Tranny and speedo issues on 96 TD

[addautomotive]

Howdy all...
Just bought a 96 1.9 TD jetta... absolutely love it but came with a couple known issues:

1) When in reverse, the transmisson makes a bad clicking noise. Sounds expensive.
2) speedometer/odometer work intermitently. Is this a common problem? if so, is it generally the speedometer itself that is at fault, or the sender in the transmission?

other than that the car is awesome... rust free, well maintained. New  brakes, exhaust tires and struts. Ac and cruise. Best of all, the dreaded carnk bolt issues have already been taken care of.

[QuickTD]

The clicking in reverse is common. The reverse idler gear in these trannys is a bit fragile. The gear teeth can become chipped/broken resulting in the noise you are hearing. Be gentle with it and it may last a long time. The only alternative is disassembly of the transaxle and replacement of the gears. A junkyard tranny (or the reverse gears from one) may be less expensive. The good news is that the 5 speed 020 tranny is essentially unchanged since the rabbit. It can be a bit hard to find one with taller diesel ratios though.

Since neither the speedo nor the odo work, the problem is likely the sensor in the transaxle. It may have a bad connection, the magnetic tip may be covered with metal "trash" (perhaps reverse gear tooth fragments?) or it may be electrically faulty. It can be removed and inspected quite easily. It is located at the rear of the trans, just ahead of where the drivers side axle shaft exits the tranny case. One bolt and a retainer hold it in. Be sure to clean the area around it before removing it, gravel tends to collect there. You don't want that stuff falling into the tranny when you pull the sensor.

[addautomotive]

Thanks for the response. I was told to drive it gently and it should be good for a while...

More questions...

1)Are the reverse idlers weak on the A3's only? I've never heard of this issue on the A1/A2's. I wonder how hard it would be to change the reverse idler... anyone done this before?  I'm not afarid to take it out and apart.

2) Are there gear charts available for the later cars? I've seen them for A2's but not sure if they cover A3's. I believe my trany code is ACH but that's from memory... I'll double check later. The reason I ask is that I'd like to do a 5th gear (0.71) swap, but would like to know what kind of a change I can expect. I'm currently running approx 3000 rpm's at 120 km/hr. (speedo works occasionally). I've done the swap in my 87 and really noticed a difference.

3) Is it possible to swap in my 87 tranny? I'd prefer not to do this, as it has weak 1-2 synchros. However, if I lose reverse altogether, I may have to do this in the interem. How would the speedo work then? my 87 uses a cable... does the newer style bolt right in?

and finally...

4) I think I should probably drain the tranny oil... if the problem is a chipped/broken reverse idler I probably have chunks of whatsits that ought not be splashing about. What type of gear oil do I put back in? I'm looking for brand, and looking for someone who has used it succesfully in the canadian climate. I can't remember what I put in my mother's 92 jetta, but it is horrible in the winter now... very difficult to shift.

[QuickTD]

1. The reverse gears are generally a bit tender in all 020 trannys A1,A2 and A3. They will not tolerate the reverse gear donuts or burnouts that other trannys will. The heavier A3 body doesn't help. The reverse gears are also non-synchronized and often get chipped just from shifting to reverse without waiting for the mainshaft to stop spinning.

2. The A3 bentley contains a gear chart. The factory fifth gear is 0.75. I installed a 0.71 gearset and I get about a 200rpm drop at 120km/h. Mine runs exactly 3000rpm @120km/h, it used to run 3200rpm.  It makes for a quieter ride but it would take 100 years to make it up in fuel economy.

3. The 87 tranny will fit if it has 100mm CV flanges. The speed sensor may not work. I don't think the A3 trannys use a gear to drive the sensor, they just have a reluctor wheel on the pinion shaft. I could be wrong though.

4. The reverse gear chips will be stuck to the magnet in the bottom of the tranny, thats why its there. They probably won't come out with the oil and doubtful they cause much harm. The genuine VW G50 oil is good but at ~$20-30 a litre its a bit spendy. I've tried redline MT-90 and don't recommend it for the Canadian climate. Redline MTL is a bit thinner and would be a better choice. I am currently using Canadian tire store brand full synthetic gear oil. I find it shifts better than the MT-90, though I haven't tried it in the severe cold (-20ºC) yet. It isn't a GL-4 product so it might be corroding my synchro's as we speak, but for the money and the performance, I'll take my chances...

[addautomotive]

%^&% So then the tranny will eventually have to come out. I'll change the gear oil, and wait for it to fail. When it does I'll swap the 5th and change the reverse idler.

Anyone have any decent exploded views of the tranny so I can get a sense for what I'm up against? Anyone else ever replaced the reverse idler?

200 rpms is enough to make it worthwhile for me. I do a fair bit of highway driving. BTW I just double checked and my tranny code is ATH... is that a 0.75?

I failed to mention that the tranny makes a rough noise as I let the clutch out... kind like a fast  "shugga shugga shugga", and I can feel a vibration through the clutch pedal. I figure the TO bearing is on the way out.

[QuickTD]

As far as I know, all A3 diesels have the same 5th gear ratio. I think my 97 is ATH as well. I've got no exploded views of the tranny. The fifth gear swap instructions are available at http://www.driversfound.com/scirocco/techtips/5thgearconversion/ As far as changing the reverse gears you might try the A2 bentley manual. I think it contains some 020 tranny info. The A3 Bentley is totally useless for tranny work...

 

I failed to mention that the tranny makes a rough noise as I let the clutch out... kind like a fast "shugga shugga shugga", and I can feel a vibration through the clutch pedal. I figure the TO bearing is on the way out.

Don't waste your money on a clutch, mines been doing that for 100000km. I've replaced everything related to the clutch and the severe vibration through the pedal is still there. It got a bit better for about 30 minutes after I changed the pressure plate, disk, release bearing, release plate, pushrod, pushrod bushing and seal and the cable. If I rest my toe on the pedal when underway, just enough to take up the free play it can be felt (and heard) pretty plainly. The vibration is proportional to engine speed and gets much stronger under power. I'm wondering if its just crank flex being transmitted through the clutch linkage. It's really annoying but doesn't seem to be hurting anything...

[Wingaman]

3. The 87 tranny will fit if it has 100mm CV flanges. The speed sensor may not work. I don't think the A3 trannys use a gear to drive the sensor, they just have a reluctor wheel on the pinion shaft. I could be wrong though.

By memory, both are bolton. You can just remove the cable speedo and put the vss (electronic speedo sensor) on any 020(A1,A2,A3). I got a A3 94 1.9TD tranny ACH/ACN(never sure of the correct tranny code) in my garage, i gonna check tomorow to be sure.

[addautomotive]

QuickTD:

Re: 5th gear... funny, that's the webpage where I first learned about 5th gear swaps. Done it twice now, I'm pretty comfortable with that procedure. I'm more concerned about doing the reverse idler. I don't want to ASSUME I can handle it, on the other hand I don't want to just assume I CAN'T do it and just swap trannies.

Interesting about the clutch noise... and good info. You probably prevented me from going on a wild goose chase. I'll just live with it.

Wingaman: Thanks for the info... let me know if you confirm that the two are interchangeable.

[addautomotive]

Howdy folks,

I'm going to bring this thread back to life... my reverse finally went south today. I'd like to swap out the idler (hoping that's ALL that's broken).
I tore apart the "donor" tranny (from an 87)... but wasn't sure of the PROPER way to lift off the housing without disturbing all the shift forks. Any tips? I've posted the complete details here:

http://www.vwdiesel.net/phpBB/viewtopic.php?t=1566