VWDiesel.net The IDI, TDI, and mTDI source.

Engine Specific Info and Questions => IDI Engine => Topic started by: molgrips on October 25, 2008, 12:09:07 pm

Title: Gear ratios
Post by: molgrips on October 25, 2008, 12:09:07 pm
So I've searched the site and I've found that there are loads of transmissions and people are talking about changing individual gears or the final drive ratios...

The question is, what's the easiest way of making my gears longer on my 1994 Passat 1.9 TD?  I'm running at about 2900rpm at 70mph, which is kinda noisy.  The engine gets noisy at 2,500rpm, and there's also something resonating which makes it worse.

So it's either:

a) Get bigger wheels - I've got 14s on it now.  Can you recalibrate the speedo?
b) Replace the tranny with one from a scrap yard - only these seem to be hard to find these days
c) Replace 5th
d) Change the final drive

I'd prefer option d), but I don't know if it's possible.

Which is easiest?  I've never worked on a transmission before :)
Title: Gear ratios
Post by: Dirtrag2 on October 25, 2008, 01:10:34 pm
I think replacing 5th is the easiest... check out this link for the DYI http://www.brokevw.com/
Title: Gear ratios
Post by: jtanguay on October 25, 2008, 01:17:42 pm
put bigger tires, grab a tranny with a taller r&p and then install the .655 5th gear.  you'll be cruising 80mph @ 2500 rpm  8) but need to downshift for hills  :lol:

but yea apparently its pretty easy to replace 5th gear on these trannies.  and can be done in car!  also a good time to replace the oil.  bleached bora sells the 5th gear sets. forget his site url though.
Title: Gear ratios
Post by: molgrips on October 26, 2008, 01:40:09 am
Erk, doens't look all that easy.. but I guess it's always better when you get things out and can see them....
Title: Gear ratios
Post by: Turbinepowered on October 26, 2008, 03:24:38 am
Quote from: "jtanguay"
put bigger tires, grab a tranny with a taller r&p and then install the .655 5th gear.  you'll be cruising 80mph @ 2500 rpm  8) but need to downshift for hills  :lol:

but yea apparently its pretty easy to replace 5th gear on these trannies.  and can be done in car!  also a good time to replace the oil.  bleached bora sells the 5th gear sets. forget his site url though.


www.boraparts.com is his linked-to site, but a quick glance through didn't turn up any transmission parts like that. Granted, might be like Myke and not have everything he has in his stock listed on his site.
Title: Gear ratios
Post by: cyrus #1 on October 26, 2008, 10:26:44 am
http://www.boraparts.com/catalog/advanced_search_result.php?keywords=5th&x=61&y=6&categories_id=&inc_subcat=1&manufacturers_id=&pfrom=&pto=&dfrom=&dto=

Here's a .681 and a .658 5th.  If you're looking for ease of install, I would stay away from R&P swaps.  Excuse my ignorance but would this passat have an O2O or an O2A?
Title: Gear ratios
Post by: molgrips on October 26, 2008, 11:26:02 am
$350!  That's a bit more than I thought for a couple of cogs...!

If that's how much it costs, maybe I'll just get bigger wheels...
Title: Gear ratios
Post by: molgrips on October 26, 2008, 11:27:04 am
PS what's R&P mean?
Title: Gear ratios
Post by: cyrus #1 on October 26, 2008, 11:31:45 am
Ring & Pinion.  It's the final drive and to replace it you definitely need to crack open the trans.
Title: Gear ratios
Post by: Jettagli16v on October 26, 2008, 11:48:35 am
R&P = Ring & Pinion (AKA Final drive) the ratio with which the output shaft turns the differential (consequently the tires)

Holy cow!
I did not even know I could get a .655,
I thought I was relegated to .75 & .71, and was looking for the 3.667 Final (ACL Trans code)

Now I have a new, elusive, abstract transmission part to seek out!
Title: Gear ratios
Post by: ericgoum on October 27, 2008, 02:57:17 pm
If you go to the website http://a2resource.com/ you can see the gear ratios of all engines and can use it to figure out what you need at a junkyard. I currently have a .75 5th in my '85 Jetta and when I was at the junkyard recently found a vehicle that had a .71. Cost me 6$ for the gears and all parts relating to those gears. Should be good for a couple hundred RPM drop at the speeds you are talking. Maybe not as extreme as the others. I plan on replacing this sometime in the near future. Hope this helps.

Eric