.

  • lvroblvrob Member Posts: 7
    Thank you,
    Good info your confirming my info. Check this Motorweek coverage, good stuff:

    I use my pickup for a beach vehicle & on back roads so off road traction is important, I'm not planning serious 4 wheeling so I'm thinking a 2 WD GM work truck with a G80 locking rear differential ~ $300 will do the job. I'll take robust & better traction & gladly put up with some noise.
    I'm surprised GM marketing isn't emphasizing this more, not everyone who buys a truck these days is a soccer mom, I really ding Edmund's & it's reviews for that especially, I don't think they even mentioned it. Kudos to GM engineering & Motorweek's coverage of this G80 Option.
  • 1offroader1offroader Member Posts: 208
    Regarding GM marketing...I haven't seen a decent TV ad yet for the new Silverado. The fact that it outsells the Tundra 6:1 (or whatever) is a bloody miracle, given the poor quality of GM advertising. That Toyota has gone to extraordinary lengths to create elaborate (and bizarre) ads for the Tundra should tell the competition it means business, even if the ads make little sense (to me at least).

    Why can't GM come up with a decent ad??? Hey Chevy, for a fee I'll help you put together an ad that will sell a bundle of Silverados to other guys like me who use trucks.

    Feel free to contact me. I'm not cheap, but I'm good!

  • lvroblvrob Member Posts: 7
  • obyoneobyone Member Posts: 7,841
    They spent all their ad dollars on those Transformers... ;)
  • cbondcbond Member Posts: 4
    what is the approximate cost to rebuild a 1-ton, dual rear end
  • obyoneobyone Member Posts: 7,841
    That would depend on who's doing the rebuilding. You or a shop.
  • cbondcbond Member Posts: 4
    at a shop
  • obyoneobyone Member Posts: 7,841
    as far as what parts need to be replaced on the rebuild. I assumed a total rebuild parts and labor in the $1200 range. Course you may find it cheaper to go to a junk yard for the parts as some shops will do that upon request.
  • cbondcbond Member Posts: 4
  • cbondcbond Member Posts: 4
    thank you, I was just feeling like I was being overcharged with an estimate.
  • eggberteggbert Member Posts: 1
    I have a 2004, 6 Litre, 2500HD Silverado, great truck, at idle there is a faint knock, not a tick, coming from the engine, a dealer said it was air being injected into the engine, I guess I question that, could it be that or a knock sensor or something else, Help please, Thanks
  • 12ozcurls12ozcurls Member Posts: 65
    It's most likely piston slap. It is common in chevy engines with the 5.3L or 6.0L from 1999 to around 2005. Heavier weight oil will quell the noise slightly, but other than that, you're stuck with it. It won't mess up the engine though, its just annoying especially on cold morning start-ups...
  • dclawman4155dclawman4155 Member Posts: 2
    I'm considering a 6" lift on my 2500. To fill the wheel wells, I'd like to go to 35's on 20" rims. Will the extra weight (100+ lbs.) versus stock (62 lbs.) cause far too much stress on the front axle stubs? I can't find outer axles (4340 steel) for the 9.25 IFS anywhere. I certainly don't want to snap an axle.

    Any input?
  • 1offroader1offroader Member Posts: 208
    The weight of the wheel/tire combo isn't the major issue, it is the larger diam., or actually the larger radius, that increases the torque stress on the front short shafts. When you increase tire/wheel size you are turning the axles against a larger radius, which increases the torque on the axles. I think you'll probably be OK since it is a 2500 with the heavier front end components, but still, you will need to be a little more careful about applying power. I would be especially careful if you have a diesel, which is a very torquy engine.

    You could get special axle shafts custom made at considerable expense, but then the ring & pinion would be the weak links, or maybe something else.

    That is the problem with major mods - you do a change, then you need to beef up something else, which leads to beefing up something else. It can be a never-ending process.

  • dclawman4155dclawman4155 Member Posts: 2
    Thanks for the input, 1 offroader. My 2500 is a 6.0 liter.
  • agdawgagdawg Member Posts: 2
    I just replaced the wheel hub assembly on my 2005 Crew Cab. The torque specs said to torque to 177 ft/pds. My torque wrench went to 150 ft pds. My question is it ok to kind of guess where the needle would be at 177 and to keep turning the torque wrench till you feel its at 177. The truck drove great to work this morning but I feel I need to go buy a new torque wrench that goes up to 177 and readjust the nut.
  • obyoneobyone Member Posts: 7,841
    That would be a good investment for future use as well unless you have a "real good feel" of what 177 ft lbs is. You don't have to buy a $500 1/2" Snap On torque wrench as a cheap one from Checkers or Sears would do.
  • maxummaxum Member Posts: 3
    Are there any known options that I might have to get better traction from my factory rear end. My truck has very low milage.
  • obyoneobyone Member Posts: 7,841
    Check it out here:

  • netcrasher96netcrasher96 Member Posts: 2
    I have a 2008 Silverado 2wd. 3000 miles. When I make a slow speed turn (Left or right) I get a pop,pop,pop noise from the rear end. I had the truck serviced at the dealer. They told me the factory used the wrong rearend fluid. My dealer serviced the rear end with the correct fluid but I am still getting the noise. Also the front tires are cupping real bad. This is a point A-B vehicle. no hauling or abuse. anyone have any ideas?
  • netcrasher96netcrasher96 Member Posts: 2
  • obyoneobyone Member Posts: 7,841
    Also the front tires are cupping real bad.

    That could be due to alignment, improper balancing, or just plain crappy General tires.

