Maintcon

99 through 05 are the only front diff that will work in the SS. Also must modify a standard 4WD center diff to work with the SS AWD system. the big changes are the spider gears in the carrier. The right side one needs to be cut to accept the axle 'C' clip or the AWD passenger axcle will roll out. Also, it is tough to find a 4:10 fromt diff from a standard 4WD truck.

Test Tools Required J 45382 Transfer Case Tester To determine if the viscous coupling is operating correctly, use the following test procedure. Testing the viscous coupling operation by removing a propeller shaft and driving the vehicle will cause the viscous coupling to fail. The test will determine if the viscous coupling is faulty from a totally locked up failure, or if the viscous coupling fluid has leaked out from being severely humped. Important The Viscous Coupling Test is very sensitive to the temperature of the transfer case. If the transfer case is very hot, the time to turn will be faster. If the transfer case is cold, the time to turn will be slower. 1. Operate the vehicle for 24 km (15 mi), or until normal operating temperatures are reached. 2. Set the parking brakes for the rear wheels. 3. Position the transmission in NEUTRAL. 4. Raise the vehicle. Refer to Lifting and Jacking the Vehicle in General Information. 5. Remove the front propeller shaft. Refer to Propeller Shaft Replacement - Front in Propeller Shaft. 6. Install the J 45382 into the transfer case front output shaft. 7. Using a torque wrench at 11 N·m (100 lb in) on the J 45382 , turn the front output shaft 90 degrees. 8. Note the length of time it takes to turn the front output shaft the 90 degrees. * If the front output shaft turns slow, and takes at least 10 seconds, the viscous coupling is operating correctly. * If the front output shaft will not turn, the viscous coupling or the planetary carrier assembly could be locked-up. * If the front output shaft turns easily, and the 11 N·m (100 lb in) cannot be obtained, the viscous coupling is faulty. © Copyright General Motors Corporation. All Rights Reserved.

If you find that your AWD Viscous Coupling is questionable, I found a company that rebuilds and sells the coupling. The company is STE Traction Control Technology and they're in Anaheim CA. They have a web site (link below) and their phone is listed as 800-883-6188. http://stecouplers.com/recharge/

If you know someone with the right scanner, you should be able to pull out the ABS fault codes through the OBDII port. This may give you a head start in locating the problem.

By any chance did you get to see the inside of the original TC to see what was broken???? Who installed the new TC???? Also, the speed senser in the TC tail shaft is for the speedometer AND is the ABS speed senser for the rear wheels. GM trucks all use a 3 channel system; 2 front channels for the front wheels and a single channel for the rears. I would inspect to make sure it is installed correctly and any plugs are connected properly. As far as the leaky seal, the seal is probably OK, pull the drive shaft and look at the condition of the front yoke (the area that contacts the seal) . You may need a 'Speedy Sleeve' if the shaft is grooved.

Agree with Bear, there aint nothin out there as far as a Tru-Trac or a Friction Plate Posi for these units. However, I did find that Richmond Gear has a product called a PowerTrax. It replaces the spider gear assembly and acts as a locker of some sort. I think (but not positive) the spiders for the 8.25 IFS are the same as the standard 8.5 10 bolt rear diffs. I do not think or would I ever suggest you install something like this in the front of anything that drives on pavement and has to negotiate a turn. Even on the drag strip, making only minor correction to keep it straight, I think it may be unstable. It would PUSH like bulldozer; e.g. keep going straight, lots and lots of under-steer. These trucks already have a tremendous amount of PUSH dialed in by the GM designers. It keeps the unknowing from falling off freeway entrance ramps, ass end first. A REAL locker in the back (manually engaged air or electric) and in general, friction plate posis, would do the same thing, keep the truck from turning. Although going straight, more power to the ground. A progressive locker, AKA Tru-Trac, AKA Torsen Differential may actually improve handling a bit by shifting torque to the OUTSIDE rear wheel (when the inside lifts in a turn) and help steer you into the turn. Just ask any of the left hander circle track boys what they think of Gold Trac diffs. Theyre just an expensive version of the Eaton Tru-Trac. Thats my 2 cents anyway.

I chose the 2000 4WD unit because it was AVAILABLE; e.g. a matter of convenience. With the exception of the spider gear ‘C’ ring groove and the lack of a carrier adjusting nut roller bearing on the right side (long axle side), the center section of 1998 through 2006 AWD and 4WD front differentials are the same. For me, rebuilding the bone yard unit was easier than removing the one in the SS, hoping major components like aluminum housing and carrier were O.K. or repairable, disassembly, ordering parts, waiting on delivery and hopefully getting it back together and out of my garage in a short period. With a rebuilt unit I could work on it at MY convenience and still have the SS at least semi drivable. Also, I plan on rebuilding the original differential and keeping it around; “just in case”.

