VW transmission woes... expert help needed

[notfarnow]

Hey folks,

I hate to post a non-Porsche tech question here, but I know there are quite a few VW folks in the crowd. I also know there are some pretty brave DIY'ers out there as well.

I have a 1996 VW jetta with a 1.9 turbo diesel engine. It has a later "020" transmission (code ATH) that is based on the same fwd transmissions used in vw's since about '78.

When I bought the car last year, it "clicked" when backing up. I was told the reverse idler was chipped (apparently common on these), and if I nursed it I should be able to get a couple years out of it. Part of my "nursing" routine was recently towing a trailer with 3/4 ton of gravel, and backing up my driveway, but I digress.

Today, I lost reverse completely. To be more specific, my fiancee lost reverse. She was driving, so technically it's ALL HER FAULT.

Now, I've known this was on the way, so I kept an old transmission handy and tore it apart today for its reverse idler and its nice tall 5th gear. I've had the "end cones" off these transmissions before( while they were in the car) to do 5th gear swaps and throw-out bearings, but I had never taken the whole housing off. So now I have so pretty serious surgery ahead of me, and am looking for expert advice.

My plan is to disassemble the'96 transmission and swap in the good idler.
Questions:
a)What do you think the chances are that ONLY the idler is damaged? From what I've read, this is quite common... but I've been driving it like this for a year, and who knows how long the PO did.
b)I need to know the RIGHT way to remove the housing. When I took apart the old spare tranny today, I just removed the shift rod and let the forks fall where they may. What is the proper way to do this, so that I can slide the housing up with all the forks in place? Do I put it in a certain gear, or do I need to remove the selector mechanism from the housing?

I'd really prefer to repair this transmission than purchase a new/used one... if i can fix this one myself it'll save me from having to take about $1000 from my Porsche Savings fund.

Thanks for any help,
Jake

[widebody911]

Try asking over @ http://forums.vwvortex.com

[ejm914]

Besides reverse gear the 1/2 op sleeve is usually replaced, sometimes a mainshaft is needed. Take the selector assy out by removing the threaded cap near the clutch cable support. Reach in and manually shift the tranny into two gears to lock the shafts so you can loosen the bolt in the end of 5th. Remove 5th gear but leave the rod in the shift forks in place. After removing the case you can lift the rod slightly and pull the forks off as an assembly. Be sure to remove the complete pinion shaft and check the bearings, chips from reverse often get in and destroy the small one.

[notfarnow]

Thanks Ed,

I have a homemade tool for locking the mainshaft, I use it when doing 5th gear swaps.

Before removing the case, do you usually undo the 4 bolts for the mainshaft bearing, or do you leave the mainshaft bearing on the case? The Bently manual is says to unbolt the mainshaft bearing collar, but the info I've been able to find online says I'm not likely to be able to get the bolts out without tearing them up. In The local VW shop said I could just whack it with a piece of hardwood and it should pop loose. It's pressed in, and it looks like I'll have to rig up a press to "pop" it out.

Thanks for the info about the selector assembly, that was my biggest concern.

Thom, I haven't had much luck with vwvortex in the past. It seems to be a great place to talk about 17" rims and cold air intakes, but never seems to be much good for "down and dirty" work.

[ejm914]

You don't unbolt the bearing when using the correct tool, something which could easily be duplicated. It is a steel bar approx. 1.5" X 3/4" X 6" with holes at the ends and a large threaded bolt near center. You use a couple of long bolts from the 5th gear housing to hold the bar down, the center bolt is tightened against the end of the mainshaft to pull the case off. It take a bit of pressure, you want the bolts deep in the case so they don't strip and be careful not to damage the threads in the end of the mainshaft. Be sure to remove the bolt on the bottom that supports the reverse idler shaft, speedo gear and b/u light switch before pulling the case.

The local VW shop said I could just whack it with a piece of hardwood

[notfarnow]

Yeah , the local VW shop can be a bit rough, but they were nice enough to loan me their Bentley manual. It shows the same bar that you describe.

Thanks again Ed!