Porsche 914 transaxle questions

[Electroman]

I tried posting this thread in a 914 specific forum on a Porsche website, long story short they didn't seem to want to answer my questions. all the responses I got were to basically take it to a professional. so...

I'll ask here. I know most of the guys here work with VW transmissions but seeing as they are very slimier I hope I can get some help here on the shop talk forums where I always get answers.
first I had some questions bout early vs late brake band setups for the synchronisers but I found the answer to that on a transmission website. so one of my main questions was how to judge if a bearing is reusable or not. I understand to look for major defects, broken cages, weird ware patterns, ect. but what if a bearing looks almost new. how can I tell if it should be replaced or cleaned and reused. for instance here is my pinion bearing, to me this looks good to go.



besides that I would really just like some second opinions on if some parts could be reused or if I should just go ahead and replace them. like here is the dog teeth for third gear. first and second are trash fourth and fifth look great, but I'm not sure about third. sorry for the quality of the picture took it with my phone. I can take anther that much better if need be.



also the 2nd 3rd slider I'm pretty sure it could be cleaned up a touch with a file and put back in the trans.



lastly for now the 1st Revers slider. this one should probably be replaced, but I figured I would get a second opinion.




thanks in advance.

[Pablo2]

Joshua .. While the bearing photo look good, we should take a look at the race.

While I have had success redressing laid-over edges of operating sleeves, yours are worn beyond what I would consider serviceable. It's the inside dimension of the wear zones that are critical to proper synchro compression.

3rd gear engagement teeth must be replaced. There are some tricks to this (otherwise the new teeth will just work themselves off).

[Electroman]

Ill have to take some pictures of the bearing races, but they all look good.

I was pretty sure the 1st - Reverse sleeve was bad just wanted to double check. as far as 2 -3 goes I wasn't sure if it could be salvaged, I thought replacing it would be a good idea but wasn't sure.

same with the 3rd gear teeth. I have all the tools and know how to get them replaced I just wanted to see if it could be saved.

that being said Ill get some pictures of the main bearings and their races and get them on here ASAP.

[Pablo2]

Removing the old engagement teeth partially destroys the factory swaging, as does installing the new teeth. The only way to restore this is electronic peening, with modified spot welder. You could send that idler to my associate in Boulder, and he'd do that for you. It's very risky to skip this step.

The other issue with replacement teeth is the 9* angle ground for proper synchro ring seating. This is an unfinished angle, meant to be machined as a last step (after installing teeth), to guarantee concentricity. There is no easy answer to this. Most guys just install the teeth, and wonder why the new synchro ring is too compressed. Jerry Woods has set up to grind this angle after installation, but @ $30 per gear.
http://images.thesamba.com/vw/gallery/pix/1116834.jpg

[Electroman]

as far as the 9* angle ground on the back of the teeth, that I know about and have a friend of a friend that's local to me that says hes got the equipment to do it. but about the "factory swaging", that I have never seen anybody mention before. because the dog teeth and the gear have interlocking teeth on their press fit surfaces nobody i have talked to has ever done anything to keep them together. Do you have any more details about this, as I want to make sure I don't miss something important.

anyway on to the rest of the bearings. first off these pictures aren't the best quality ( took them with my phone) and it makes some of the races look much worse than they do in person. all the bearings and races feel smooth with no worn groves or anything that I can find.

I already put up a picture of the differential end pinion bearing, so here is its race.


this is the input shafts differential end bearing


and its race


this is the pinion shafts bearing in the intermediate plate, haven't cleaned this one all the way yet


and its race


input shaft intermediate plate bearing, also not fully cleaned


and its race


that's all the main bearings. to me the intermediate plate bearings look like they are in great condition, but based on the greying of the races for the main bearings I'm wondering if they might need to be replaced. hope not because the bearings themselves look great. anyway thanks for the help so far.

[Pablo2]

You're right .. the photos make those races look terrible. I have little luck making a judgement call with anything less than a 10X microscope .. but "greying" of the races suggests small pits, which eventually become large pits. So it's your call. Is this being built for 150K miles, or 50K miles?

The 9* angle should be done after the new teeth/dog ring are installed, so that they're indexed from the gear bore. Accuracy isn't possible otherwise (which is of course the reason replacement teeth come like that).

At the factory, a smack with a special 50-ton swaging tool on the ends of the splines is what retains the engagement teeth. You cannot duplicate this with a chisel. While it's a hassle to do, dremeling a split into the old dog ring allows removal without too much damage to the factory swaging. Heating the new dog ring and pressing them onto a frozen gear also helps avoid damaging this retaining swage. If you do this, you can probably skip use of the spot welder (which isn't really used to weld, but rather to slightly deform the ends of splines. Actual welding doesn't work). The issue of teeth walking off the gear is most critical with smaller diameter gears, in which the dog ring isn't fully supported around the outer perimeter (on the backside) .. but I have seen it on all gears (with replacement teeth) at one time or another.

Your original photo of the gear in question appears to show scuffing on the gear teeth themselves .. although this could certainly be attributed to poor focus.

[Electroman]

ill have to pull out a magnifying glass and take a closer look at the races now that I think I understand what I'm looking for exactly.

about the swaging now it makes sense why my friend was telling me to heat the teeth before pressing them onto the gear. now it all makes sense.

about the gears ya that's basically the picture. the faces of the gears are almost a mirror finish. next time Ill pull out my good camera to take the pictures and not my phone. thank you for all of the help.