Build thread - 3.08 to 3.42 front and rear gear change

[DaveO9]

They ought to be thoroughly inspected. I would also rotate the pinion with the carrier removed to check for binding from any corrosion it may or may not have.

Mine got rained on after we put the new yoke in the 2nd time and got the crush washer in and rotational torque to where it's supposed to be. We drained out the rainwater and poured 2 quarts of gear oil into the case and let it sit for a few days. All seems well.

So is removing the carrier a simple unbolt/bolt back in operation? All the shimming is done with pinion? I’ve never done anything with a diff before.

There was no oil in the case when I got it, whereas first one from LKQ was full. I was thinking that part of diff just dried out over time and then got surface rust from moisture in the air. Since there’s a vent, the air eventually equalizes humidity with atmosphere. Everything else I can see and feel in the case still has a good coating of oil.

 

[swathdiver]

So is removing the carrier a simple unbolt/bolt back in operation? All the shimming is done with pinion? I’ve never done anything with a diff before.

There was no oil in the case when I got it, whereas first one from LKQ was full. I was thinking that part of diff just dried out over time and then got surface rust from moisture in the air. Since there’s a vent, the air eventually equalizes humidity with atmosphere. Everything else I can see and feel in the case still has a good coating of oil.

I don't know for sure. I figure yours was stored upside down and all the fluid leaked out the vent. This happened to one of mine on the way home from LKQ once.

If yours was mine, I would measure the backlash first and maybe do a contact pattern on the gear teeth and then note the position of the adjuster on the right side and the cast iron shim on the right and pull the caps and then the carrier to inspect the bearings. Since nothing was changed, it all ought to go back together with the same clearances. If you change the bearings, it still should go back together with the same clearances to my way of thinking. But like you, I am not formally trained in this. Who here was?

 

[j91z28d1]

is it not shims on both side bearings in the diff?

I have done some Ford 9in center section that had adjustment, but I didn't know gm every did it.

 

[DaveO9]

I don't know for sure. I figure yours was stored upside down and all the fluid leaked out the vent. This happened to one of mine on the way home from LKQ once.

If yours was mine, I would measure the backlash first and maybe do a contact pattern on the gear teeth and then note the position of the adjuster on the right side and the cast iron shim on the right and pull the caps and then the carrier to inspect the bearings. Since nothing was changed, it all ought to go back together with the same clearances. If you change the bearings, it still should go back together with the same clearances to my way of thinking. But like you, I am not formally trained in this. Who here was?

Ah yes, maybe that's how the oil was drained. I was wondering about that since it seems like the gasket was original or at least hadn't been disturbed for a long time.

In any case, I looked at it much more closely tonight, but without removing the main caps. And I've decided I'm going to take a calculated risk and not pull the carrier at this time. I'm worried I could do more harm than good, and this project has ballooned in cost and time. I could see the rollers on both bearings (had to use a mirror to see the left side) and they are all coated in oil. I listened and felt carefully in making a full rotation and did not hear or feel any rough spots. I know the most prudent thing to do would be to pull the carrier and fully inspect all the bearings, and I do appreciate the input, but I feel like it's a low risk decision looking at everything else inside there. I'm an engineer that works on the asset management side of the house for a large electric utility - pretty common for us to have to make these types of decisions, but on a much large scale of course.

is it not shims on both side bearings in the diff?

I have done some Ford 9in center section that had adjustment, but I didn't know gm every did it.

There's a single adjustment mechanism on the right side.

On a different note, I picked up my 3.42 front today and (sigh of relief) it looks identical in every way to the 3.08 I pulled out. Also my Denso radiator was delivered today, several days early. And my single motor mount arrived a few days ago and have started, but not finished, getting the DS mount out. Will be a long weekend, hoping to get everything put back together by Sunday night, but we will see. Things have a way of not going as planned.

 

[swathdiver]

Ah yes, maybe that's how the oil was drained. I was wondering about that since it seems like the gasket was original or at least hadn't been disturbed for a long time.

In any case, I looked at it much more closely tonight, but without removing the main caps. And I've decided I'm going to take a calculated risk and not pull the carrier at this time. I'm worried I could do more harm than good, and this project has ballooned in cost and time. I could see the rollers on both bearings (had to use a mirror to see the left side) and they are all coated in oil. I listened and felt carefully in making a full rotation and did not hear or feel any rough spots. I know the most prudent thing to do would be to pull the carrier and fully inspect all the bearings, and I do appreciate the input, but I feel like it's a low risk decision looking at everything else inside there. I'm an engineer that works on the asset management side of the house for a large electric utility - pretty common for us to have to make these types of decisions, but on a much large scale of course.


There's a single adjustment mechanism on the right side.

