Gear Box Selection

[silentdub]

http://www.mk1dubz.com/forums/showthread.php?t=370

Looking at the different codes, I have a few gear boxes to choose from.

I am wondering how much the final drive ratio will differ between say the 3.94 & 3.67?

I have an ACH with the .75 5th, but I can remove that one and put that in to a box with a final drive of 3.67


If driving in 5th at 55, how much of a drop in the RPM's are we talking about here? What are you guys running?

[rallydiesel]

I have a 3.67 and a .71 5th and like it a lot. Running a .75 5th will be almost identical and not really worth the effort of swapping unless you are doing trans work anyways.

[R.O.R-2.0]

i turn 2300 @ 60 w/ 3.67s and .75 5th..

and would be turning ~2500 with 3.94s and everything else the same.

[silentdub]

Great! Thanks guys!

I'll probably go with the 3.67 and swap over the .75 5th then.

200 rpm is quite a bit of difference.


I have the ACH with the .75, but I have several other gear boxes that I can choose from with much less mileage.

[R.O.R-2.0]

find a gasser 85-87 econo box jetta or golf.. they came with ACN trannies.. there already 3.67 & .75

ive come up with 2 of them quite easily. i love these trannies.

[silentdub]

find a gasser 85-87 econo box jetta or golf.. they came with ACN trannies.. there already 3.67 & .75

ive come up with 2 of them quite easily. i love these trannies.

True, but I will kick myself while out looking knowing that I have 4 or 5 gear boxes in my garage now, one of which has about 70K miles and is in perfect condition. The smarter thing to do may be to just swap the 5th.

Good advice either way though.

[R.O.R-2.0]

i have a basically brand new AUG trans in my shop.. it shifts better than any tranny ive seen. and is SILENT. i mean silent. but it doesnt make it any good for anything. a good 5th gear in that trans and it would be a LONG LEAP from 4th (1.13) to 5th (.75)

it might be kinda cool having gears 1-4 really close together tho..

[8v-of-fury]

i have a basically brand new AUG trans in my shop.. it shifts better than any tranny ive seen. and is SILENT. i mean silent. but it doesnt make it any good for anything. a good 5th gear in that trans and it would be a LONG LEAP from 4th (1.13) to 5th (.75)

it might be kinda cool having gears 1-4 really close together tho..

It really depends on the vehicle it is going in and what engine setup they are running.. REALLY depends.

I would not suggest a non-close ratio trans (so a far ratio?) to anyone without a turbo diesel. Your either screaming the lower gear, or lugging the higher gear.. stttuuppid gearing for an n/a motor thats for sure. It did fine behind my 1.7 gasser, and does fine behind my bro's stock TD.. but the n/a is just a dog.. an n/a really needs a close ratio with a tall 5th in it.

Soo.. what car are you driving and what engine does it have?

[vanagonturbo]

if you to scirocco.org and click on the gears, it has a list of various trannies and speed/rpm calcluator.

In my scirocco I have a 3.94 and .71 5th its about 3k at 70mph

In the GTD I have a 3.67 and .71 and its abot 2300 at 70mph. It is a little doggy compared to the scirocco, but the engine setups are not very similar either.

[silentdub]

This is a sippster project. I drive 100% highway.

I have an AUG trans and an ACH.


The AUG has a 3.67 Final Drive while the ACH has a .75 5th.

I also have a 9A with a blown diff but that has a .71 in 5th.


So at this point, I plan to run the AUG with the .71 5th. This should be good 

[R.O.R-2.0]

This is a sippster project. I drive 100% highway.

I have an AUG trans and an ACH.


The AUG has a 3.67 Final Drive while the ACH has a .75 5th.

I also have a 9A with a blown diff but that has a .71 in 5th.


So at this point, I plan to run the AUG with the .71 5th. This should be good 

aug got a .89 5th gear, and 3.67 final

ach got a .75 5th and 3.94 final

9A got a .89 5th also, and 3.67s

so, are all your trannies mixed and matched?

[rabbitman]

I have a FN in my NA bunny, the first 4 gears are spaced pretty good for acceleration and then 5th is about 700rpm away from 4th. Works ok unless you want to not loose speed on hills and so downshift sooner then it revs higher than I like.

I let it bog down to 2100-2250rpm (not pushing it very hard) and downshifting to 4th put it just under 3000rpm.

I won't complain, my summer mileage has ranged from 46-53mpg and I run the tank down almost empty for accuracy. My best tank ever was a few weeks ago and I hit 580 miles and put in something like 10.8 gallons or something. It's fun telling people about it just to watch there face as they try not to bash my "ugly slow old car" just to save their pride in driving a gas hog.

[silentdub]

I have a FN in my NA bunny, the first 4 gears are spaced pretty good for acceleration and then 5th is about 700rpm away from 4th. Works ok unless you want to not loose speed on hills and so downshift sooner then it revs higher than I like.

I let it bog down to 2100-2250rpm (not pushing it very hard) and downshifting to 4th put it just under 3000rpm.

I won't complain, my summer mileage has ranged from 46-53mpg and I run the tank down almost empty for accuracy. My best tank ever was a few weeks ago and I hit 580 miles and put in something like 10.8 gallons or something. It's fun telling people about it just to watch there face as they try not to bash my "ugly slow old car" just to save their pride in driving a gas hog.

I feel ya. I was just talking to a friend who left his new jetta at my house parked behind my jetta. I asked if he wanted to trade, he laughed. I said, yeah, you're right, mine gets better mileage. I thought he was going to cry.

[silentdub]

aug got a .89 5th gear, and 3.67 final

ach got a .75 5th and 3.94 final

9A got a .89 5th also, and 3.67s

so, are all your trannies mixed and matched?

The 9A has a .71 installed, so yes, that was modified, if that is damaged since the diff is blown up, then I will take the .75. I am planning to install the 5th gear in to the AUG since I know the AUG only has about 70K miles on it and is in excellent condition.

[R.O.R-2.0]

i hope theres gonna be a turbo engine in front of that trans?

the jump from 4th to 5th gear is going to be huge..