MK4 TDI 0J2 Transmissions, alternatives

AndyBees

Top Post Dawg
Joined
May 27, 2003
Location
Southeast Kentucky
TDI
Silver 2003 Jetta TDI, Silver 2000 Jetta TDI (sold), '84 Vanagon with '02 ALH engine
Guys, these transmissions are getting old. Many of them were not maintained well. The hub (and slider) on 5th gear is prone to wear even if the oil level was maintained properly. The little fine splines on 5th gear are also prone to wear. I am sure most of you are aware of these short-comings (for the lack of a better term).

Anyway, for the sake of discussion, here are a few questions/thoughts.

1. Has anyone upgraded 5th gear in an 0J2 from a 1.8T gasser? If so, results... satisfied or not
2. Has anyone considered "welding" the 5th gear with the worn splines? Is it possible? How could it be kept "centered and square" for welding?
3. Has anyone used the 5th gear hub and slider from a 1.8T 0J2 transmission? (I have and it works just fine.)
4. Have any of you disassembled and done a rebuild of the 02J transmission? If so, where did you get the parts?
5. Is there another acceptable transmission for an MK4 besides the ones mentioned here?

Thoughts?
 

STDOUBT

Veteran Member
Joined
Jul 30, 2007
Location
Portland, effing Oregon
TDI
dos jettas
If so, where did you get the parts?
I have not. Nor am I looking forward to it necessarily.
But I want everyone on here to give these guys lots of money so they're still around when I need to:
I ordered the "5 Speed MANUAL TRANSMISSION Technical Documentations For OVERHAULING 02J Volkswagen transaxle"
and they sent it to me for free. Refunded me after delivery saying essentially it's complimentary. This will be my go-to when the need arises, if ever. If I was loaded, I would just buy "all the things" for the shelf.
 

AndyBees

Top Post Dawg
Joined
May 27, 2003
Location
Southeast Kentucky
TDI
Silver 2003 Jetta TDI, Silver 2000 Jetta TDI (sold), '84 Vanagon with '02 ALH engine
About 15 years ago, I replaced the transmission in a 2000 NB gasser for a friend. It belonged to his son. Seems there was a pin/dowel or something that come loose in the diff that ended up knocking a hole in the bottom of the trans. Anyway, I robbed out all the good stuff from the broken transmission, mostly 5th gear parts. I've since used those parts.

I replaced the original transmission in my formerly owned 2000 Jetta with one I picked up in Michigan, also about 15 years. Recently, my son (the owner), discovered oil slinging out of the left side flange seal. I only got about 1 quart when I drained it. I installed new seals, oil, CV Joints, etc., but have not put it on the road yet. It is likely trashed too.

I've passed on several gasser transmissions over the last few years for cheap. Now they are not as readily available and the prices are no longer cheap.
 

AndyBees

Top Post Dawg
Joined
May 27, 2003
Location
Southeast Kentucky
TDI
Silver 2003 Jetta TDI, Silver 2000 Jetta TDI (sold), '84 Vanagon with '02 ALH engine
Wow! I've found two EGR 0J2 transmissions for $200 each. Unknown miles per the seller.
Hmm. I may just take them both.
 

Matt-98AHU

Loose Nut Behind the Wheel Vendor
Joined
Apr 23, 2006
Location
Gresham, OR
TDI
2001 Golf TDI, 2005 Passat wagon, 2004 Touareg V10.
I saw him mentioning that in another thread today or yesterday, really interested in the idea... Especially if it just bolts up...
Almost does. Have to fabricate adapter brackets for the shift cable holder, or get ahold of @caffeine for the adapters he 3D prints.

For 2002 and newer cars with immo III clusters you can use @gmenounos' KW1281test to hack the cluster to pick up vehicle speed from CAN bus, as these transmissions do not have a vehicle speed sensor.

For 2001 and older Mk4s, caffeine also has a neat setup that involves a tone wheel that goes on the driver side axle and a bracket to hold a magnetic pickup sensor to generate a vehicle speed signal to send to the cluster as an option.

It's either that or you do it the extra hard way like I did for my 2001 Golf and swap the bellhousing out for a 02J bellhousing plus an 02J-B limited slip diff that is machined to accept the Mk4 vehicle speed sensor drive gear.

Once that stuff is done, then yes, the 02S comes in and out just like an 02J. Can still use the same clutch & flywheel, starter, shift linkage bits, clutch hydraulics etc.

