01M to 02j swap questions

[MaverickH1]

It seems like the best way to go about doing a swap to an 02j is to simply purchase a parts car and steal parts off of it. Is the only way to do this to find a manual transmission TDI? Or would a manual transmission gas MK4 Jetta work equally well while ALSO being significantly easier and cheaper to find? Does it have to be a specific year of MK4 Jetta?

Is there a better transmission to use? For example, on Humvees for example the 3 speed transmission from the 80s is identical to the 4 speed transmission of the 90s, and it's possible get the next generation transmission bolted up with other little changes such as crossmembers, driveshafts, etc. I didn't know if the next generation 6 speed manual from the newer TDIs would be a similar thing or not.

I landed a great condition 150k mile 2002 Jetta TDI for $1000 a little over a year ago. It didn't start, all it needed was one of the o-rings on the injector pump replaced. It has been saving me money on my 30 mile commute since and has already paid itself off from the savings.

The only down side is that it has the 01M transmission. It started to shift hard in the final gear shift from 3 to 4. It also will drop in RPM while in 3rd gear as if it slowly and smoothly shifted... and then it'll do the thing where it feels like it takes forever to shift into 4th and jolts when it finally does. The changing in RPMs while still within a gear is so extreme that when I was counting gear changes during trouble shooting I was certain it was a 5 speed transmission, which obviously it isn't. it exhibits behavior like that in other gears *sometimes*.

I decided to do a fluid/filter change. Everything looked decent inside, of course, the filter was probably original to the car based on the date on the filter. I'm just never going to trust the 01M transmission, basically. So instead of throwing $500 at a valve body, and other random fixes that have no guarantee of working, it feels like it'd be smarter to just buy a $1000 parts car and swap everything over and replace wear parts at the same time.

I'd like to get the transmission issues figured out before I sink more into the car and do the timing belt that is due in ~15,000 miles.

If the car is benched, I'll probably rip the engine out of it and make a street legal go cart or a boat out of it or do a conversion on another vehicle or something. I love these engines!

 

[Matt-98AHU]

A 4 cylinder gas transmission will infact bolt up and work with the TDI, but it will be geared WAY shorter than the TDI transmission.

Most of the gas transmissions use a 0.84 5th gear. The TDI a 0.76 (rounding up to the nearest hundredth).

To top it off, you also have wildly varied final drives:

4.24 final drive for most of the 2.0 8V transmissions
3.94 final drive for early 150 hp 1.8 turbos
3.64 final drive for later 180 hp 1.8 turbos
3.39 final drive for the TDIs...

So, easy enough math. Multiply your 5th gear ratio by the final drive ratio, you get the total gear reduction in 5th gear on the highway. Given that the TDI has both the tallest 5th gear and tallest final drive, it's going to be a pretty substantial difference in RPM...

For example, the 2.0L final gear reduction in 5th would be about 3.56:1

The TDI is a little more than 2.57:1

How else do I put it? Well, it's the difference between your engine doing 4000 RPM at 80 MPH in 5th gear vs. doing 2800 RPM in 5th gear.

Also, the 1.8T transmissions will have 108 mm axle flanges where the 2.0 and TDIs use 100 mm. So, there are different axle considerations as well. Easiest just to stick with the correct TDI transmission with 100 mm flanges and matching axles...

The results of using a shorter geared transmission aren't going to do fuel economy any favors... or noise levels on the highway, that's for sure.

 

[csstevej]

On a side note to this , I’ve kept my auto axles and just replaced the 100mm flanges with 108mm….took all of ten minutes when I did my swap.

 

[benmarks]

"Is there a better transmission to use?"

Just FYI, you can also buy the 02M 6-speed gearbox from places like Korwerks or Darkside. Darkside even sells a kit for auto-to-manual swap and, even though they're in the UK, their shipping is reasonable.

Whether 6-speed is better is open to opinion, but it is a bolt-on option.

Almost anything is better than the 01M, which I'd almost consider a wear item

 

[Nero Morg]

I've heard from a few people, one being a vendor, that the 6 spd isn't as strong as the 5 spd, and getting the starters are a little more unique. Both are good options, but must be from a tdi.

 

[MaverickH1]

A 4 cylinder gas transmission will infact bolt up and work with the TDI, but it will be geared WAY shorter than the TDI transmission.

Most of the gas transmissions use a 0.84 5th gear. The TDI a 0.76 (rounding up to the nearest hundredth).

