This Old Suburban-transfer case, rear axle, rear springs

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by Foy, May 22, 2003.

  1. Foy

    Foy Registered Member

    Oct 28, 2002
    Likes Received:
    Raleigh, NC
    Gents- New here, but long time Chevy truck owner/user. Family carryall is '90 Suburban K1500 Silverado, 350 (original), 700R4 (rebuilt), and stock running gear, all with 180,000 mostly in-town miles. From searches here, it appears that the transfer case is a chain-driven NP 241. I've seen reference to a 241c but can't figure out what that is. What I'm interested in is: I'm getting some noise that sounds like a trans case chain whine. I've got no fears about pulling the case, but have never rebuilt one. Is this a project requiring much in the way of specialty tools,do-able by an average wrench with a good bench to work on and ability to follow instructions? The other thought is just replacing it--around here there are many (most?) Suburbans which have rarely, if ever, had the trans case engaged. If swapping out is looked at, what year range Subs and/or other vehicles have the same trans case and would bolt right up?
    Similarly, I've got some serious rear end gear whine. The rear axle is stock with a limited slip. If I have to replace the ring and pinion, could I just find another entire carrier (with the same 3.73 ratio, of course) that's also limited slip? Once again, what year Chevy Subs, Blazers, or pickups would have these gearsets/carriers?

    The old girl has a serious driver's side lean to the rearward end. Searching here on "rear springs" tells me that the right front could be the culprit, but the tape measure work and inspecting I've done tells me that it's more likely the driver's rear pack sagging (or sagging worse than the passenger side). What do you suppose a spring shop would charge to install a new set of rear springs--both sides--with new bushings, u-bolts and such. I have no interest in re-arching. Unless times have changed over the last 25 years or so, re-arching doesn't last long.

    Lastly, any recommendations on shop manuals? I have a Haynes POS "pamphlet" looking manual, but figure a Chiltons or OEM GM-published manual is what I really need. Any suggestions appreciated.

    Project This Old Suburban is under way to provide the youngest member of my family with daily driver wheels. We've had her for 7.5 years and have put 100K of the 180K total on her. Wife, self, and #1 son have all had the pleasure of using her for a daily driver. The young one will be driving to and from school, to the mountains (snow, 4WD use) and running the beaches on the Outer Banks (surf-fishing and surfing) for a couple of years, if not more, so we'd really like to spruce her up a bit.

    Any assistance much appreciated.

  2. sled_dog

    sled_dog 1 ton status

    Sep 3, 2002
    Likes Received:
    Austin, TX
    wow thats a lot of crap crammed into one topic. Umm I am suffering from a bad headache right now so I will just deal wtih the gears and tcase. Is the tcase whine just in 4wd? Cause chain drive tcases just plain whine, its what they do. My 208 does it and every person wtih a chain drive i know theirs do too. I am guessing you are hearing a whine that you understnad isn't normal. Never rebuilt one myself but a similar 241 from 89+ K5 or suburban should fit(till 92 then was ifs). You were correct it is a 241. And as far as the rear goes maybe you should looke for a newer 2500 6 lug pickup. 3.73 gears are common in 2500 LD pickups with trailering package and the 14 bolt semi floater will be stronger than your 10 bolt.
  3. BlazerGuy

    BlazerGuy 3/4 ton status

    Apr 20, 2000
    Likes Received:
    [ QUOTE ]
    Lastly, any recommendations on shop manuals? I have a Haynes POS "pamphlet" looking manual, but figure a Chiltons or OEM GM-published manual is what I really need. Any suggestions appreciated.

    [/ QUOTE ]
    The Chiltons manual is pretty much the same thing as Haynes. I would recommend checking out or Ebay for a factory shop manual.
  4. BowtieBlazer

    BowtieBlazer Diesel Powered Premium Member

    Jul 15, 2001
    Likes Received:
    Baton Rouge, Louisiana
    T-case rebuild isnt much of a pain at all:
    T-case rebuild post from awhile back

    What you will want to do is if I remember correctly exactly this:

    -- Drain the fluid.

    -- Diconnect the speedo cable

    -- Remove the TC from the truck.

    -- Point the rear out put shaft towards the ground. (I dont have a vice big enough or any special tools I just put a board beneath it to keep from damaging the outputshaft. Maybe you have a better way to support it. I'd find a helper to hold it for you.)

    -- unbolt the t-case at the halves

    -- ease them apart they may be difficult to seperate at first whatever you do don't use a screwdriver to break them apart this will damage the matting surface. If you must use something on the oblong ends of the t-case there is a sort of lip by the outside bolts you can pry there gently.

    -- pop goes the weasel its apart!

    -- you sould be able to slowly part the two peices looking inside so that if anything comes apart and the chain comes off you will know where it came from. (likely the chain will want to stay attached to the front output shaft)

    -- Clean both matting surfaces well and make sure they are nice and clean and used BLACK? RTV to put they back together. It doesn't take much to seal the case as long as you have a clean matting surface on both sides and torque all the bolts back in a circular pattern to 35? ft/lbs. Seriously I might have used a bead of RTV as 1/3 as wide as the surface straight down the center of the matting surface and looping around the outer holes. Don't put too much because you don't want lots of excess dripping into the internals of your t-case

    Its not very difficult and don't be scared...I never thought I could rebuld a T-Case myself. My mechanic buddies were scared to help because as they put it transfer cases and transmissions are in their own world apart from the auto world. I said the heck with it. Followed my hanes manual and took my time paying attention to what went where...I now could about build one in my sleep. I can just about visualize it all as I explain. The only problem you may have is with teh front yoke. I believe I removed it first and you may or may not have to depending on how stuborn the chain is inside. If you do remove it once again torque on that front output nut is crucial at 120ft/lbs. Good Luck and have fun!
    P.S. I should probably tear my 208 apart and rebuild it borrowing a digital camera along the way. Then do a writeup. I get lots of t-case related ?'s and its not all that bad...You'll see. While you are at it you may as well clean the little magnet inside the case. Its circular and will look like a blob of mettalic gunk on the rear output shaft side.

    As far as the rear springs if you are buying new ones, why not a small lift spring 2" - 4" they are the same price if not cheaper, even for practical uses a 2" lift would allow room for a slightly bigger snow tire or 4x4 use tire without changing any of the handling characteristics

    Oh yeah! Welcome to the site! /forums/images/graemlins/thumb.gif /forums/images/graemlins/thumb.gif /forums/images/graemlins/thumb.gif

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