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Discussion Starter · #1 · (Edited)
Hi all!

I just recently had my angle gear fail on my 04 S60R. Just before the summer I took my AG off to reseal it cause it was leaking oil pretty badly. Now when I did that I noticed that not a lot of oil came out of the AG. But the bearings felt okay and also the pinion and ring gear teeth looked normal. I grinded the edge of the cover on the AG as the TJ recommends it. Here's the link: http://www.volvoxc.com/0/resources/...NN, Drivetrain - Angle Gear Fluid Leakage.pdf

Also that time I replaced my collar sleeve. Old one was in a good shape, but I figured that why the hell not since the AG is off anyways. AG resealed and filled up with oil and it was all good. Until last week. It's winter so one might drive a lot sideways and the AG got some beating. Then it started to make this very small grinding noise. I could barely hear it since the IPD Oval catback is quite loud. But lifting up the car verified that the sound was coming from the AG. I reckon that by the time I did the reasealing procedure in the beginning of summer it was already broken. Now with new oil and the correct amount of it, it might've been okay for a while but eventually it was going to fail. I work at a Volvo dealership and a new AG for me would've cost around 1200EUR. It is cheaper than buying behind the counter as a customer, but I wasn't gonna spend this amount of money on something I could fix and possibly make better.

Here comes the interesting part...
I started sourcing the correct bearings for the AG. Also bought all gaskets and lubricants etc. Total cost of new parts was around 150EUR. I do all my work on my car myself so there aren't any labor costs.
This thread helped alot, but I did some things differently based on my own experience with driveline rebuilding etc. http://forums.swedespeed.com/showthread.php?187388-Fixing-the-angle-gear

I also used more durable bearings on the pinion gear shaft. The ring gear bearings are the same. I also wrote down all the part numbers for the bearings, but I don't have them with me at the moment. I'll just edit the post in a few days and add the list here.

Bearings:
2x NACHI H-E32010J
1x SKF 32006 X/Q
1x TIMKEN 32007 XM

So some pictures as well:


new bearings


A lot of failed angle gears. Since I couldn't just take out the AG on my car, rebuild it and install because I need the car daily, I used two failed angle gears and made one out of them. Those that have worked or built differentials and such, know that the pinion and ring gear are made in pair. The tolerances between the teeth are as good as possible and using a pinion gear from one and the ring gear from another AG might cause a whining noise or something. I was aware of that, but I managed to adjust the backlash and preloads so that there is no whining, grinding or any noise. One of the angle gears had a stripped input shaft, so I used the pinion gear from that one. The other had a broken pinion gear due to a failed pinion shaft bearing. I got the ring gear with perfect input shaft from that one. I just used the case that was the least dirtiest.


new bearings on the ring gear shaft/input shaft


new bearings on the pinion gear shaft and all four new bearing races






grinded edge of the cover


special tool to set the preload on the ring gear bearings




and done. topped up with oil and ready to be installed






removing the failed AG


destroyed pinion shaft bearing. there was a lot of metal pieces and dust.



and almost done...


Now why did it fail and why do they fail in general?
This is a question that has been asked and answered many times. Maybe somebody has already come up with this idea, but I haven't seen it yet. And I've searched the world wide web...
The angle gear is no different than a conventional differential for example. Except missing the satellites and their frame... The durability depends on lubrication. Of course incorrect bearing preload and gear backlash can and will affect things, but for this discussion let's assume that these are correctly adjusted and within tolerances.
Now lubrication. Angle gear uses a method of lubrication called splash lubrication.



This means that as the car moves forward (I should point out that full lubrication works only driving forward) the ring gear as it spins, picks up oil between the teeth of the gear. This gear used to lubricate the surfaces between the point where the pinion and ring gear meet as well as to literally splash the oil up and around. Usually it is designed that the oil that is being picked up by the ring gear will splash against the pinion gear bearing and lubricate it.