On a different note, I picked up my 3.42 front today and (sigh of relief) it looks identical in every way to the 3.08 I pulled out. Also my Denso radiator was delivered today, several days early. And my single motor mount arrived a few days ago and have started, but not finished, getting the DS mount out. Will be a long weekend, hoping to get everything put back together by Sunday night, but we will see. Things have a way of not going as planned.

Sounds good. Got my carrier dropped in today and was at .003 backlash but did not have the special spanner to tighten the adjuster on the side. The brass drift I was using was bending. So I quit being a cheapskate and bought the $184 spanner. We were melting in the garage at 0730 anyway, too hot to work outside today for me.

 

[DaveO9]

Sounds good. Got my carrier dropped in today and was at .003 backlash but did not have the special spanner to tighten the adjuster on the side. The brass drift I was using was bending. So I quit being a cheapskate and bought the $184 spanner. We were melting in the garage at 0730 anyway, too hot to work outside today for me.

Awesome. Hot here this weekend, too, but probably not as hot. Worst time for me is late afternoon - sun dips down and shines into my west facing OH shop door. And I was working on the back of the rig this weekend.....

Got the rear end installed, all went in pretty easily. I'm to the point of mounting the rear wheels and install driveshaft and I'm done in back. Front, not so much. Finally got the old motor mount out today and the new one dropped into place with all but one bolt threaded in finger tight. I've had the most trouble with the front upper engine-to-mount bolt, both coming out and going in. I'll probably just have to bend the heat shield like I did to remove the old mount. After the mount is done, still have to
- remove and replace radiator/hoses
- run new Dorman oil cooler lines to new Denso radiator (new radiator has engine oil cooler, old one doesn't)
- Change oil and filter
- Install front carrier assembly
- change oil in front diff
- front driveshaft and axles
- hook everything up, etc. etc.

@swathdiver or anyone else: do you know where this hanger goes? Pretty sure it came from the passenger side, but it's not showing up in any of my before pics. There's a similar longer one on the pass side for parking brake cable, so I think that's what it is, but I can't find where it goes. It seems like the p-brake cable is already pretty well supported without it.

 

[swathdiver]

@swathdiver or anyone else: do you know where this hanger goes?

View attachment 435082

That one goes on the driver's side lower control arm bracket on the axle. It faces the differential housing. You'll see the threaded hole for it.

 

[5StarCustmSolutns]

Q: Dumb question: could you do a hummer mount on DS and stick with Tahoe OEM on Pass side? I'm not going to do this now, but something I've been thinking about if I DO have a failure on DS some day, or if I do some motor upgrades.

A: Yes, no problem. This is how my 2012 is currently.



More like a little high quality Q & A there!

 

[5StarCustmSolutns]

edit: Disregard this post.... In my drearyness, I somehow skipped everything below my post on page 4..... and no there were no spiral notebook lines indented into my face


I just woke up face down on my bench about 15min ago. So I apologize if I missed this but: Curious what the fluid looked like inside your 14 with 82k on it??

Mine had 92k on clock and it looked like golden caramel lol. Had to have just performed their 100k service before letting a mild accident retire a beautiful Denali XL....smh
Just made me think, I hit......correction: A deer hit me a couple years ago and my Ins. adjuster was suggesting I'd come out ahead if I just totaled it . Literally suggesting I total loss claim my truck from a 100lb fawn helicoptering from front tire to back.... No wonder premiums climbing everywhere

 

[5StarCustmSolutns]

is it not shims on both side bearings in the diff?

I have done some Ford 9in center section that had adjustment, but I didn't know gm every did it.

No sir. Not in the 14.

It has a threaded dial on the right hand side that looks like a vertically aligned preload dial on a coilover. Has the exact same function, only transversely pressing from the passenger side. It's the only one I've ever done, but it was much easier than the shim style setups lol...

 

[5StarCustmSolutns]

Awesome. Hot here this weekend, too, but probably not as hot. Worst time for me is late afternoon - sun dips down and shines into my west facing OH shop door. And I was working on the back of the rig this weekend.....

Got the rear end installed, all went in pretty easily. I'm to the point of mounting the rear wheels and install driveshaft and I'm done in back. Front, not so much. Finally got the old motor mount out today and the new one dropped into place with all but one bolt threaded in finger tight. I've had the most trouble with the front upper engine-to-mount bolt, both coming out and going in. I'll probably just have to bend the heat shield like I did to remove the old mount. After the mount is done, still have to
- remove and replace radiator/hoses
- run new Dorman oil cooler lines to new Denso radiator (new radiator has engine oil cooler, old one doesn't)
- Change oil and filter
- Install front carrier assembly
- change oil in front diff
- front driveshaft and axles
- hook everything up, etc. etc. View attachment 435081

@swathdiver or anyone else: do you know where this hanger goes? Pretty sure it came from the passenger side, but it's not showing up in any of my before pics. There's a similar longer one on the pass side for parking brake cable, so I think that's what it is, but I can't find where it goes.

what (@swathdiver) he said...