    The popping noise on turns could be a loose crossmember as obviously it's not the fluid in your rear end.
  • jeardmjeardm Member Posts: 9
    i have a 02 gmc z71 5.2 with 3:73s an 33 mud grips i want to go to 4:10s will that put back in the same power range as the 3:73s an stock size tires instead of like now it seems to bogg a little with the 3:73s an the 33s i just put on it
  • jeardmjeardm Member Posts: 9
    any input on on question 27 would be greatly appreciated
  • obyoneobyone Member Posts: 7,841
    Changing gears are often overlooked and offer an economic solution to acceleration. With 33's have you considered 4.56?
  • StrolnStroln Member Posts: 1
    I have an excel spread sheet that gives engine RPM for different size tires/different rear axle ratios/and final drive transmission ratios. All you do is enter in the information and it calculates the engine RPM. I am new to this forum so I don't know how to get it to you without an e-mail.

  • jeardmjeardm Member Posts: 9
    hey terry man that would be great if u dont kind send it to [email protected] or [email protected] that would give the perfect idea of what i want
  • wsraderwsrader Member Posts: 1
    I just installed a different differental in my 97 4x4 that the only identifing marking are on the top. It is ZWB G 281 2 20. My old differential has similur markings. Can anyone direct me to someplace that explains these markings? Thanks, wsrader
  • 2000GmcSierra2000GmcSierra Member Posts: 1
    I have a 2000 Gmc Sierra 4.8 and I want to get a posi-unit. maybe a eaton with 373 gears. but i really dont know alot about them besides that both wheel spin and the truck gets a good take off with good traction. Could anyone give me advice on what to look for when buying one and what would be a good price to have on installed. I asked a shop and they gave me the price of $1100 Installed. its an Eaton Differential, bearings, and 373 gears and the instalation. I live in Southwest Detroit, Michigan where here chevy trucks are popular and gettin them down to 11's is everyones goal. my truck is stock and it just has a k&n. my email is [email protected] if any wants to write me on there. thanks
  • hunterg10166hunterg10166 Member Posts: 5
  • hunterg10166hunterg10166 Member Posts: 5
    I have noticed latley that my rear diff will "lock" up when making turns and it sounds and feels like I am draggin the outside rear tire. This mainly happens after a fast start. I just changed the diff fluid 2 weeks ago nad inspected the oild fluid and didnt find any shavings. This is an itermittent problem. Any ideas? It is the G80 rear end too.

    Thanks, Scott
  • aserednyjaserednyj Member Posts: 2
    How do you replace a center support bearing ? 1998 G.M.C Sierra 1500 2 wheel drive. 5.0 V-8.
  • akjbmwakjbmw Member Posts: 231
    Short answer abridged from Second Edition Service Manual for '98 Chev/GMC...
    It appears that the center support bearing is a press off/press on arrangement. You do not want to use a hammer.

    Support everything to prevent excessive bending of joints.
    Make reference marks to put things back in the same orientation for balance.
    Start by removing the rear u-joint from the differential and tape the joint to keep the caps from falling off and loosing the needle bearings.
    Next remove the center support bearing bolts and remove the assembly.
    Install in reverse order.
    KEEP EVERYTHING CLEAN and re-clean before assembly.
    A longer answer involves knowing if it is a two piece or three piece assembly, if it is a Dana or American Axle propeller shaft, and how much it will cost to have it towed to a repair shop if you loose something.

    The last center support bearing I replaced was on a '70 BMW 2002. I've slept a few times since then. No pressing. Just a stubborn circlip and rubber flex joints that required compression to align bolts on re-assembly.

    Good luck.
  • aserednyjaserednyj Member Posts: 2
  • kboursekbourse Member Posts: 2
    Recently, I noticed that my '07 Sierra is making a squeaking noise when I'm driving. It doesn't sound like it's coming from underneath the hood. It sounds more like the rear axle. After, I loaded the bed with over 600 lbs of logs, the noise was more pronounced. Does anyone know what this could be?
  • kboursekbourse Member Posts: 2
  • obyoneobyone Member Posts: 7,841
    Those trucks are notorious for rear leaf spring squeak
  • sloanman23sloanman23 Member Posts: 1
    I have a 2006 GMC Seirra 1500 Short Bed with a 6.0 and 4:10 gears. My owners manual says this vehicle is not designed nor intended to pull a 5th or goose neck trailer. Why is this? Is this because of the frame won't handle it or are the afraid of damage to to the cab when making turns. Someone please help.

    Thank you
  • shanman1shanman1 Member Posts: 1
    I ve had my 2011 sierra for 6 months with 3500 kms and would have no pick up and go sluggish and make like a loud poping sound three time s then go away awhile come back continiously took it to dealer and they had to take the engine apart, had a lifter ceased so they replaced all 8 so far so good i wasnt to happy i told service guys if this happens again i want a brand new truck this is like stupid trucks not even broken in yet.
  • gmcustsvcsarahgmcustsvcsarah Member Posts: 1,964
    Hello shanman1,

    I'm glad that so far the repair that your dealership performed has held. Keep us updated if things start to go south, but hopefully that isn't the case!
    All the best,
    GM Customer Service
  • 03silverado103silverado1 Member Posts: 2
    I have a 2003 silverado 1500 4x4 with 5.3 and 86,000 miles. At highway speed I have a grinding noise comming from the front end. It seems to get quieter when I let off the gas. I can also feel the vibration through the floor and steering wheel. The noise/vibration gets much more prominent when I go over a bump. The noise does not change when turning left or right. The wheel bearings have less than 30 k on them. I`m not thinking the wheel bearing is the problem, I`m kinda thinking cv joints or input shaft bearings? I did jack it up quick last weekend and the left wheel has considerable back and forth play, but no up and down play..
  • 03silverado103silverado1 Member Posts: 2
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