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How-To: 020 Transmission tear down.Transmission tear down.
Stripping the 020
This page will show the basic steps of opening the 020. The page is mostly for reference to be used in addition to the Bentley manual or another suitable copy of rebuild procedure for the 020.
Because of the variations between the various codes used for the 020, not all of the pictures will match what you might find inside your trans.
This page will cover opening the trans after the flanges and 5th gears are removed. To get those parts off, follow these links to the pages showing that procedure.
5th removal
Flange removal
OK, start by draining the trans of any and as much oil as you can. You won't get it all out, but get what you can removed. Once it is drained, the trans can be mounted to a stand to begin work.
Remove the pushrod by pulling it out and notice that one end of the pushrod is perfectly rounded, while the other end is slightly tapered before being rounded. This smaller tapered end should contact the thrust release plate, and the perfectly round end should fit the TO bearing.
If you flip the rod, the smaller end won't fit properly into the TO bearing, and won't distribute the load across the entire bearing cup, and the TO bearing can fail. Aftermarket pushrods generally do not have a tapered end as the factory rods do (recently I have ordered aftermarket rods, and one end was tapered like OEM, so that statement doesn't ring as true as it once did). Both styles will have blued ends, and this is not a fault, this is just the result of the factory heat treatment to harden the end of the rods.
The tapered end to the thrust plate....
The rounded end to the TO bearing...
OK, dig all of the grease out of the flange, and follow this link to remove the flanges...
After you remove the 5th gears and end case as shown on this page you should be looking at the trans as shown....
Use a GOOD quality driver to remove the 4 bolts that secure the large bearing clamping plate inside. These bolts are easily stripped, and usually in there VERY tight. If you notice in the pic above, the 2 bolts to the left have been cleaned of any fluid in the head, and the 2 on the right are still full of fluid.
If you do not remove the fluid, the bit will try to compress the fluid in the bolt as it is inserted, and as proven with the hydraulic braking system, fluids do not like to compress. The result is the driver won't fit fully into the bolt, and it'll round the bolt out.
The bolts are XZN bolts (also called triple-sqaure or 12-point) in 6mm size.
Remove the reverse bolt that secures the reverse idler shaft inside the trans (the shiny round hole in the middle of the case in the pic below), and remove the case bolts around the case edge.
The case bolts are all 13mm, and the reverse bolt could be a 13mm or a T-47 Torx bolt.
Now is the time to install the input shaft support bar. This allows the force of the pressing operation to follow to not be transmitted to anywhere but through the shaft and into the support arm.
This pic was stolen from the rebuild portion, because for some reason I managed to lose the pic showing the support being used on the dirty trans. Install it as shown, then tighten the center bolt up until it just supports the weight of the input shaft. VW calls for the VW295A adapter to be used between the bolt head and the input shaft end, but as long as it is a good solid support and not damaging the shaft, it'll work fine.
Install a case splitter tool as shown, threading the 13mm bolts into the holes for the end cover, and aligning the screw over the input shaft. Tighten the case splitter until the case splits and the main ball bearing will stay on the shaft.
Now you can lift the gearbox off of the bellhousing, exposing the input and output shafts....
Here you can see the magnet covered in metal, and chunks of teeth, and a couple missing teeth from the ring gear.
OK, the case has been opened and the shafts exposed, next is to remove the shafts from the case....
OK, the shafts are ready to be removed, start by lifting the shift forks and rod out of the box, wiggle the rod up a bit, to allow the bottom of the forks to swing away from the gear stacks, and lift the entire assembly out...
Now, the input shaft can't be lifted out until the 4th gear is removed the the output shaft. Use a pair of decent circlip pliers to remove the circlip that secures 4th gear to the output shaft...
Here you can see when the 4th gear is removed, the input shaft can be lifted out as a complete assembly. You have to lift the input shaft and 4th from the output shaft at the same time, this pic is only because I needed one hand for the camera....