It goes under driver side bump stop plate on the inside of the frame rail. You kind of have to get down and dirty there to see it as it threads in on the underside. It steers the brake cable onward and upward immediately after clearing axle tube, on its climb up to it's next point of contact along upper control arm.....

 

[mikez71]

Q: Dumb question: could you do a hummer mount on DS and stick with Tahoe OEM on Pass side? I'm not going to do this now, but something I've been thinking about if I DO have a failure on DS some day, or if I do some motor upgrades.

A: Yes, no problem. This is how my 2012 is currently.

More like a little high quality Q & A there!

Honestly that maybe optimum!

When I had only the driver side H3 mount and stock passenger mount, I hadn't yet noticed any increase in vibration.
After installing the passenger side, I was certainly feeling more vibration.

I know everyone wants to replace parts as a balanced set (I do), but I think installing just driverside H3 mount will still reduce the torquing movement,
which should reduce the peak force that the weaker mount experiences due to less slack/movement.
Kind of like an engine torque strap chain, usually just installed on the lifting side?

So *I* think, a mixed set with one H3 mount, should outlast matched OEM liquid filled mounts.

BACK to AXN axle info.. Would I be good to order from LKQ online? I see one that is from a 2014 111k miles..
Many recyclers around me, but I haven't had great experiences going there..

 

[5StarCustmSolutns]

SON of A GUN! @mikez71 I had three short paragraphs typed to answer you and tried to see where you live for final advise on LKQ vs local and lost it all....lesson learned

Two summers ago I was determined to sell GMT900 and get diesel. Looked at 1000's. Noticed trend: In pic from rear- left side was lower than right. Tail gate slanted down & left on vast majority. Brought it up at local engine builder shop. 5 guys there, 5 diff opinions. Called owner later, around midnight(he go bed at like 8pm lol) and said "I know what it is: Engine torquing on frame" Pretty sure he hung up on me. He called me back next day said I think you may be right? Makes for an interesting conversation, at a minimum

Only experience I have with motor mounts was on 2004 Acura TL. Was in Philly working. About 36yrs old and already knew EVERYTHING(not so) Developed thud on take off. Went to dealer, put on low lift, had me punch it and said it's motor mount. Well I knew it was transmission so I disputed. We traded places. He punched it. Me: WHOA WHOA WHOA! One side of engine jumped about 10" and slammed back down. IDK how it didn't break off? or hit hood? I need to replicate that with my truck now...

AXN: Self Source vs LKQ (or similar) = Time & Patience vs No Time & Money... If you live somewhere with larger car market or don't mind a drive to get one then self source it. I think I was as motivated by the core charge and amount they were selling the 10 bolts for than anything. $300 core charge at time. In essence they were charging me 300 to keep my 10 bolt, yet they were selling for $12-1400.. +$250 shipping... And selling 14 bolts for $5-750. At the time I thought they were taking these cores and slapping G80's in them to make $1000 each. I was looking at $800-1000 range to get a 14 and then shipping them my 10 bolt... Now I know that was giving them wayyyy too much credit. I don't think they don't get off the stool except for bathroom trips....or.....they certainly will not get off the stool and walk to the axle you're wanting to confirm it a 14 9.5... What computer says is what it is! Until you drive there and it's not.....twice

Self source wasn't easy but I learned a lot and scored a 14 bolt for $212 w/NO core charge, 3hrs away in Winston-Salem NC. Affording me the opportunity to put a $350 Yukon Posi or a $100 used G80 carrier in my old 10 and sell it for >$1000....or keep as backup? or use it for lawn furniture(current choice).....its shrink wrapped behind my garage
If you self source or anyone that reads this, I will, as long as I have cognitive ability, read back through my threads and convos with members to help you decipher the VIN yourself....so you don't have to try and get a junkyard dog off his stool

 

[DaveO9]

That one goes on the driver's side lower control arm bracket on the axle. It faces the differential housing. You'll see the threaded hole for it.

Got it, thanks. Hanger bracket for both p-brake cables installed now and functional in the bracket for the LCA!

I just woke up face down on my bench about 15min ago. So I apologize if I missed this but: Curious what the fluid looked like inside your 14 with 82k on it??

All the oil had drained out of mine when I got it from LKQ, so I don't know.

Speaking of rear diff lube, mine's leaking. I used this gasket:

More Information for GM GENUINE 26063649

That shouldn't need RTV on either/both sides, correct? Goes on dry? I'm not sure why it's leaking. Best guess: When I was jacking the axle into place, the jack plate caught on the lip of the cover. I thought the tweak was just superficial, but now I'm wondering if it tweaked it just enough to make a poor seal between those two bolt holes. Remove and gently hammer flat? Can I reuse the gasket? What about just using RTV (Permatex Black) instead of or with the gasket?