To top it off, you also have wildly varied final drives:

4.24 final drive for most of the 2.0 8V transmissions
3.94 final drive for early 150 hp 1.8 turbos
3.64 final drive for later 180 hp 1.8 turbos
3.39 final drive for the TDIs...

So, easy enough math. Multiply your 5th gear ratio by the final drive ratio, you get the total gear reduction in 5th gear on the highway. Given that the TDI has both the tallest 5th gear and tallest final drive, it's going to be a pretty substantial difference in RPM...

For example, the 2.0L final gear reduction in 5th would be about 3.56:1

The TDI is a little more than 2.57:1

How else do I put it? Well, it's the difference between your engine doing 4000 RPM at 80 MPH in 5th gear vs. doing 2800 RPM in 5th gear.

Also, the 1.8T transmissions will have 108 mm axle flanges where the 2.0 and TDIs use 100 mm. So, there are different axle considerations as well. Easiest just to stick with the correct TDI transmission with 100 mm flanges and matching axles...

The results of using a shorter geared transmission aren't going to do fuel economy any favors... or noise levels on the highway, that's for sure.

Perfect. I was expecting the gas parts car to require something like a different computer or other electric items, but I was most worried about simple and non-obvious mechanical ones.

It obviously makes sense for VW to gear the transmissions differently due to the different power curves and substantially different RPM red lines, but I was having a hard time finding any specifics.

I will narrow my search down to manual transmission TDIs and see what I can turn up.

Thank you, everybody!

 

[Matt-98AHU]

I've heard from a few people, one being a vendor, that the 6 spd isn't as strong as the 5 spd, and getting the starters are a little more unique. Both are good options, but must be from a tdi.

6 speed is definitely stronger than the 5 speed, especially for higher powered cars.

But it has more frequent reliability issues with clutch hydraulics and selector arms inside the transmission. But the gear stacks themselves can absolutely take a lot more torque than the 5 speed without stripping out a gear.

 

[Nero Morg]

Well due to that, I'm sold on keeping my 5 speed then!

 

[benmarks]

Side note re 02M selector arms, there's a point where VW switched to all-steel. You can also buy the OEM parts and install them. I'm less aware of the hydraulics issue.

Re gearbox codes, Google for 02J or 02M and "workshop manual" and you should find some pretty useful charts.

 

[Matt-98AHU]

Side note re 02M selector arms, there's a point where VW switched to all-steel. You can also buy the OEM parts and install them. I'm less aware of the hydraulics issue.

Re gearbox codes, Google for 02J or 02M and "workshop manual" and you should find some pretty useful charts.

Correct, there are upgrade parts, although the ends of the selector where they engage the selector collar are plastic... But, so long as you don't rest your hand on the lever while driving, they should last a reasonable amount of time.

Slave cylinders are known for occasionally going out on the 6 speeds, and of course those require transmission removal to replace (integrated with the throwout bearing).

Figures that the 5 speed, which has the slave cylinder on top of the transmission and on the outside, easily replaceable, is also more reliable...

 

[benmarks]

You can also get brass sliders to replace the plastic ones too. Places like Darkside that sell the shifter fork kits also sell the sliders.

 

[Nuje]

On a side note to this , I’ve kept my auto axles and just replaced the 100mm flanges with 108mm….took all of ten minutes when I did my swap.

Where did you get the flanges? I thought I could use the flanges off the 01M, but upon removal of them....not gonna happen.
And looking online locally (CL or FB) people want you to take the whole transmission (and commensurate $$) along with the flanges.

 

[Nuje]

Perfect. I was expecting the gas parts car to require something like a different computer or other electric items, but I was most worried about simple and non-obvious mechanical ones.

You don't really need a parts car because the manual transmission is pretty "dumb" - just a collection of steel gears inside an aluminum housing.
Parts list:

• Used out of car:
  • Transmission (of course)
  • Clutch pedal (and optionally brake pedal - you can keep the wide automatic brake pedal, too, or chop it down)
  • Clutch slave cylinder and hydraulic line
  • Axles (as noted above, flanges on the 02J are different from the 01M)
  • Starter
  • Shifter cables / box
• Recommend buying new:
  • Clutch kit: LUK 17-050 is probably the most economical; if you're looking to do some power mods in the future, then look at a G60/VR6 clutch kit - idparts.com or CascadeGerman.com have good options there.
  • Clutch Master cylinder (Sachs or Febi-Bilstein)

I can typically get all of the above used parts as a swap kit for around $600CAD. Clutch kit: $300-$400 or so. Master Cylinder: ~$50

 

[benmarks]

When performing a swap like this, I recommend testing the shifter for slop and overall feel. If it's not very firm, look into DieselGeek or other places that may sell replacement bushing kits. It's a million times easier to do this now while everything is out of the car. This includes some of the parts on the transmission housing too. There's a plastic slider that can wear out, and the plastic connectors on the gearbox end of the shifter cables can wear out too. DieselGeek sells everything you'd need. Having a like-new shifter can make the overall experience much better.

