speedfrk73z

Because you are going to remove/replace the IFS yourself. Go to the AWD/Diff/Trans section and search for "front end dead". It has all of the torque specs needed to install the IFS.

The diff unit in the IFS does make some noise when turning right or left. This sound is normal. What you are hearing is the spider gears working inside of the carrier unit. When turning to the right the left front tire is rotating faster than the right tire. The spider gears inside the unit are allowing for the differential (hence the name diff) in speed. Now most open style diffs are quiet, but for some reason these IFS units make some noise. The noise that you hear sounds very much like a posi rear diff unit that uses clutches (with spring pressure). Now if you are going straight, and you hear noise you have a problem.

If you hear any grinding noise you have a bearing issue. You may not see the metal shavings on the plug until you drive it more. The oil discoloration will come later after you put some more miles on it. I would bring it back to the shop and let them tear it down. If they are honest they will admit it has a bearing problem and repair it for you.

After giving this issue some thought. I believe that this problem is related to resistance. If you had a short in the wiring the fuse would blow immediately. I think that the trailer might have too many running lights on it. It could be the combination of the length of the wiring in the truck combined with the wiring and lights on the trailer. You might try removing a few of the bulbs on the trailer that really aren't needed when towing with this vehicle. Example: Side lights. Also if this fixes the problem you should consider replacing the lights with LED lights. They are more efficient and use less power to run. Again I am assuming the trailer is using the old bulb type lights. If the trailer is already using LED lights you should disconnect a few side lights. The same logic applies to LED lights also. Please post the fix here. Everyone can benefit from the resolution.

Yes as long as the housing is for the same year/model of your truck. You can have the gear changed to 4.10.

1. You need a spanner socket wrench, torque wrench, and a dial indicator. You also need new locking tabs for the carrier nuts. 2. Then you have to turn the carrier adjustment nuts (using the spanner socket) until the backlash (space between the pinion and ring gear) is set to 0.13-0.18 mm (0.005-0.007 in) (Using the dial indicator. Set up on the pinion yoke). 3. Then use the torque wrench to preload the bearings to 75 Nm (55 lb ft). 4. Recheck the backlash setting. If its not in the range 0.13-0.18 mm (0.005-0.007 in) re-adjust. 5. Once you are happy with the backlash setting you can bend the locking tabs over the adjustment nuts. 6. Put the diff back together 7. See post "Front end Dead" for all torque settings. 8. Good Luck!

The leaking of oil from the cover support bolts are a common issue with all girdle covers. I always use Permatex Locktite PST thread sealant 592 (Teflon paste). The good news is that you don’t have to drain the fluid. All you have to do is back the bolts out about 1/2 inch, and spray some brake cleaner on them. Then you can apply the sealant and re-torque the bolts. Wipe the excess off and tighten the locknut. Also most girdle covers do not add volume to the diff housing. Your factory oil filling capacity should be followed.

After reading all of the posts here I would suggest checking two things. First: Check all front end parts (example: ball joints, bushings, shocks, etc.) Second: Have a different shop check the alignment again. I have experienced some strange front end shimmies when experimenting with alignment settings (drag race settings) on my z28 Camaro. The best setting always ends up being the factory settings. The new alignment machine you mentioned may not be calibrated correctly, or the mechanic may not know how to use it yet. Anyway those are my suggestions. Good luck, and post the fix here for us.

I have to agree with you there fireman31. There will be differences in brake pad wear only. But what I said about brake pad squeal applies to any disc brake vehicle.

As long as your brake pad is not worn to the wear indicator you can reuse the old pads. Squeaking occurs because of vibration that occurs between the back of the break pad and the brake caliper. If you pads are good all you have to do is remove them and clean the backs of the pads using brake cleaner, and wire brush to get off the heavy crud and or rust. Then apply an anti squeak like Permatex 82017 disc brake quiet. Let it cure per the manufacturers directions, and reinstall the pads. The squeak will be gone. My factory brakes have 73,000 miles on them and they are still going. If you brake hard I’m sure the pads will not last as long as mine.

