020 transmission options for TD Jetta

[AAZJetta]

Hello, all, I'm new to this forum, it is GREAT!!!

I have a 1985 Jetta turbo-diesel I've installed an AAZ 1.9 litre TD into, and I'm running the stock ACH code 020 transmission.  The car is working fine as is, but since 95% of my driving is on the freeway, I'd like to swap in another transmission that has a higher final drive to cut down on engine RPMs at highway speeds (2900@65 mph according to dash tach and a GPS).  I was thinking maybe transmission codes ACN, AON, ASF, or ACL that have a final drive of 3.67 and a 5th gear of .75 would be optimum.  I know where I can get an AUG trans with a 3.67 final, but the 5th gear would have to be changed to a .75 or .71.  Can the AUG be upgraded to either of these? Would it be a better choice (modified as stated) to the other choices I'm considering?  I also know where I could get a 9A trans, but again, the 5th gear would have to be changed.

Somewhere else on this forum I saw something about a transmission code CHE, which I know nothing about, and have no idea where I could get one anyway.  I think this may have been one of the stock transmissions used with the AAZ on the '93-'97 Jetta in Canada, having a final ratio of 3.67 and a 5th gear of .75.

Has anyone had any experience with this situation, or could anyone shed some light on what would work best with this car? I don't know all of the intracacies of each transmission.  I'm still running the stock 185 70 R13 tires on the car.  The car is getting 44 mpg consistently at 65 mph without cruise control, which I'm installing tomorrow.  The car has plenty of power in the stock condition, but revs higher than I think it needs to at highway speeds.  I think this will improve the fuel economy as well.   Thanks!!!

P.S. As an experiment, I swapped some 185 70 R14 tires on the front and took the car on a highway run.  The tire size alone cut RPMs at 65 mph down 100 rpm, and the car still had plenty of pickup and power.

[Kudagra]

If you get a 8v transmission you want with 1st through 4th gears you want you can swap the 5th over no problem. There are plenty of people around the net that show how to do it.

www.brokevw.com is one place.

[RabbitJockey]

with these engines, especially an aaz you want the tallest gears in all gears as possible.

[AAZJetta]

Anybody have any idea where I can get .75 or .71 5th gear sets for any of the transmissions I was considering that didn't have it already?

[Kudagra]

Anybody have any idea where I can get .75 or .71 5th gear sets for any of the transmissions I was considering that didn't have it already?

This guy seems to have loads of parts..including the .71 you want. I have 2 transmissions with .75s in them but I dont think they are coming apart any time soon.

http://forums.vwvortex.com/zerothread?id=2937171

[burn_your_money]

The differance between .71 and .75 is about 200 rpm IIRC

[AAZJetta]

Can a .71 5th gear set be installed in an AON, ACL, ASF, or ACN, or just the .75?

[hillfolk'r]

i have an asf currently
im swapping the 2-5 gears in that box
from ones from a 7A
it has a .71 5th
according to broke,its a workable swap if you use a "mk2 8v trans  with a 3.67"
you could use a 16v 3.67 r+p,but then you only have 2 choices for 4 gear ratios
the asf is  a "mk2 8v box with a 3.67 r+p"

this guy is good too for info,awesome site


http://brokevw.com/