The problem with the angle gear on our R's (and other Volvos) is the lack of lubrication on the pinion shaft bearings. Of course there is the stripped collar sleeve problem which can also destroy the input shaft of the AG. But if we would install let's say upgraded collar from PDV or use the welding method, then we would eliminate the spline stripping issue. After that it's only the angle gear that needs to stand up to the power.
This is possible if a little customization is made.

Here's a picture of a half the case of the AG. It is sideways but try to picture it around. The part that it is standing on (facing the floor) goes to the transmission side and the left part goes to the driveshaft.


The brown line is a rough estimation of the oil level as the angle gear sits on the car. This is just for illustration. Now as the ring gear spins (clockwise in this picture if driving forward), it picks up oil from the bottom. It is then splashed around and against the wall of the AG. The red arrow indicates the part and hole where oil should enter a channel and move towards the rearmost pinion bearing. There is also this metal piece held by two torx screws and acts as a guide. As the oil is being splashed from the bottom it should hit that guide and go into the hole. Here is the problem. If your imagination is good enough you'll notice that once it goes into the hole it must go up and then return from the other hole marked with a green arrow. We live in a world where you CAN'T fight gravity. Therefore the pinion shaft bearings never get enough oil. Based on my experience working as a Volvo tech and based on other peoples experience, I can say that IF the input shaft of the AG doesn't fail due to the failed collar sleeve, then it has always been a problem with the pinion bearings. Never has anybody witnessed failure of the ring gear bearings. I reckon if somebody has then it was a case of destroyed pinion bearings which lead to excessive pinion shaft play and therefore damaged the ring gear and its bearings.

Now how to solve this problem? I have put it all on paper and made drawings and made a plan so to say. The AG that I took out with the failed bearing (video above)
will be taken apart. Of course I will clean out all the metal filings and replace all the bearings etc. But I will also do something that I haven't seen being done before.
I've already ordered a Weldon high temp. resistant oil pump, an oil cooler that will be mounted somewhere under the car (don't know where yet), armored oil lines and fittings and a filter. I will also drill a hole in the bottom of the AG and install a drainhole so I can easily replace the oil and filter whenever I feel the need.
I will also drill holes in the AG for the oil input and output bungs. Input would be directly at the pinion gear bearings or between the bearings to be exact. Output would be somewhere at the bottom. Of course the oil quantity is going to be higher since there is piping, cooler, pump, filter and finally the AG itself, but that's not an issue. I'm convinced that the angle gear could sustain more power and be more durable if the lubrication was sorted out. I mean what's bad about cooled oil that is filtered and being pumped at the place that is seeing little to no oil at all. The splash lubrication method would still be working since I'll try to measure out the amount of oil that even when the pump is running, the angle gear still has the correct amount of oil at the bottom.

I'll update this thread as the progress goes with text and pictures, BUT even when I'm finished with the AG and all of it's new components I will not install it until the rebuilt AG that is under my car at the moment fails. There's no need until then. But knowing the design flaws and history of the Volvo AG, I know it will fail eventually...

Thanks for reading everybody. Hope this turns into a constructive discussion.
I'm sorry if my English is not good here and there...


Enjoy your day all!

Gustav
 

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Very cool and detailed explanation Gustav... I think this has a lot of potential! Now, please keep us updated on the details. I'm sure there are many more that just me who would like to improve the angle gear especially as we keep increasing power levels.

You're absolutely right about the angle gear design. This is honestly the first time I've seen pictures of this level of detail and it looks much like a typical ring/pinion from a normal rear axle in a mustang... which I have personally installed so I'm fairly familiar with them. If the gears are hard enough and backlash/preload is set properly like you explained, then fundamentally these should be able to handle plenty of power when properly lubricated.
 

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Thankyou for the great pictures. Too bad Volvo did not add a drain plug. Keep us posted with your progress and pictures.
 