Waltsum3, that tru-cool max transmission cooler looks like a nice upgrade to the stock unit. I do some towing, and running lower transmission temps will extend its life. Can you see a big change in operating temps? Painting the cooler will have an affect on its cooling efficiency. I would contact the manufacturer, and ask for their suggestion on what kind of paint you can use. They might tell you not to paint it. 10.90@124mph

Nevada79, I have the torque specs on the 8.25 IFS for everyone I'm missing the ring gear to carrier bolt torque. If you could look that up and post it for everyone it would be appreciated. 8.25 IFS Torque Specs: Inner axle housing nuts (Passenger side axle tube): 100 Nm (75 lb ft) Diff carrier upper mounting bolt and nut: 100 Nm (75 lb ft) Diff carrier lower mounting bolt and nut: 100 Nm (75 lb ft) Axle shaft to drive shaft bolts: 79 Nm (58 lb ft) Vent Hose Connector: 28 Nm (21 lb ft) Drain and Fill plug: 33 Nm (24 lb ft) Diff carrier case bolts: 47 Nm (35 lb ft) Axle tube to diff case: 40Nm (30 lb ft) Backlash: 0.13-0.18 mm (0.005-0.007 in) Diff carrier adjuster nut (Preload): 75 Nm (55 lb ft) Pinion rotating torque new bearings: 1.7-3.4 Nm (15-30 lb in) Pinion rotating torque old bearings: 1.0-2.3 Nm (10-20 lb in) Rotating torque for diff and pinion assembly new Bearings: 3.4-6.2 Nm (30-55 lb in) Rotating torque for diff and pinion assembly old Bearings: 2.8-5.1 Nm (22-45 lb in) Ring gear to carrier bolts: (I could not find this one)

VR4Rob, I ended up with the unit from Zumbrota Bearing and Gear for 750.00 plus shipping. The locking tab in located on the carrier preload nuts. Remove the IFS unit from the truck. Then remove the axle shaft on the driver side(Short side) of the IFS. Then remove the axle seal. You will then see the carrier preload nut. If the tab is still working it will be bent over the preload nut in between the raised notches of the nut (It keeps the nut from turning). If it is not there you will see the broken tab behind the axle seal when you remove it. The passenger side is more difficult to get to. You have to remove the axle. Then unbolt the axle tube, and remove it. Then you can see the carrier preload nut, and tab. I also have all of the torque specs for the 8.25 IFS (internal, and mounting) if you need them I can post them for you. Just an FYI. If you have a good working diff, and you change the oil in it at least every 25,000 miles. When you pull the plug to drain the diff the oil should be clean, and clear. It will have some metal shavings. The oil should not be black like the pictures you posted.

Hawkman, I have used some of Jaspers products, and I'm not impressed. I hope you are right about them. Only time will tell. Don't forget to post here if you have any issues.

VR4Rob, you definitely have the same problem. That is quite a bit of metal in the oil. In my case I believe that if the locking tab would not have broken the IFS would still be functioning fine today. After inspection of my dismantled unit not every part in the unit was destroyed. It needed all new bearings, and seals. The case, carrier, axles, and side (spider) gears, were all fine. I did not want to spend all day rebuilding it, and purchasing all the tools to do it correctly. In the end I would have spent close to the 750.00 in tools, and parts. So I decided on the rebuilt unit. If I have any issues with the rebuild unit I'll post it here. 10.90@124mph

Nevada79, I had exactly the same problem with my IFS. When the tab broke (driver’s side) it allowed play in the carrier bearings. Over time it beat up the carrier bearings, and the noise started. I bought my truck new in 2003. It now has 73,000 miles on it. I just replaced the IFS. After doing some research on line I found a few solutions that could help everyone on this site. I decided to go with a rebuilt unit from Zumbrota bearing and gear (http://www.zbag.com) for 750.00 you get a completely rebuilt unit including axles, and seals. They charge a 350.00 core charge, and shipping both ways for 120.00. It comes with a one year unlimited mileage warranty. I installed the unit myself in about 1.5 HRS. The rebuilt unit is quiet and smooth. I also considered purchasing a unit from (http://www.justdifferentials.com/). They sell a rebuilt unit that comes with a new case, but no axle shafts or passenger side axle tube for 1000.00 plus shipping. No core charge. They do not want your core. It also comes with a one year unlimited mileage warranty. Jasper is smoking crack! They want 1900.00 plus 500.00 core deposit, and shipping. It also comes with a three year 100,000 mileage warranty. (http://www.jasperengines.com/differential-rear-axle.htm) The GM factory discontinued selling the (Complete) replacement IFS for some reason. Cost was 1264.00 (New). I could not find a leftover anywhere in the US.