No rear Diff Drain Plug on my "08" LS

jbones

Original poster
Member
Dec 5, 2011
658
What the ..... I got no rear drain plug. I never thought to look first, fill plug yes, but no drain. Was going by the Haynes, and service manual of which both show a drain plug. So I guess changing my fluid change requires the removal of the read axel cover, and as luck would have it today is New Years Day, nothing open and I have no gasket. I guess no rear servicing today!


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Dec 4, 2011
518
You are correct the diff cover needs to be removed. The good news is that there is a rubber gasket between the cover and the case and it is meant to be reused. Just be a little careful removing it so you don't destroy it.

Good luck should only be a 1/2 hour job. Just remember to take the fill plug out first so you can be sure to be able to refill. In addition if you get a bottle pump (a couple of bucks) that will screw to the refill bottle it will be a snap to refill. More thoughts, be sure to use a good synthetic (Amsoil, Royal Purple, Mobil 1) refill fluid.
 

The_Roadie

Lifetime VIP Donor
Member
Nov 19, 2011
9,957
Portland, OR
The Haynes manual was written around a 2002-2003 vehicle before GM took out the drain plug to save a dime. Besides, if you remove the cover, you have access to the magnet so you can clean that off of magnetic particles (worn off gear surfaces) and make sure it's all tiny particles and nothing larger has broken off.

I agree it's critical to make sure you can remove the fill plug before pulling the cover. Put it back in with some anti-seize to make the next time easier.

Edit: CRITICAL WARNING. The cover bolts were put in at the factory with loctite. Be very careful removing them, and you might need to do the "back out 1/2 turn, put back IN 1/4 turn" trick to get them out safety. The reinstalling torque spec is tiny - 20 ft-pounds. Use the removable loctite to put them back in. The fill plug also needs very little torque - 24 ft-pounds. It's above the fluid level, so there's no critical need for it to be totally seep-free.
 

jbones

Original poster
Member
Dec 5, 2011
658
RedEnvoyDenal said:
You are correct the diff cover needs to be removed. The good news is that there is a rubber gasket between the cover and the case and it is meant to be reused. Just be a little careful removing it so you don't destroy it.

Good luck should only be a 1/2 hour job. Just remember to take the fill plug out first so you can be sure to be able to refill. In addition if you get a bottle pump (a couple of bucks) that will screw to the refill bottle it will be a snap to refill. More thoughts, be sure to use a good synthetic (Amsoil, Royal Purple, Mobil 1) refill fluid.

Same gasket, that good news, will be careful thanks. Lost my time frame now, getting ready to head off to the kids for dinner. Got all the stuff needed , did the front a few week back. I have Valoline Synthetic for the rear, used the Mobil in the front.

After I couldn't complete I moved on to the Throttle Body, It didn't look to bad so I left it on and buttoned things back up. I figure I wouldn't fix what's no broken, truck is running fine anyway.


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woody79

Member
Dec 3, 2011
351
This is all good stuff to know. I have '08 and was planning on changing out the rear diff fluid soon. At least I won't be surprised when I find no drain plug now :crazy:
 

ScarabEpic22

Member
Nov 20, 2011
728
Jeff, I would have cleaned the TB as long as you had it that far apart. I can tell by that pic that the backside of the blade is going to be caked with gunk, the front always looks clean but the back will be bad.

And yep on the drain plug, my 02 has one but I know other years arent as lucky.

Good meeting you yesterday!
 

jbones

Original poster
Member
Dec 5, 2011
658
the roadie said:
SNIP...GM took out the drain plug to save a dime.

And GM still needed a bailout:confused:

Thanks for the tips on the bolts, and magnet. Will be sure to remove fill first. The factory didn't use permanent like red loctite did they? I do have blue loctite and anti-seize. I just can't find my torque wrench right now, but then I haven't seen it since I moved from San Diego.
 

MichEnvoyGuy

Member
Dec 3, 2011
522
ScarabEpic22 said:
I can tell by that pic that the backside of the blade is going to be caked with gunk, the front always looks clean but the back will be bad.

:iagree:

The backside is what gets gunked up and by the looks of it - yours has some buildup for sure. The front side lies.
 

jbones

Original poster
Member
Dec 5, 2011
658
ScarabEpic22 said:
Jeff, I would have cleaned the TB as long as you had it that far apart. I can tell by that pic that the backside of the blade is going to be caked with gunk, the front always looks clean but the back will be bad.

And yep on the drain plug, my 02 has one but I know other years arent as lucky.

Good meeting you yesterday!

Well shoot, dirty on the back side you say! I guess I'll just have to break it down again tomorow, after all I bought the TB cleaner and rags yesterday, and no sense in returning the items; well maybe to my wife there is:smile: Was good meeting you also.
 

The_Roadie

Lifetime VIP Donor
Member
Nov 19, 2011
9,957
Portland, OR
ScarabEpic22 said:
... the backside of the blade is going to be caked with gunk, the front always looks clean but the back will be bad....
I had a series of analogies going on the OS about what the backside of a dirty throttle body looked like.

"...as dirty as the inside of an original 1880 Dodge City saloon spittoon." and so forth.
 

jbones

Original poster
Member
Dec 5, 2011
658
Well now you guys weren't kidding, the back side was nasty:redface:. I'll try to get back the reason of the thread tomorrow and knock out the rear diff.

Thanks for sending me back in.

