possible bad rear diff? need advice

[strutaeng]

ok. I paid for the unit. They are gonna try to get it to me before Christmas, but he said def by the 26th. Do you guys have any tips/tricks I need to know? what else should I replace while I'm doing this? U joints? Bushings? any info would be helpful. Thanks in advance

I believe the u bolts need to be replace. U joints probably a good idea too.

New fluid on the new differential. Inspect the brake pads/rotors.

Since you will be disconnecting the rear brakes lines and will need to purge, consider replacing the fluid with new fluid...might as well purge the front wheels as well. Just a thought, unless the brake fluid has been serviced regularly. Is it 50-75k service life, something like that?

Edit: typos

 

[salisburyv]

I believe the u bolts need to be replace. U joints probably a good idea too.

New fluid on the new differential. Inspect the brake pads/rotors.

Since you will be disconnecting the rear brakes lines and will need to purge, consider rgplacong the fluid with new fluid...might as well purge the front wheels as well. Hust a thought, unless the brake fluid has been serviced regularly. Is it 50-75k service life, something like that?

ok. awesome!! I thought I should do the u joints. it's due for an oil and filter change. Brake fluid change is also I great idea!

 

[West 1]

Brake fluid should be changed every 3 years, it absorbs moisture from the air and starts going bad the day you install it. The moisture inside the system messes up your ABS valves and the calipers. All this is very well known in the industry but most cars on the road have brake fluid equal in age to the car. It helps keep repair places busy.

 

[swathdiver]

thanks for all the info guys, I really appreciate it. I found a unit locally for $250 out the door (plus my core). same year, RPO code , 8.5" ring and pinion and ratio (3.08) I'm gonna go pay for it tomorrow, then they'll pull it for me and I can get it. I tried to use the truck this morning, but it started banging pretty hard and I didn't want to get stuck on the road, and miss work, so I limped her home and took the wife's car. I'm so relived that it's local and I won't have to pay for freight. Donor only has 100k on it, so it should be nice and quiet again. I'll change the fluid and pop the cover off before I install it. Anything I should be telling the salvage guy to leave on there? I'm assuming they're just gonna cut it outta there. I need to see what the interior color is, might ask for some interior bits I want as well. I'll post up when it's road worthy again. thanks again!!

ok. I paid for the unit. They are gonna try to get it to me before Christmas, but he said def by the 26th. Do you guys have any tips/tricks I need to know? what else should I replace while I'm doing this? U joints? Bushings? any info would be helpful. Thanks in advance

Make sure they didn't bend or break any of the brackets or the anchor blocks that the parking brake cables secure to. If you have an impact and a 25mm socket, put it on the yoke nut and spin the axle and listen for any abnormal noises before they leave if possible. Don't give up your core if you need those parts to fix the one they brought you.

Once the truck is up on jack stands, put the axle on the floor jack to maneuver it into position saving yourself from possible injury.

I bought new universal joints for mine but it didn't need them, they're still sitting on the shelf at 220K miles.

Definitely change the fluid. 10-4016 or 88900401 for 2.15 quarts.

The 8.6" factory gasket is reusable. But don't assume the donor has one!

The sway bar bushings are probably due for replacement, they shrink as they age. New axle will probably have old ones still attached. Watch out for those 10mm bolts, they are same diameter as the head and break easily if rusted. PB Blaster!

Inspect the upper and lower control arm bushings and the track bar's (panhard rod) bushings as well.

Even if worn, you can change them later on.

Universal joints are AAM 1355s. You can use Spicer 1350s if they come with different colored clips (snap rings) to get the fit correct.

11mm socket or wrench for the universal joint bolts.

Alright, gotta run, have a funeral to attend.

 

[salisburyv]

Make sure they didn't bend or break any of the brackets or the anchor blocks that the parking brake cables secure to. If you have an impact and a 25mm socket, put it on the yoke nut and spin the axle and listen for any abnormal noises before they leave if possible. Don't give up your core if you need those parts to fix the one they brought you.

Once the truck is up on jack stands, put the axle on the floor jack to maneuver it into position saving yourself from possible injury.

I bought new universal joints for mine but it didn't need them, they're still sitting on the shelf at 220K miles.

Definitely change the fluid. 10-4016 or 88900401 for 2.15 quarts.

The 8.6" factory gasket is reusable. But don't assume the donor has one!

The sway bar bushings are probably due for replacement, they shrink as they age. New axle will probably have old ones still attached. Watch out for those 10mm bolts, they are same diameter as the head and break easily if rusted. PB Blaster!

Inspect the upper and lower control arm bushings and the track bar's (panhard rod) bushings as well.

Even if worn, you can change them later on.

View attachment 474291

Universal joints are AAM 1355s. You can use Spicer 1350s if they come with different colored clips (snap rings) to get the fit correct.

11mm socket or wrench for the universal joint bolts.

View attachment 474292

Alright, gotta run, have a funeral to attend.