And obviously being a lot newer production transmission, much more likely to get a nice long life out of it.

BUT, it needs to be emphasized to those who are used to how gear oil changes work on an 02J, anything newer in that MQ250 family architecture needs special attention to the procedure for draining and filling the transmission. Starting with the earliest 0A4 5 speeds in the Mk5s, the among the items altered in the bellhousing in the change from 02J to 0A4 was an extra bit of casting was put on the 0A4s below where the pinion shaft goes into the case, and it effectively blocks natural gravity drainage of oil into the differential space. This is why when you try to drain one of these transmissions with just the drain plug under the diff, you only get a small amount of fluid out. You need to remove one of the lower shift pins in the other case half to get most of the remainder of the gear oil out.

This also means you CANNOT rely on the fill plug for accurate oil level. You have to make sure all the oil is effectively drained out using the above procedure, and then fill it with oil with the precise amount VW prescribes from a point higher than the fill plug because the drainage into the diff region is so poor.

On a 0A4 5 speed, 2 quarts is about right. on a 02S 6 speed, more like 2.25 quarts.
 

JonA

Veteran Member
Joined
Feb 25, 2015
Location
Rhode Island
TDI
2002 Golf TDI M/T
Almost does. Have to fabricate adapter brackets for the shift cable holder, or get ahold of @caffeine for the adapters he 3D prints.

For 2002 and newer cars with immo III clusters you can use @gmenounos' KW1281test to hack the cluster to pick up vehicle speed from CAN bus, as these transmissions do not have a vehicle speed sensor.

For 2001 and older Mk4s, caffeine also has a neat setup that involves a tone wheel that goes on the driver side axle and a bracket to hold a magnetic pickup sensor to generate a vehicle speed signal to send to the cluster as an option.

It's either that or you do it the extra hard way like I did for my 2001 Golf and swap the bellhousing out for a 02J bellhousing plus an 02J-B limited slip diff that is machined to accept the Mk4 vehicle speed sensor drive gear.

Once that stuff is done, then yes, the 02S comes in and out just like an 02J. Can still use the same clutch & flywheel, starter, shift linkage bits, clutch hydraulics etc.

And obviously being a lot newer production transmission, much more likely to get a nice long life out of it.

BUT, it needs to be emphasized to those who are used to how gear oil changes work on an 02J, anything newer in that MQ250 family architecture needs special attention to the procedure for draining and filling the transmission. Starting with the earliest 0A4 5 speeds in the Mk5s, the among the items altered in the bellhousing in the change from 02J to 0A4 was an extra bit of casting was put on the 0A4s below where the pinion shaft goes into the case, and it effectively blocks natural gravity drainage of oil into the differential space. This is why when you try to drain one of these transmissions with just the drain plug under the diff, you only get a small amount of fluid out. You need to remove one of the lower shift pins in the other case half to get most of the remainder of the gear oil out.

This also means you CANNOT rely on the fill plug for accurate oil level. You have to make sure all the oil is effectively drained out using the above procedure, and then fill it with oil with the precise amount VW prescribes from a point higher than the fill plug because the drainage into the diff region is so poor.

On a 0A4 5 speed, 2 quarts is about right. on a 02S 6 speed, more like 2.25 quarts.
Bookmarking this for my ever-growing todo list, thanks so much for sharing!
 

AndyBees

Top Post Dawg
Joined
May 27, 2003
Location
Southeast Kentucky
TDI
Silver 2003 Jetta TDI, Silver 2000 Jetta TDI (sold), '84 Vanagon with '02 ALH engine
I picked up the Transmission in North Carolina today (see Post #6). The guy had two. I told him I wanted one of them. On the way down, I decided that I'd take them both. I got to his place before he come home from work. While I was waiting a guy drove up from Lynchburg, VA (4 hour drive, he said). As we were talking I told him why I was there and that I had decided to take both transmissions. He said that was what he had planned to do as well....LOL

Anyway, we each got ourselves a transmission. I let him have the one with a starter on it and CV joints (axles had been torched off).

Also, I picked up a nice never installed metal belly pan with assembly components for a very good price.
 

jmodge

Top Post Dawg
Joined
Jun 18, 2015
Location
Greenville, MI the winter water wonderland
TDI
More than I need, less than I want
I used stud and bearing loctite on worn 5th gear splines and it held up fine, didn’t seem to vibrate either. They weren’t totally stripped, but worn enough that they were loose. I put a good gear on and let it setup a couple days. Eventually something else happened to it and I replaced the whole transmission.
 