In other news - DS motor mount is fully installed with all 7 bolts torqued down. Very pleased to have that part of the project done.

 

[DaveO9]

BACK to AXN axle info.. Would I be good to order from LKQ online? I see one that is from a 2014 111k miles..
Many recyclers around me, but I haven't had great experiences going there..

Yes, I'd say go for it with LKQ Online. More info in my post #20 of this thread, but the big benefit with LKQ Online, at least for axles and carriers, is no core charge. So if you're upgrading to AXN, that's a big plus. When I tried to order from LKQ Portland, OR (20 miles from me) they quoted me a slightly cheaper price than online, but there was close to a $200 core charge. The other thing with LKQ online is find what you're looking for on the website, but then call the number during work hours to order. If you order online, you'll have to have it shipped to an address, which for me was $300 plus. But if you call, they'll transfer it to the LKQ will call closest to you for $50. I don't know if there's distance limit, but mine came from Idaho and CA - hundreds of miles away. Customer service on the phone is very good. You may have to wait for 15 minutes, but once you get someone they'll work with you till you're set up.

 

[swathdiver]

Got it, thanks. Hanger bracket for both p-brake cables installed now and functional in the bracket for the LCA!



All the oil had drained out of mine when I got it from LKQ, so I don't know.

Speaking of rear diff lube, mine's leaking. I used this gasket:

More Information for GM GENUINE 26063649

That shouldn't need RTV on either/both sides, correct? Goes on dry? I'm not sure why it's leaking. Best guess: When I was jacking the axle into place, the jack plate caught on the lip of the cover. I thought the tweak was just superficial, but now I'm wondering if it tweaked it just enough to make a poor seal between those two bolt holes. Remove and gently hammer flat? Can I reuse the gasket? What about just using RTV (Permatex Black) instead of or with the gasket?

View attachment 435151

In other news - DS motor mount is fully installed with all 7 bolts torqued down. Very pleased to have that part of the project done.

I've always used orange RTV on both sides, very thin, on paper gaskets like this. I ordered a Lube Locker off of Amazon, should be here in a few days. It's supposed to be reusable. My daughter came by and raided my spares!

Too bad nobody makes the rubber/metal one like the 10-bolts. Mine is still rockin' the original one.

 

[5StarCustmSolutns]

That shouldn't need RTV on either/both sides, correct? Goes on dry? I'm not sure why it's leaking. Best guess: When I was jacking the axle into place, the jack plate caught on the lip of the cover. I thought the tweak was just superficial, but now I'm wondering if it tweaked it just enough to make a poor seal between those two bolt holes. Remove and gently hammer flat? Can I reuse the gasket? What about just using RTV (Permatex Black) instead of or with the gasket?

I've always used orange RTV on both sides, very thin, on paper gaskets like this. I ordered a Lube Locker off of Amazon, should be here in a few days. It's supposed to be reusable. My daughter came by and raided my spares!

Too bad nobody makes the rubber/metal one like the 10-bolts. Mine is still rockin' the original one.

Originally cheaped it, bought an $8 paper gasket. Looked at it for a couple weeks. Picked it up a couple times. Dropped it once, and gasped because I thought it was going to be damaged. Even made a protective case, a giant envelope of cardboard and painters tape to protect it.....then one day I thought this is way too big of a project to not go all the way! And ordered the $30 Lube Locker!
Where I once worried about creasing or fraying the fibers of the frail paper gasket.....We were now using the Lube Locker as a frisbee during lunch and as a pillow for mid day siesta's! ;-)

 

[DaveO9]

@swathdiver or @5StarCustmSolutns: could either of you send me an Amazon link for the lube locker gasket? I am not finding it there or on RA. Thanks!

 

[5StarCustmSolutns]

@swathdiver or @5StarCustmSolutns: could either of you send me an Amazon link for the lube locker gasket? I am not finding it there or on RA. Thanks!

Got mine from Summit, but could've been in big order and free shipping?

Pardon Our Interruption

Quick Perf shows free ship to WV in case Summit hitting over the head for ship??

LLR-G14SF-GM 9.5" / 14 Bolt Semi-Float / LubeLocker / P

www.quickperformance.com

edit: Did not see on Amazon, went through all 7 pages of LL gaskets

 

[DaveO9]

Got mine from Summit, but could've been in big order and free shipping?

Pardon Our Interruption

Quick Perf shows free ship to WV in case Summit hitting over the head for ship??

LLR-G14SF-GM 9.5" / 14 Bolt Semi-Float / LubeLocker / P

www.quickperformance.com

edit: Did not see on Amazon, went through all 7 pages of LL gaskets

thanks, on order from quickperf!