 

[boertje]

And darkside will pre-install a set of forks in the 02M that have been beefed up Should you want that. Thats what i did with the last kit i ordered.

 

[Hyde7278]

I have 2 5spd full swaps that will be for sale soon. One is in the car I will be putting a 6 spd swap in and the other is in a car that is rotting away. Also will have a New Southbend stage 2 endurance clutch and flywheel for sale and a new VW .658 5th gear set for sale also.

 

[burn_your_money]

Most of the gas transmissions use a 0.84 5th gear. The TDI a 0.76 (rounding up to the nearest hundredth).

To top it off, you also have wildly varied final drives:

4.24 final drive for most of the 2.0 8V transmissions
3.94 final drive for early 150 hp 1.8 turbos
3.64 final drive for later 180 hp 1.8 turbos
3.39 final drive for the TDIs...

At 70 MPH it appears that each final drive increases the RPM by ~200 assuming you swap A 5th gear from the tdi to the gasser tranny. That doesn’t sound too miserable, but maybe the 4th to 5th jump is miserable?

Can the 5th gear easily be swapped around on these Transmissions? Can the 108mm axles be swapped to the donor car?

 

[benmarks]

And darkside will pre-install a set of forks in the 02M that have been beefed up Should you want that. Thats what i did with the last kit i ordered.

And, if you're doing an auto-to-manual swap, there's a checkbox to add all the extra parts for that too.

 

[benmarks]

At 70 MPH it appears that each final drive increases the RPM by ~200 assuming you swap A 5th gear from the tdi to the gasser tranny. That doesn’t sound too miserable, but maybe the 4th to 5th jump is miserable?

Can the 5th gear easily be swapped around on these Transmissions? Can the 108mm axles be swapped to the donor car?

I don't know about the flanges, but there's a lot of info here about swapping the 5th gear.

 

[burn_your_money]

I don't know about the flanges, but there's a lot of info here about swapping the 5th gear.

I guess what I’m asking is if the 2.0 and both 1.8t transmissions are 02J and if all use the same sized shafts making 5th gear interchangeable. I’m assuming yes.

 

[Matt-98AHU]

At 70 MPH it appears that each final drive increases the RPM by ~200 assuming you swap A 5th gear from the tdi to the gasser tranny. That doesn’t sound too miserable, but maybe the 4th to 5th jump is miserable?

Can the 5th gear easily be swapped around on these Transmissions? Can the 108mm axles be swapped to the donor car?

I've swapped a TDI 5th into a 2.0 gas transmission before. It knocked it down to 3500 RPM instead of 4000.

But, it's a lot closer if you're using a later 1.8T transmission with the 3.64 final drive. And there are taller-than-stock TDI 5th gears available. So, you could conceivably swap a 0.658 into an EHA code 1.8T 02J transmission and be about right. There will be a substantial gap from 4th to 5th, which may require not only rev-matching, but double clutching to go from 5th back down into 4th while rolling to not exert excessive force on the selector. Heck, I have to do that as it is on my stock TDI transmission with a 0.658 5th...

Math: 3.64*0.658 = 2.395
Stock TDI box: 3.39*0.756 = 2.56

So, you'd actually have a taller total gear reduction in 5th with a 0.658 on a later 1.8T 180 hp transmission. There are other options out there as well, 0.717 5th would make it just a tiny hair shorter total reduction in 5th compared with the stock TDI transmission, but it's so very close that it may only be about a 50 RPM difference, if that.

I would stay away from the super short final drive 2.0L transmissions, but a later 1.8T with the 3.64 final drive (would have to be 2002 model year or newer) is a lot easier to make it work well for a TDI if you also get a taller-than-a-stock-TDI 5th gear.

5th gear swaps are doable with the transmission still bolted to the car. You will want a relatively small 3 jaw puller with jaws small enough to fit into the synchro gaps of the selector hub. Then also a small 2 jaw to get the output 5th gear out. Plenty of documentation available here.