Well we got the new front differential installed last night. 3 hours flat, just rolled the truck up on 4X4’s pulled the original and installed the rebuilt 2000. You can do this WITHOUT dropping the steering arm or tie rods, just remember to turn the wheels fully left. If you look at picture 14 and 15, the 2005 unit is positioned next to the replacement. I left the long axle installed during removal so that I wouldn’t be fighting gear oil running down my arm at the same time as wrestling the gearbox out of the truck. Picture 16 is the ‘hole’ under the truck where the front differential resides. During installation, I installed just the center section 1st and then installed the long axle. It made it a lot easier to ‘bench press’ the unit back into the mounts with just 2 ends to aim and worry about the 3rd leg later. Pictures 17, 18 and 19 are the best, they show what ‘usta-be’ a carrier bearing. What’s interesting is that the rollers are on the WRONG side of the carrier adjusting nut. The ‘goo’ you see surrounding the bearing pieces is the consistency of past; a ground metal gear oil past. There won’t be much salvageable I’m afraid. I’ll take pictures and re-post once I get the thing apart so all can admire the carnage. Also from pictures 18 and 19 you will note that there is no roller bearing installed in the carrier nut. On the 4WD units, there is a small roller bearing installed in BOTH carrier adjusting nuts to support the stub axles. On the AWD units, the long axle is supported by the spider side gear and the bearing at the end of the long axle housing. If you do install a roller bearing here it wont be supporting anything because the long axle is ‘undercut’ (smaller diameter) just past the splines. So the last difference between the 4WD and AWD differentials is revealed; no carrier adjusting nut roller bearing on the long axle side. The best part; when I road tested the rig – NO NOISE, quite as morgue. Hopefully it will stay that way. We’ll change the oil at 500 and 1000 and hope for the best after that. As far as dollar savings by doing this yourself; in the $1200 dollar range based on $2000 for a dealer or transmission shop completing the work or, about $300 to $500 if you were to buy a rebuilt unit and install it yourself. Link to Pictures; http://picasaweb.google.com/102438165407566385617/SSDifferential#

Finally, got the beast assembled and ready to swap out. Setting the pinion depth only took THREE tries. Spent Christmas day and the day after fussin with the thing. Anyway if you click on the link below it will take you to a series of pictures. Pictures 8 and 9 show the ring gear pattern from too many shims and picture 10 and 11 show what I consider a good pattern, especially on the drive side. The coast side on the final adjustment is still a bit low but I think shell be O.K. Picture 12 shows how I was pressing the pinions back out of the housing; pretty crude but it gets the job done. I also used this arrangement with a Harbor Freight bearing splitter to get the pinion lower bearing off the several times needed to get the correct shims in place. I had bought the Porta-Power several years back for industrial fan work and Im grateful I kept it around for this challenge. Picture 13 shows the beast fully assembled and ready for installation. A couple of assembly notes; 1) The spider gears need to be installed before final installation of the ring gear; the pin that goes through the carrier will not fit with the ring gear installed. 2) When adjusting the backlash and setting the final torque on the carrier adjusting nuts, a second set of hands is helpful. It youre by yourself, it will be like wrestling a pig to hold the thing while tightening up the carrier adjusting nuts. 3) You will NEED to purchase a spanner tool to tighten the carrier adjusting nuts. Do not believe the guy who says; just knock then around with a screw driver. Im glad I bought one earlier or Id be waiting another week to finish the job. 4) A ½ inch electric impact wrench will eventually smack down the pinion nut against the crush sleeve to get the final pre-load on the pinion, itll just take a while. http://picasaweb.google.com/102438165407566385617/SSDifferential#

The new spider gears were delivered yesterday and this evening I did an initial assemble of the gearbox just to see where the pinion landed on the ring gear. Remember from the last post that I had reused the shim from the 2000 4WD differential. Well it looks like I need to ADD shims. The reason, the pinion is riding high on the ring gear. If you follow the link to the photos, you will note that the scrub marks on the bluing (yellow goo) are high on both the coast and drive side of the gear tooth. This means pressing off the front pinion bearing and adding shims. Now, just in case I hose up that bearing (remember press off and heat/smack on) I went ahead and bought another Timken cone assembly. This is the roller part of the bearing. Since the cup was never used, a new cone assembly is all that is needed; e.g. cups and cones sold separately. Timken Front Pinion Bearing P/N; M802048 for the cone and M802011 for the cup. Picture 6 shows the Coast side pattern and picture 7 shows the Drive side pattern. http://picasaweb.google.com/102438165407566385617/SSDifferential#

I had removed and torn down my transfer case this last summer. Did it in the street in front of the house. It really is a straight forward job; approximately 1.5 hours to remove, an hour for transfer case R&R and another 2 hours to get her back in. Had 2 wheels up on the curb and 2 wheels on 4X4’s and that’s all the height needed. Field stripped the transfer case on a pair of saw horses in the driveway. The hardest part about reassembling the thing is locating the oil pump suction tube. The reason I removed mine was the front drive shaft output shaft bearings (transfer case lower shaft bearings). An incorrectly installed seal at the factory allowed water into that bearing. Lots of noise right under your butt. Anyway, the case comes apart easily and the viscous coupling pretty much falls out. I would say that anyone that can hold a wrench can accomplish this job. And if you can’t figure it out, take the ‘box of parts’ to your transmission guy to reassemble then reinstall the transfer case yourself. My last post gave you a source for a new viscous coupling, STE Traction Control Technology, and the other parts needed are the intermediate adaptor gasket and a tube of RTV form-a- gasket (I like the blue ‘goo’). I got the adaptor gasket from the dealer. As far as bearings and chain, if they aint makin’ noise, reuse them. Just do a good inspection of components once you open the case. Anyway, I think you can do this job and save yourself a bundle. Good Luck