Wow!! Thank you for this. what a time saver. I have access to a lift. so I'll remove most of the bolts, then lower it down to get the rest. I'll have my floor jack support it in position until I get it free. inspect and swap over what needs to be swapped. I plan on popping the cover off the "new" one to take a peek before I go through all the trouble of swapping stuff over. I don't expect to do it in 1 day, I tend to be realistic. like I mentioned, on my old Pontiac I swapped the rear end out 4 times. Not because I wanted to either. they weren't built to handle the 400 ish HP they were seeing. Did it in the garage on my back with jack stands and a floor jack.i was also 20 years younger then.... So having a heated garage with plenty of lighting and a heater? should a little easier. but not easy on the whole. I'm gonna pick up 2 u joints and new straps and bolts. also a big jug of brake fluid and the new sway bar bushings. Then go from there.

 

[West 1]

I changed rear axles in my 02 Tahoe twice. It is not a big deal. I did it in my garage, jack stands and a floor jack, I don't remember it taking more than a couple hours and I was 60 at the time. It will go easy for you. Edit: I am on the west coast so had zero rust on any of the bolts. If in part of the country with rusted bolts from salted roads I wish you the best. Some of those are real buggers to repair. Each bolt can cost a ton of time.

I just repaired my daughter in law's Audi, it came from Ohio. One bolt cost me 4-5 hours. Ended up snapping it off, drilling it out, re tapping the hole and installing new bolt. Not fun and should have been a 1 minute job. Salted roads suck.

 

[Marky Dissod]

Even if someone else has already said it, it bears repeating:
Especially if it's salty/rusty, wear eye protection, gottdamnt.
Removing salty rust from your eye carefully cannot be done slowly.

 

[swathdiver]

Wow!! Thank you for this. what a time saver. I have access to a lift. so I'll remove most of the bolts, then lower it down to get the rest. I'll have my floor jack support it in position until I get it free. inspect and swap over what needs to be swapped. I plan on popping the cover off the "new" one to take a peek before I go through all the trouble of swapping stuff over. I don't expect to do it in 1 day, I tend to be realistic. like I mentioned, on my old Pontiac I swapped the rear end out 4 times. Not because I wanted to either. they weren't built to handle the 400 ish HP they were seeing. Did it in the garage on my back with jack stands and a floor jack.i was also 20 years younger then.... So having a heated garage with plenty of lighting and a heater? should a little easier. but not easy on the whole. I'm gonna pick up 2 u joints and new straps and bolts. also a big jug of brake fluid and the new sway bar bushings. Then go from there.

Before ordering any parts from my list, verify the part numbers against your application. I know the short Yukons use different control arms than the longer ones for example.

 

[West 1]

For loosening old salty stuck bolts many advise Kroil or PB Blaster but the most effective product is a 50/50 mix of tranny oil/ ATF and acetone. Soak the bolts for a day before the job makes life easier.

 

[salisburyv]

For loosening old salty stuck bolts many advise Kroil or PB Blaster but the most effective product is a 50/50 mix of tranny oil/ ATF and acetone. Soak the bolts for a day before the job makes life easier.

I greatly use PB as well. I'll look into getting the acetone. it's really rusty under that truck. lived it whole life on the coast in New England so.....

I did double check before I pulled the trigger on the u joints. I got them, new straps and U bolts. I'll go local for the brake fluid. just talked to my bro in law to prepare him for the festivities, lol. He said it should be fun. Yeah, providing it's not too cold, the diesel heater they have makes me sick when I'm around it. oh well.

 

[swathdiver]

I greatly use PB as well. I'll look into getting the acetone. it's really rusty under that truck. lived it whole life on the coast in New England so.....

I did double check before I pulled the trigger on the u joints. I got them, new straps and U bolts. I'll go local for the brake fluid. just talked to my bro in law to prepare him for the festivities, lol. He said it should be fun. Yeah, providing it's not too cold, the diesel heater they have makes me sick when I'm around it. oh well.

Put plenty of oil in the preceding days on those brake bleeders on the calipers! Maybe have a spare or two since you live in the land of road salt.

 

[salisburyv]

Update: we had first snow of the season. about 6". so I didn't start as early as I had wanted to. old ones out/new one is in. The brakes on the new one look almost new, so I be keeping them. starting wrapping things up, it was a PITA to get the upper trailing arms lined up, but with the help of the floor jack we got em. 75w90 gear oil doesn't really want to flow at 10 degrees. so at 9pm this evening I called it. gonna wait till Tuesday to finish up. its going to be 50 degrees so I'll be able to fill the new diff. the fluid in the new diff looked new, no darkness at all and I could see through it. Don't know if I should be happy, or wary. But the gears look pristine, like I said the brakes look newish. I possibly got this from a very well maintained vehicle? fingers crossed. that assembly is HEAVY. 1 casualty. my father in laws $500 70000 btu diesel heater. it was too close to the vehicle when he dropped the lift down, but he bitched to my wife it was my fault. said nothing to me tho..... that's all for now. I'll report back when I confirm all is well.

 

[West 1]

Progress, rather than fight the thick oil bring inside overnight. Warm oil flows fine.

 

[salisburyv]

Progress, rather than fight the thick oil bring inside overnight. Warm oil flows fine.

So does temps in the 50s.... got it all wrapped up and drove it. its much better way harder than I thought it would be

 

[West 1]

Success, you will forget how long it took as the miles with no problems pile up.