AndyBees

Top Post Dawg
Joined
May 27, 2003
Location
Southeast Kentucky
TDI
Silver 2003 Jetta TDI, Silver 2000 Jetta TDI (sold), '84 Vanagon with '02 ALH engine
Well, I hot pressure washed the transmission. It wasn't bad dirty, so, it cleaned up nicely.

Anyway, generally an "as is" deal is, well, just that, an as is deal.
So, in this case, I sort of got screwed. 5th gear and the shifting assembly had been robbed out. I guess I should have taken the time to remove the end cap for an inspection.

The good news is: The price was extremely right (very cheap). The splines on the end of the two shafts look perfect. And, the oil looked clean, which may or may not be an indication of anything, good or bad. The shifting mechanism seemed to be tight and all there.

So, this winter, on a cold day, I'll turn the heat on in the garage and commence my first rebuild of an 02J transmission. I do have a complete 5th gear set, including the shifting mechanism from a gasser transmission. The shifting mechanism is the same. So, besides bearings, I'll need to source a 5th gear set, maybe an upgrade in ratio.
 
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Matt-98AHU

Loose Nut Behind the Wheel Vendor
Joined
Apr 23, 2006
Location
Gresham, OR
TDI
2001 Golf TDI, 2005 Passat wagon, 2004 Touareg V10.
Well, I hot pressure washed the transmission. It wasn't bad dirty, so, it cleaned up nicely.

Anyway, generally an "as is" deal is, well, just that, an as is deal.
So, in this case, I sort of got screwed. 5th gear and the shifting assembly had been robbed out. I guess I should have taken the time to remove the end cap for an inspection.

The good news is: The price was extremely right (very cheap). The splines on the end of the two shafts look perfect. And, the oil looked clean, which may or may not be an indication of anything, good or bad. The shifting mechanism seemed to be tight and all there.

So, this winter, on a cold day, I'll turn the heat on in the garage and commence my first rebuild of an 0J2 transmission. I do have a complete 5th gear set, including the shifting mechanism from a gasser transmission. The shifting mechanism is the same. So, besides bearings, I'll need to source a 5th gear set, maybe an upgrade in ratio.
Cascade German has had the .681 5th gearsets repop'd. Really is a great ratio, a lot more flexible in the 55-60 mph range than the .658 is.

80 MPH goes from just under 2800 to just under 2500. A lot more flexible feeling than the taller gear options for sure.
 

AndyBees

Top Post Dawg
Joined
May 27, 2003
Location
Southeast Kentucky
TDI
Silver 2003 Jetta TDI, Silver 2000 Jetta TDI (sold), '84 Vanagon with '02 ALH engine
I have not. Nor am I looking forward to it necessarily.
But I want everyone on here to give these guys lots of money so they're still around when I need to:
I ordered the "5 Speed MANUAL TRANSMISSION Technical Documentations For OVERHAULING 02J Volkswagen transaxle"
and they sent it to me for free. Refunded me after delivery saying essentially it's complimentary. This will be my go-to when the need arises, if ever. If I was loaded, I would just buy "all the things" for the shelf.
Well, the big wear item, Hard Parts does not offer on their parts list.

The 5th gear Hub and Slider are major wear items. Every 02J transmission that I've inspected or replaced, the 5th gear Hub/Slider assembly was wore badly. The only thing in Hard Parts list that I saw offered for 5th gear is a "used or reconditioned" Synchronizer Ring. Really? How could a worn Synchronizer Ring be reconditioned? The inside of the Synchronizer Ring, where it rides on the gear Cone, is the wear surface. The teeth virtually do not wear.

Anyway, in my opinion, a new 5th Gear set of any ratio is basically useless if the Hub and Slider are badly worn.

So, I'd rather put my cash on a new Hub/Slider assembly and use the old OE gear set, including the worn Synchronizer Ring.

At what point do you put a $499.95 "Bearing Kit" for your transmission? If all those bearings are worn bad enough to replace them, the 5th gear assembly (all the parts mentioned here) is worn more!

I would buy a "complete" 5th gear assembly in a heart-beat if they offered it. (5th gear set, hub, slider, Synchronizer, bearing and gasket).

In MyTurboDiesel, there is a good documentation of these transmissions (and others for comparison). There may be something similar here in the TDI Club, but I did not find it.
.
 