Axle flanges are easy, they're held in by a 6 mm allen bolt in the center.

 

[burn_your_money]

I’ve recently done a 5th gear swap on a 02A. I’m not a big fan of the 4th to 5th RPM difference but it’s livable.

Regarding the axles, can I simply keep the 108mm axles and flanges? If I’m buying a whole parts car I’ll have them anyways, where I won’t have 100mm flanges or axles.

I’m not the OP, just someone in a similar situation.

 

[Nuje]

The flanges out of the 01M are incompatible with the 02J transmission.
02J on the left; what I pulled out of 01M on the right.

 

[PakProtector]

There is enough PITA factor for a first time builder to just get the right bits in the first place. As in, a TDI trans...if possible an EUH from a PD car with its .744 5th...but it is hardly worth turning down a good EGR box with tis .756...

Put in a good clutch, bearing, pivot ball and if need be, clutch fork. I do not like the idea of splitting engine and trans to fix a cost save bit later.

Douglas

 

[dave_k03]

There is enough PITA factor for a first time builder to just get the right bits in the first place. As in, a TDI trans...if possible an EUH from a PD car with its .744 5th...but it is hardly worth turning down a good EGR box with tis .756...

Put in a good clutch, bearing, pivot ball and if need be, clutch fork. I do not like the idea of splitting engine and trans to fix a cost save bit later.

Douglas

I'm looking to put an EUH in my 02 ALH Car. Have you done it? I've read some issues about the speed sensor being a problem?

 

[PakProtector]

I have seen no difference in the connectors on my EUH and EGR. My '02 is running an EGR, so to answer your question, no I have not done it.
cheers,
Douglas

 

[dave_k03]

I have seen no difference in the connectors on my EUH and EGR. My '02 is running an EGR, so to answer your question, no I have not done it.
cheers,
Douglas

Awesome, well that's good information to know. I just didn't want to do it if they weren't compatible. Thank you

 

[Nuje]

I just put an 02J out of a BEW into a 2002 Golf and the connectors fit the speed sensor just fine.
(And if the connector didn't fit - you could find out what the proper connector is and get one from wrecker or dealer for <$5 probably, and with a pin-removal tool, swap the wires over in a couple minutes; I've had to do that with 2003 injectors going into that same 2002 car - no biggie).

 

[vandermic07]

I've swapped a TDI 5th into a 2.0 gas transmission before. It knocked it down to 3500 RPM instead of 4000.

But, it's a lot closer if you're using a later 1.8T transmission with the 3.64 final drive. And there are taller-than-stock TDI 5th gears available. So, you could conceivably swap a 0.658 into an EHA code 1.8T 02J transmission and be about right. There will be a substantial gap from 4th to 5th, which may require not only rev-matching, but double clutching to go from 5th back down into 4th while rolling to not exert excessive force on the selector. Heck, I have to do that as it is on my stock TDI transmission with a 0.658 5th...

Math: 3.64*0.658 = 2.395
Stock TDI box: 3.39*0.756 = 2.56

So, you'd actually have a taller total gear reduction in 5th with a 0.658 on a later 1.8T 180 hp transmission. There are other options out there as well, 0.717 5th would make it just a tiny hair shorter total reduction in 5th compared with the stock TDI transmission, but it's so very close that it may only be about a 50 RPM difference, if that.

I would stay away from the super short final drive 2.0L transmissions, but a later 1.8T with the 3.64 final drive (would have to be 2002 model year or newer) is a lot easier to make it work well for a TDI if you also get a taller-than-a-stock-TDI 5th gear.

5th gear swaps are doable with the transmission still bolted to the car. You will want a relatively small 3 jaw puller with jaws small enough to fit into the synchro gaps of the selector hub. Then also a small 2 jaw to get the output 5th gear out. Plenty of documentation available here.

Axle flanges are easy, they're held in by a 6 mm allen bolt in the center.

Just so i understand, Are you only swapping the 5th gear set out of the 1.8T trans or are you swapping the whole trans? If whole trans, what is 1-4 gearing like?
I've often wondered if there would be any way to make 1st a little slow @ idle speed? its hard on the clutch when crawling around on some back roads @ less than 5 MPH. It would also make takeoffs when towing nicer.

 

[MaverickH1]

Just as an update... miraculously... the filter and fluid change seems to have eventually fixed everything in the automatic transmission 1,000 miles later.

So hopefully it'll last awhile before I have to make the swap!