On 16V and 2.0L trans (up to date code 01067) the 4th gear will have an additional circlip under it. This DFQ is an August '97 trans, so they have stopped using the larger 4th gear wheel, and it is like the MK2 8V trans.
Remove the circlip that secures 3rd gear...
Pull out the reverse idler gear and shaft, the bolt can be used to help removal. Twisting it as you pull up can help it come loose...
Use a puller with 250mm arms to reach down and grab the 1st gear. You will pull 1st gear, the 1st/2nd sync hub and collar, 2nd gear, 2nd gear needle bearing race, and 3rd gear off in one go.
The hooks will fit into a small cut on the output shaft bearing clamping plate to get under 1st gear...
You are now left with the bare output shaft, and the 13mm bolts that hold the clamping plate on can be removed and the output shaft and both bearings can be lifted out...
Bearing rollers ideally will be in the bearing, this is a bad sign :)...
The shafts are out, now the diff can be lifted free and the shafts stripped bare.
With the shafts out of the way, the differential can now be lifted out of the case....
You can see the damage on the inside of the case in places from the metal being spun around inside by the ring gear, and you can see the very silver colored oil...
Remove the input shaft ball bearing using a bearing splitter as shown...
You can now lift off 4th gear and the synchronizer ring to expose the large circlip that holds the 3rd/4th sync hub onto the input shaft...
Remove the circlip, it is fairly large and stiff, so it can be tricky to get a good grip on...
With the circlip removed, you can now press 3rd gear, and the 3rd/4th sync hub and collar from the shaft. The plate shown is VW402 and has a round section with a lip that 3rd gear fits into...
Here is the 3rd gear needle bearing, it is split, and needs spread open to be lifted up and off of the shaft. I've got the shaft mounted in a vise with soft jaw inserts so I could hold the bearing open and take the pic...
That leaves the input shaft stripped and bare, and the output shaft has only the taper bearings pressed onto it.
Use a bearing splitter as shown to remove the taper bearings from the output shaft...
To remove the diff bearings, you can use a bearing splitter as shown with the output shaft bearings above, or the VAG1582 bearing puller can be used.
The end clamps over all of the rollers at once, and locks itself onto the bearing without damaging the bearing or cage....
Here you find the cause of all the damage we've seen so far. One missing rivet head. The head then was spun around and started destroying things. Often times the rivet or broken piece of gear get spit through the case or are spun around until several holes are machined around the diff area from the inside out. This is commonly called SMS or Self Machining Syndrome.
The small rivets can fail as shown, or the cross shaft, which is secured with clips on this example, could also cause the large-head rivet on each side of the shaft to be damaged from the shaft smacking into it. When the large-head rivet is gone, the rivet head can do the same damage as shown here, but the shaft can float out and knock a hole in the case as well.
Some trans have rivets only, some have rivets and circlips on the shaft, some shafts are secured with a roll pin, but they all use rivets, and can fail as shown here.
I'm not covering the tear down of the differential just yet, when I get the pics for it, I'll update this page or make another.
The case halves can now be stripped of their bearings and races.
The case can now be stripped of the races and bearings that remain.
Remove the gearbox output shaft roller bearing as shown...
The bellhousing has the input shaft roller bearing, and it is pulled using an internal extractor. If you do not have an internal extractor, then the bearing can be pressed out from the other side. Remove the filtering screen plate from the case before attaching the puller support...
The internal extractor opens up as shown to grab the bearing...
Pull the output shaft small bearing outer race from the bellhousing as shown here...
Make sure that the pulling hooks of the internal extractor are in this position, so they are able to fit under the bearing race...
There is a small section in the bottom of the bore that the race sits on, this is higher than the bottom of the bore, allowing the extractor hooks to grab....
The diff carrier bearing races are pressed out of the case the same way basically, this shows the gear box side being removed, VW554 fits into the hole and just catches the race...
I'll add more pics later of the seals being removed and the green seal sleeve and 5th end cap being removed, but they basically pry out and are replaced with new.
The trans should now be stripped for most repairs that you would want to do.
Write up courtesy of Brian, of BrokeVW.com
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