Matt-98AHU

Loose Nut Behind the Wheel Vendor
Joined
Apr 23, 2006
Location
Gresham, OR
TDI
2001 Golf TDI, 2005 Passat wagon, 2004 Touareg V10.
Well, the big wear item, Hard Parts does not offer on their parts list.

The 5th gear Hub and Slider are major wear items. Every 02J transmission that I've inspected or replaced, the 5th gear Hub/Slider assembly was wore badly. The only thing in Hard Parts list that I saw offered for 5th gear is a "used or reconditioned" Synchronizer Ring. Really? How could a worn Synchronizer Ring be reconditioned? The inside of the Synchronizer Ring, where it rides on the gear Cone, is the wear surface. The teeth virtually do not wear.

Anyway, in my opinion, a new 5th Gear set of any ratio is basically useless if the Hub and Slider are badly worn.

So, I'd rather put my cash on a new Hub/Slider assembly and use the old OE gear set, including the worn Synchronizer Ring.

At what point do you put a $499.95 "Bearing Kit" for your transmission? If all those bearings are worn bad enough to replace them, the 5th gear assembly (all the parts mentioned here) is worn more!

I would buy a "complete" 5th gear assembly in a heart-beat if they offered it. (5th gear set, hub, slider, Synchronizer, bearing and gasket).

In MyTurboDiesel, there is a good documentation of these transmissions (and others for comparison). There may be something similar here in the TDI Club, but I did not find it.
.
Unfortunately the dealer is the only source for those parts, and they are not cheap, especially the synchro hub and slider.

Vendors here to offer them, but again, sourced through the dealer. Cascade German appears to list it for $398 currently. Dealer retail is North of $500! Part number 02J311241F.

They aren't exactly plentiful in VW North American warehouses either, so if you or the vendor you buy it from doesn't have it on the shelf and needs to buy another through the dealer network, it may take a bit of time to get it.

I've got an exceptionally badly worn one that's now just a fidget toy on my desk. Came out of the "free" 2003 wagon deegingerkid and I picked up last year. One of a couple cars I've experienced where if you don't get it out of 5th gear before coming to a stop, you won't get it out of 5th at all!

Unfortunately the dealer is the only source for those parts, and they are not cheap, especially the synchro hub and slider.

Vendors here to offer them, but again, sourced through the dealer. Cascade German appears to list it for $398 currently. Dealer retail is North of $500! Part number 02J311241F.

They aren't exactly plentiful in VW North American warehouses either, so if you or the vendor you buy it from doesn't have it on the shelf and needs to buy another through the dealer network, it may take a bit of time to get it.

I've got an exceptionally badly worn one that's now just a fidget toy on my desk. Came out of the "free" 2003 wagon deegingerkid and I picked up last year. One of a couple cars I've experienced where if you don't get it out of 5th gear before coming to a stop, you won't get it out of 5th at all!



I used it as an excuse to do the first 02S 6 speed swap of mine without hybridizing the 02J bellhousing. Made a couple adapter brackets, hacked the cluster for VSS via CAN and bolted the sucker in. At less than $900 for a used, low mile 6 speed that otherwise uses all 5 speed ancillary parts, it's hard to say no to. The cost of a new 5th gear set plus a new 5th synchro hub quickly gets you to the cost of a good used transmission that's a lot newer, with far fewer miles and has an additional gear... When I put it that way in my head, it became a no-brainer, really.

Yes, I could have fixed that gearbox easily without removing it, but it needed to come out for a clutch and flywheel anyway, so why not just go for the 02S as a replacement instead of spending nearly the same amount of money for a taller 5th gear and new 5th selector/synchro hub? That's the way I saw it.

I used it as an excuse to do the first 02S 6 speed swap of mine without hybridizing the 02J bellhousing. Made a couple adapter brackets, hacked the cluster for VSS via CAN and bolted the sucker in. At less than $900 for a used, low mile 6 speed that otherwise uses all 5 speed ancillary parts, it's hard to say no to. The cost of a new 5th gear set plus a new 5th synchro hub quickly gets you to the cost of a good used transmission that's a lot newer, with far fewer miles and has an additional gear... When I put it that way in my head, it became a no-brainer, really.

Yes, I could have fixed that gearbox easily without removing it, but it needed to come out for a clutch and flywheel anyway, so why not just go for the 02S as a replacement instead of spending nearly the same amount of money for a taller 5th gear and new 5th selector/synchro hub? That's the way I saw it.
 
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