MQ250 (02A/02J/0A4/02S) differential differences + Diff Pin Removal and Replacement

[@guidoratefuchs]

Awesome footage, watched all of your videos and am now building my own el cheapo 6-speed box with no prior expertise at all. Surprisingly, my 02s pulled from an early Passat B7 came with a 02j differential in it.

[@TheOlehal]

Are the synchros brass on 0a4 looking to replace the flywheel to solid. Clutch starting to slip

[@dzelpwr]

Yes, they are all brass and fairly thick. Exceedingly rare to see them crack or break even when converted to single mass.

[@markhorner717]

In need of some help with my lifted mk5 jetta tdi 0A4 GQQ. Im looking to swap entire differential from mk4 jetta,golf,beetle 2.0 to take my 3.39 ratio to 4.235. Do you know if that will work. Thanks for any help

[@dzelpwr]

Yes, you can take the ring and pinion from a Mk4 2.0 and put it in your 0A4. You could also just use the Mk4 transmission as-is. Either keep the vehicle speed sensor installed or find an m16x1.50 plug to fill the hole (pretty sure that's the size, off the top of my head). Then you'd also need the Mk4 shift bracket to hold the cables on top the transmission. Doing that will lengthen the shift throw, though. The internal mechanisms of the 02J make for longer throws than the 0A4 and 02S.

[@GavinS6]

do you have any information on 0A4 gearbox bearings? i've searched all over for part numbers and can't seem to find a parts list. i have some bearings but not all of them and need to find the numbers of some of the needle bearings.

[@dzelpwr]

Certainly. The early boxes use most of the same bearings as the 02A/02J. The differential bearing part numbers are different, but you can use 02A/02J diff bearings in the 0A4 no problem (which is kind of what I did here). The needle bearing for reverse, where it presses into the bellhousing is the same. The needle bearing for the other end of the reverse selector shaft is, according to VW, only available as part of the upper bearing support assembly. That part number *is* 0A4 specific. The straight roller bearing that presses into the back of the case should be the same on early 0A4s as it is a 02J. But as you get to the later 0A4s (like the 2018 and newer versions, much like the 02S I have here which uses a lot of 0A4 parts) the small pinion bearing, whose outer race presses into the bellhousing changes. The straight roller bearing that presses into the gearbox case (or "rear case half" as I like to call it) is also very different on the later 0A4s/02S.

[@mistron71]

Just watched your new wavetarc lsd video and now this one, I wanted to know your opinion on the lsd conversion kits made by racingdiffs, they currently just make them for 02a and I have a 02s, but this year they will release more gearboxes. I'm planning on making the mod myself here in spain, the wavetrac is 1500€ and the other kit is 200€, I understand that the performance won't be the same but if it's 75% of the wavetrac I can't justify spending more than a grand extra.

[@dzelpwr]

I have zero experience with those. It looks a little hokey, if I'm being honest. You're also still using the original differential, which has its own weak point--the roll pin holding the main shaft for two of the spider gears. Going to a proper, full limited slip diff is substantially sturdier than the stock diff could ever hope to be, with or without an add on kit like the one you mention. For me, it's either leave the original diff as it is, or put in a proper limited slip.

[@Kaos_roshi]

would an 02S from a 2019 Jetta transmission gearing be the same as a say 2010 2.5 golf 5 speed but with just the extra 6 speed?

[@dzelpwr]

It will be taller all around. Vast majority of 2.5 5 speeds have a shorter final drive. 3.65 vs. this gearbox's 3.39. The 5th gear in most of those 2.5 gearboxes is a 0.838 or so. The combination of 3.65 FD and 0.838 5th gear puts you at about 3300 RPM at 80 MPH (GPS speed, not the overly optimistic instrument cluster's reading, which is probably ~4 MPH higher than what you're actually doing). With the 02S 6 speed in question here, on top of the taller 3.39 final drive also has a 0.77 5th gear and a 0.625 6th gear (!), this means at 80 MPH you would be doing 2800 in 5th gear and a hair under 2300 RPM in 6th gear.

[@Kaos_roshi]

good information ! thank you!@@dzelpwr

[@Kaos_roshi]

1-4 gears are the same but with a taller final drive then ? or are they different too@@dzelpwr

[@dzelpwr]

@@Kaos_roshi not exactly the same, but pretty close for 1st through 3rd gear. But bear in mind that the shorter final drive makes it as though all gears are shorter. I found a VIN number for a 2010 Golf 2.5 5 speed, it came back in my parts program as having a KPF code 0A4 family 5 speed. Some of the later 5 cylinders I believe do use a taller 3.39 final drive, but in this case, the KPF is a 3.65 as mentioned above. Here is what the rest of the gearing looks like: 3.65 final drive 3.77 1st gear 2.12 2nd gear 1.36 3rd gear 1.03 4th gear 0.838 5th gear The TDZ and TKR 02S 6 speeds have the following: 3.39 final drive 4.11 1st gear (shorter than normal) 2.12 2nd gear (identical) 1.36 3rd gear (identical) 0.97 4th gear (taller) 0.77 5th 0.625 6th