Over this last weekend, finished tearing down the bone yard 4WD diff. The only parts I’ll be using from the 4WD unit are the carrier adjusting nuts/sleeves, the carrier, the aluminum housing, the drive shaft yoke, the pinion shim and the left side stub axle. All other parts will be new. Another pointer on disassembly, besides the left handed ring gear bolts; the carrier adjusting nuts are screwed into sleeves pressed into the side of the aluminum housing and one would assume removal would involve bending the lock tabs out of the way and unscrewing the nuts. Not so, just ‘knock’ them through from the outside in; the sleeves are not pressed in all that tightly. From the pictures, you will note that my new pinion shaft is sitting next to my holiday Cinnabons (picture 2). The carrier is sitting under the Cinnabons. Freezing the shaft and the carrier overnight shrinks them down a bit and after cooking the new bearings at 400°in an old deep fryer (picture 3), the bearings more or less slip right on; in theory anyway. As the brass and the hammer in picture 4 suggest, you still need to get a bit medieval on the unit to ensure the bearings are seated. Picture 4 is the new pinion with the front bearing installed with the shim from the 4WD unit. Picture 5 shows the pinion installed ‘without’ the crush sleeve for the initial backlash and pinion depth adjustment. To see the pictures, click on the following link; http://picasaweb.google.com/102438165407566385617/SSDifferential#

If you find that your AWD Viscous Coupling is questionable, I found a company that rebuilds and sells the coupling. The company is STE Traction Control Technology and they're in Anaheim CA. They have a web site (link below) and their phone is listed as 800-883-6188. http://stecouplers.com/recharge/

Just a quick update on the progress of my 4WD to AWD front diff conversion. Got all of the parts except the new spider gear set. Should be here early next week. Besides the parts listed in previous posts, I also ordered and received a carrier adjusting nut spanner. Got it from Seven Springs Customs for $49.95; P/N YTA08. Also, once I had looked through the Master Bearing Kit from drivetrain.com noted that the carrier adjusting nut lock tabs and the axle C rings were not included. I picked these up at the local Chevy dealer. GM Part numbers are 15588312 for the lock tabs and 26056600 for the C rings. I finally got the 2000 diff fully disassembled and learned a new lesson and that is; another oddity on these front GM diffs that any of you would be builders should note is that the ring gear bolts are LEFT HANDED threads. I kinda found this out the hard way. To remove the carrier and front pinion bearing, I took the parts to a friend of mine who is the shop manager of a local electric motor rewind shop; they have a pretty good size arbor press. To get the carrier to fit on the press we had to remove the ring gear. So we chuck up a ¾ inch impact gun and commence rattling off the bolts. We stripped the threads on all 10 bolts. Once we smacked off the old ring gear and pressed off the bearings I took the whole mess home. Once at the house, I was messing with the new ring gear and ring gear bolts (that came with the bearing kit) and after a couple of trys of righty tighty and no thread engagement, I tried a quick turn to the left and the bolt started to suck itself into the ring gear. Wah La, solved the stripped bolt mystery!!! Left handed threads. Ill take a few snap shots of the 2000 differential as its assembled and I update the posting.

It is pretty funny. I've been listening to front of this truck growl, howl and wine for about 2 years now. Been collecting info on the front diff and transfer cases for a while not knowing exactly when or where the thing would finally grenade. I had it pretty much planned out what I wanted to do, e.g. rebuild a used 4WD unit. However, did not expect the spider gear ‘C’ ring issue. Now everyone is informed, if you’re going to convert and early 2001 or older 4WD differential to AWD, you’ll need to order a set of spider gears that have grooves for the ‘C’ ring. Also, verified that the AAM 74045936 P/N for the spider’s is correct (‘C’ ring grooves). I had gone through the transfer case on my 05 this last summer. At the factory, an improperly installed front drive shaft seal allowed water it into that lower bearing causing it really make some noise. Replaced both lower bearings on the front drive shaft output shaft and replaced the drive chain, just because. Next year I plan on rebuilding the front diff I’m pulling out of the SS and keep it around as a spare or maybe changing to 3:73 gears. If I went to 3:73 gears, this would give me an excuse to tear down that crappy G80 in the back and installing a Detroit Tru-Trac (also by Eaton). The Tru-Trac would cure a good part of that god awful push that’s dialed into most trucks and made worse by cheap ‘friction’ posi’s. The only reason for the 3:73 gears would be a bit better economy. Gotta’ love the SS; most other vehicles would have been traded by now if they gave me this much headache.