Worn or crack teeth in the metal.

 

Hey, thanks for the answer. Not sure what you mean though, you see excessive wear in photos or you mean this is what I should be looking for? I don't see any cracks, bruises. The surface is flat and smooth, shiny. I can't really feel any difference in height between the shiny part and the black piece of tooth. So can I assume that's normal? Or maybe it should all be black? Sorry for the lame questions, it's my first opened diff ever.
Also, what's the standard ratio on 8.25 front diff? 3,73?
And what gear brand would you recommend, potentially? Something cheap but good quality.

 

Hey, thanks for the answer. Not sure what you mean though, you see excessive wear in photos or you mean this is what I should be looking for? I don't see any cracks, bruises. The surface is flat and smooth, shiny. I can't really feel any difference in height between the shiny part and the black piece of tooth. So can I assume that's normal? Or maybe it should all be black? Sorry for the lame questions, it's my first opened diff ever.
Also, what's the standard ratio on 8.25 front diff? 3,73?
And what gear brand would you recommend, potentially? Something cheap but good quality.

I did not notice the tiny pic link. Going by the picture the gears looks good if it looks the same all around without any cracks or chipped metal.

I would go with a brand like Yukon Gear for gear sets based on their reputation. The Cadillac has the front differential with the IFS 8.25 with a stock 3.73 gear ratio.
Never use cheap quality parts.

Cadillac Escalade GM 8.25" IFS Front, '99-'09 categories

 

AWD escalades had the 3.73 ratio, front and rear.

I see you are outside of the US, so parts availability may be limited. But I wouldn't cheap out on a driveline critical part if at all possible. Either go with OEM, or OEM+, meaning the same brand that came with the vehicle, or something that's better/stronger.

 

Your diff. Looks ok to me. As long as you don’t have any broken or chipped teeth you are good. The discoloration you see is an indication that the teeth are fully meshing which is what you want verses only the tips meshing. It spreads the load over the entire tooth as opposed to just the tips.

 

Sorry for delay in responses, i was coming back from vacation. I guess I'll just replace bearings for now. The store I usually buy parts from has Yukons, USA STANDARD GEAR (which I understand is lower quality Yukon sub-brand), Richmond and ACDelco. Between Richmond and Yukon, which one would you recommend?

Two more questions:
1. When installing a pinion and setting a pre-load on bearings there is this torque wrench with memory dial to spin the pinion and see how much force it requires. It costs like $200 and I would like to avoid spending that much on a tool I'll probably use once. Any tips on how to test the pre-load in some cheaper way?
2. (Since I will reuse the existing ring and pinion, I hope I won't be needing this information as the shim is already there, but for future reference). As far as I can see, you need to adjust initial pinion depth for each new set of teeth by putting a shim of the right thickness between the pinion and the bearing. For rear diff, there is a gauge that you install in the holes where half-axles go and you can measure the depth. But you need to split the front in half to disassemble it, so how do you determine which shim should be used? I am not talking about the backlash adjustment (so ring/pinion play), but about setting the teeth to properly mesh together. Any other way than putting in the shim & bearing, painting gears, check pattern and remove the bearing again to use another shim?

 

I have never done a differential rebuild, however from what I researched you got it down so far. You could try buying a very cheap memory dial tool since it would be a single use item, but I would just buy a decent quality tool so that the job is done right the first time. I would go with Yukon Gear due to it being a brand I am familiar with. AC/Delco would be good as well since the stock stuff last a long time.

Here is one for $150 on amazon

 

Yes, well, that's the $200 tool I was actually talking about, when you count in the shipping and EU taxes
EDIT: And any advice between Richmond and Yukon? ACDelco is 2x the price...

 

Buy it and get the job done.

 

Ok, one last question before I order new parts. Anything else I should do as a good practice since front diff is out? I am replacing oil cooler lines since they have never been replaced and are sweating, but anything else?

 

I would tackle the transmission cooler lines since the front diff is out of the way. I recently changed my transmission cooler lines and it was a pain to changed them with the front diff in place. Possible, but much harder trust me.

 

Heh, I know, already did them before I pulled the diff since they were pretty rusted. For me the trickiest part was to insert back the retainer clip on the transmission, took me quite a while and I lost one. In case anyone else needs it, in EU Opel also sells this clip for Opel Signum, part number 753363 (GM 24205103) 😆
Parts ordered, so let's see how this goes.

 

Man, those clips are pain to get to on the transmission. I used long handled pick tools to remove them fairly easy, however it was very hard for me to reinstall the clips correctly as well. Took a while to get it right.

Good luck, I am sure it will go well. You seem to have done your research to do it correctly.

 

Oil pan gasket is pretty accessible after the differential is out of the way.

 

Did you replace the wheel bearings on all the wheels or just the front or back.

 

Hey after some time. I finished the diff, works fine it seems, the oscillating noise when coasting/slowing down is gone. So that's good.
@tokuzumi You are right, but I changed oil in the spring and it isn't leaking. Also, I'll probably wait a year with this to drive the car some and do it along with pulling the tranny and changing rear main seal.
@Cameron0588 just the fronts, I was trying to get rid of the noise. Probably a little too early, since the source of noise turned out to be differential bearing. But it was easier than playing the guessing game with all the front bearings, and also one ABS cable was pinched & wet which was giving me the "traction active" issue.