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woody79

Member
Dec 3, 2011
351
jbones ... you'll have to let me/us know how you make out doing the rear diff. Pics would be great also :smile: Its on my to-do list as soon as I get some jack stands.
 

ieatglue

Member
Nov 20, 2011
152
I think that is the shiniest throttle body I have ever seen!! :eek:
 

Wyle

Member
Dec 4, 2011
200
the roadie said:
Edit: CRITICAL WARNING. The cover bolts were put in at the factory with loctite. Be very careful removing them, and you might need to do the "back out 1/2 turn, put back IN 1/4 turn" trick to get them out safety. The reinstalling torque spec is tiny - 20 ft-pounds. Use the removable loctite to put them back in. The fill plug also needs very little torque - 24 ft-pounds. It's above the fluid level, so there's no critical need for it to be totally seep-free.

Good info, Roadie. I noticed the loctite when I changed fluid and wondered if/why someone had been in there during the first 14k miles before I owned it. Nice to know it was "factory fresh". Cleaned the bolts but not the holes when I put it back on without loctite. I'll probably pull one at a time and add it next time I'm under there.
 

Mooseman

Moderator
Dec 4, 2011
25,257
Ottawa, ON
the roadie said:
The Haynes manual was written around a 2002-2003 vehicle before GM took out the drain plug to save a dime. Besides, if you remove the cover, you have access to the magnet so you can clean that off of magnetic particles (worn off gear surfaces) and make sure it's all tiny particles and nothing larger has broken off.

Not to diss the all knowing Roadie, there was a magnet in the drain plug of my '02 and none on the cover.
 

jbones

Original poster
Member
Dec 5, 2011
658
Sorry, I didn't get around to the rear diff today, just feeling pooped today. And on the fourth day I rested. New Years 4-day weekend coming to a close, and back to work tomorrow, and, there's Gun Smoke Marathon on TV today. I have all kinds of excuses for not getting off the couch today.

I guess next weekend will have to do.
 
Jan 21, 2012
58
I changed the rear diff cover to a PML Inc aluminum cover it comes with a fill hole and a drain with a magnetic plug Note needed to grind down one of the cooling fins to clear the track bar. I also use quaker state 75/140 syntetic. pull our 26 ft trailer a lot.
 

jbones

Original poster
Member
Dec 5, 2011
658
Enderbygrandpa said:
I changed the rear diff cover to a PML Inc aluminum cover it comes with a fill hole and a drain with a magnetic plug Note needed to grind down one of the cooling fins to clear the track bar. I also use quaker state 75/140 syntetic. pull our 26 ft trailer a lot.

How about crawling back underneath taking a PIC, and posting the PIC of that nice mod installed. :smile:
 

woody79

Member
Dec 3, 2011
351
jbones said:
How about crawling back underneath taking a PIC, and posting the PIC of that nice mod installed. :smile:

:iagree:
 

djthumper

Administrator
Nov 20, 2011
14,950
North Las Vegas
jbones said:
Got any 5-yr olds in the area to lend a hand. Just kidding:raspberry:

That isn't too far fetched. My 5 y/o showed my wife how to upload pics to facebook this weekend. He said he learned from watching me. :cool:
 
Jan 21, 2012
58
well I got a picture but its too big and havent figured out how to shrink it yet. keep making fun of me and im agonna have to wack u with my cane lol
the part number for the cover was 11035.
I also took a couple of pictures of my extendable mirrors that i had to modify to fit normally fit 2000 chev pu
 
Jan 21, 2012
58
View attachment 18144
ok I think I have the pictures.
re the mirrors I made an adapter out of a piece of 2x10 fir because the bolt patterns are different and the piece of the mirror that goes against the door is smaller on the pick up mirrors. it was a bit of a B to figure out how to put the two bolt patterns in I also put in a couple of pieces of metal strapping just in case the wood wouldn't hold
but it has been about three years now and still no problems! note I painted them numerous times with enamel paint.
 

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djthumper

Administrator
Nov 20, 2011
14,950
North Las Vegas
Enderbygrandpa said:
I think that the rear diffs for all the I6 are the same but Roadie can probably confirm. or check dealership parts and check if the cover part # changes thru the years.

jbones said:
Because we have the 8.0" Axle?

I am thinking it only lists up to 2005 because 2006 may be when they deleted the drain plug. I guess I will need to take a look. All of the non SS' have the 8" rear end and the XLs should have 8.5".
 

Wooluf1952

Member
Nov 20, 2011
2,663
Milwaukee, Wisconsin
djthumper said:
I am thinking it only lists up to 2005 because 2006 may be when they deleted the drain plug. I guess I will need to take a look. All of the non SS' have the 8" rear end and the XLs should have 8.5".

The drain plug was deleted some time in the 2003 model year.

The 8.5" (8.6"?) was used on LWB and SWB with the 5.3 V8.
 

djthumper

Administrator
Nov 20, 2011
14,950
North Las Vegas
Wooluf1952 said:
The drain plug was deleted some time in the 2003 model year.

The 8.5" (8.6"?) was used on LWB and SWB with the 5.3 V8.

dang, I knew it didn't look right... Time to get some sleep
 

The_Roadie

Lifetime VIP Donor
Member
Nov 19, 2011
9,957
Portland, OR
Enderbygrandpa said:
I think that the rear diffs for all the I6 are the same but Roadie can probably confirm.
The guy we're all indebted to is AlekG from Toronto, who bought two spare covers years ago, one for the 8.0" and one for the 8.6". He confirmed the hole patterns are the same, just the depth was different, then he convinced Purple Cranium company to design and fabricate a Spider differential guard for our platform. As has been posted, the I6 can be found in some LWB vehicles with the 8.6" differential. There are a few SWB I6 that have had axle upgrades for offroading robustness like mine.
 

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