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Awesome! Thank you for this! I just realized I can source the nachi bearings for next to nothing if I had the correct P/Ns, please update when you can. :)

Sent from my SCH-I545 using Tapatalk
 

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Discussion Starter · #7 ·
I updated the first post with bearing part numbers.
 

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I think it funny that people think a upgraded collar is going to solve all our problems. My collar as well as some others was fine and the splines on the AG itself were stripped. So if this can happen with butter soft stock collar it definitely will happen with a harder one
 

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Discussion Starter · #10 ·
I think it funny that people think a upgraded collar is going to solve all our problems. My collar as well as some others was fine and the splines on the AG itself were stripped. So if this can happen with butter soft stock collar it definitely will happen with a harder one
I'm not expert, but as far as I know the so called upgraded collar has much tighter tolerances and fits better. There's some play at the angle gear side between the splines and that together with lack of lubrication on the splines and moisture etc causes problems. Then there is welding.

My point is whatever method people choose to reinforce the collar gear, there is still a problem with the angle gear itself. I'm just trying to make things better for myself and for the community :)
 

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Discussion Starter · #12 ·
I do my own everything on the car, but what yellow line? We have a special lift with cameras and mirrors for that...
 

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Whoops i guess it's just the grout for the concrete :p

I know alot of people use a 90 degree line to do toe alignments and wasn't sure if that's what the line was for. Obviously alignment tools are much more precise.
 

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Nominated for post of the month.
 

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I'm not expert, but as far as I know the so called upgraded collar has much tighter tolerances and fits better. There's some play at the angle gear side between the splines and that together with lack of lubrication on the splines and moisture etc causes problems. Then there is welding.

My point is whatever method people choose to reinforce the collar gear, there is still a problem with the angle gear itself. I'm just trying to make things better for myself and for the community :)
Agree, I think the upgraded collar is beneficial not only from the hardness but also the fit... any slop in this joint will only lead to problems. Together with this angle gear oiling improvement, I think we will finally have a decent chance at a robust setup.
 

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So, I was looking at what the OP said about oil needing to defy gravity. That makes a lot of sense. Is there any possibility that we could modify the oil passage. Like fill the old lower entry and drill a new passage up higher above the old one? Maybe drill and weld in an aluminum tube to start the flow higher? I don't know if the splash is big enough to make it work, but I would think that it could still oil it well. Another thought I had about angle gears is the design. It seems like they could have used a modified dropout differential with a spool and no connecting splines. That's purely just for thought. Anyone know the gear ratio in the angle gear?
 

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Discussion Starter · #17 ·
So, I was looking at what the OP said about oil needing to defy gravity. That makes a lot of sense. Is there any possibility that we could modify the oil passage. Like fill the old lower entry and drill a new passage up higher above the old one? Maybe drill and weld in an aluminum tube to start the flow higher? I don't know if the splash is big enough to make it work, but I would think that it could still oil it well. Another thought I had about angle gears is the design. It seems like they could have used a modified dropout differential with a spool and no connecting splines. That's purely just for thought. Anyone know the gear ratio in the angle gear?
I dont think drilling a hole higher would help since the oil has to go even further upwards and the make even sharper turn and find its way to the rearmost bearing. Also if you look at the picture right above the video, you'll notice that there isn't much room next to the pinion gear. As well as you still need that little metal piece to guide the oil. I think the angles would be way too extreme. I don't know much about fluid dynamics, but common sense tells me that it won't work in this physical world...

As for the gear ratio, I can count the teeth on the gears when I have spare time...
 

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Is there a problem with just filling the unit with more oil? If the unit was filled something like half way up, the bearings would always be sitting in oil.
 

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You would have to fill it substantially. Would more then likely pour out the seals let alone the drag.
 

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Discussion Starter · #20 ·
I think it would start to leak. Splash lubrication wouldn't work the way its supposed to. Also there is a possibility of building oil foam and with that there is cooling properties lost.
 
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