Changing 4th gear?

[bbob203]

the fifth gear swap is a very popular upgrade or a new trans with a taller in fifth. has anyone ever switched out 4th? I'm thinking about putting a.  .91 fourth into an a s f and then a.   .71 fidth for a custom gear box. has anyone does any of this do you think ill notice much of a difference by. changing 4th to that benefit? detremint?

[Dakotakid]

If I recall properly, an AGS diesel trans has a 4th gear which is 0.97 already (but, not with 3.67 final like the ASF). I know that a person can tell the difference between the AGS 4th gear and an ACH 4th gear with a normally aspirated car application, because I drive two of these back-to-back.

If you go this route, I hope you have enough power (TD application, right?) to make it comfortably happen. You sure might. I would not do it with an n/a diesel. You would be screaming and beating on the dash while waiting to get up to speed. That would be a mighty big step between 3rd and 4th.

Turbo lag could play into the results here as well. Something to think about.

[theman53]

http://www.scirocco.org/gears/
^just in case

IMHO definately not worth it. Swapping 4th isn't as easy as swapping 5th. I have an AGS with a 3.67 ring and pinion gears. It has the .91 4th and the .75 5th. I had plenty of power and to me it seemed as 4th and 5th were too close. I would honestly like a direct 1:1 forth gear, but since they don't have it I think your 1.03 is the best bet. I also think the gap between my AGS 3rd and 4th is a bit much, so if you were to go even higher the gap maybe too much for you. Check out brokevw's page on the teardown. You will have to split it and pull the entire shaft out.

My dream ratios would be the only option for 1st, 2nd =2.12, 3rd=1.29, 4th=1.03, 5th= .71 with the 3.67 ring. The only ratio I haven't actually driven was the 1.03 4th grear. All the rest I have tested and really liked.

[R.O.R-2.0]

http://www.scirocco.org/gears/
^just in case

IMHO definately not worth it. Swapping 4th isn't as easy as swapping 5th. I have an AGS with a 3.67 ring and pinion gears. It has the .91 4th and the .75 5th. I had plenty of power and to me it seemed as 4th and 5th were too close. I would honestly like a direct 1:1 forth gear, but since they don't have it I think your 1.03 is the best bet. I also think the gap between my AGS 3rd and 4th is a bit much, so if you were to go even higher the gap maybe too much for you. Check out brokevw's page on the teardown. You will have to split it and pull the entire shaft out.

My dream ratios would be the only option for 1st, 2nd =2.12, 3rd=1.29, 4th=1.03, 5th= .71 with the 3.67 ring. The only ratio I haven't actually driven was the 1.03 4th grear. All the rest I have tested and really liked.

the BEST OEM trans is of the ACN series..

ASF, AON, ACN, ACL (8v)    3.67    3.45    1.94    1.37    1.03    0.75

i dont like 2.12 2nd gear.. its too close.

the 1.37 3rd is nice too. and 1.03 is just a bit TOO LOW for my tastes. i think a .91 4th would be amazing. because the ACN works out PERFECT for a gasser. pull hills in 4th at any speed. 4000 revs @ 70mph up hills with the gasser.

diesel should be able to pull 5th up hills with decent power.

[theman53]

To each his own. I think you are correct in saying that the ACN group is best *stock* without messing with it.

I just liked the way the 2.12 pulled quick, I don't think you would be on boost as hard in 2nd and it would make a nicer transition, hard to tell without making one. I like the way it is on paper. The 1.29 3rd was hands down the best gear in any trans I have driven, but then like I said the .91 4th seemed a bit far away and really more like an overdrive than 4th. I just think if you go to the .71 5th the 1.03 would work better for the 4th.

Really this is all relative as if I were to drive freeway all the time then I bet the .91 4th would be what I would want. Seeing that there is not a freeway within 30 minutes of my house...probably further for a real good road that isn't 55mph in the 2 lane... I don't want it. It is good for pull, but passing not really on the terrain around here.

[R.O.R-2.0]

im not going to waste anymore time on 020 trannies tho.. as soon as i find one for a reasonable price, im gonna buy a 02A trans, and swap that in. im tired of ripping the bearings out of 020 transmixers..

020s are disposable behind a high powered diesel.. i get 10-20k miles per trans.. they all die of the same issue, VERY noisy bearings.. they dont actually die, i just get cold feet, and replace them with a noise-free box.

Lucas, ditch the 020.. your gonna have more power than before. the trans is going to be the weak link eventually....

i know, you HAD an 02A once, but someone stole it..

[theman53]

02a is on the way...if you have broke vw do an 020 for you they are 50% better than factory new. I am riding out my AGS and will swap the 02a eventually, I bought another one and some AHU cylinder head parts that should be here in Sept.

[bbob203]

If I recall properly, an AGS diesel trans has a 4th gear which is 0.97 already (but, not with 3.67 final like the ASF). I know that a person can tell the difference between the AGS 4th gear and an ACH 4th gear with a normally aspirated car application, because I drive two of these back-to-back.

If you go this route, I hope you have enough power (TD application, right?) to make it comfortably happen. You sure might. I would not do it with an n/a diesel. You would be screaming and beating on the dash while waiting to get up to speed. That would be a mighty big step between 3rd and 4th.

Turbo lag could play into the results here as well. Something to think about.

Ill be running a k14 with a td pump gov modded.

I guess ill run it as is and if the 4 doesn't cut it on the hills ill change it out. there is an asf at the local pull a part I might go snag as a spare for 60 bucks.

[Dakotakid]

At 60 dollars, I would certainly go retrieve the other trans. Generally, if the gear lube which comes out of one looks very nice, it will probably be without problems. It might be a little dark if it was not changed much (or at all.....gulp). But, if the gear lube still smells like gear lube should smell like, it is probably a good trans. So much of life is a roll of dice in so many ways.

I personally do no like the 0.91 4th much of the time as I have it in an n/a at various higher elevations with LOTS of hills in mountainous terrain. No one ever makes the mistake of saying I "haul anus" with that ratio as 4th gear!

I really like the ACN (asf) series trans and their ratios. For the vast majority of the time....everything is just right. I think you will be pleased as is.

Eventually, I will pull the annoying as heell close ratio trans in my 16 valve and install an ACN. It'll still have enough steam to skip some of the gears a lot of the time. But will need to install a bolt kit.

[8v-of-fury]

I have the ACN and its not wide geared enough for my M-TDI. :S

I can easily start in 2nd, shift to 4th and then 5th all before 60km/h.. or 1st if Im on a hill, then 3rd and then 5th. again all before 60km/h.

I always coast around town in 5th gear at 55-65 km/h. At 1250-1475rpm respectively. SUPER fuel miser.