Gear Ratio's

[Matteo]

Hi Volks,

My 90 Jetta Diesel Trans blew 5th.

I have found an 85 Jetta Diesel donor car.

90 Ratio's are: 3.45 1st, 1.94 2nd, 1.44 3rd, 1.13 4rth, .89 5th, 3.94 Final

85 Ratio's are: 3.45 1st, 1.94 2nd, 1.37 3rd, 1.03 4rth, .75 5th, 3.94 Final

All things being equal, (tire and rim sizes)

Does this mean the 85 will rev higher in 3, 4, 5th gears?

Will the 85 transmission bolt right up to my 90 Jetta GL?

Anything I need to know about before I do the swap? I have never swapped out a FWD transmission, but it looks pretty straightforward.

Any way to test the 85 trans, if the car is not running? Things to look for?

Thanks,

Matt

[zukgod1]

Go here.

http://www.scirocco.org/gears/

[zukgod1]

Yes it will bolt in IF it has the same mounts.

What's the code on the 85?

[blkboostedtruck]

you will get better fuel milage with the 85 tranny!
Duane

[Quantum TD]

you will get better fuel milage with the 85 tranny!
Duane

X2!

Sounds like you got the dreaded AXY trans that came in the 1990-1992 1.6NA cars. That trans is ***. Basically, it's the same gearing as a 1983-84 GTI. Horrid!

The 1985 has PERFECT gearing for your car. The code on the 1985 (it would have to be off a diesel car) should be AOP, AGS, ACH, or 4S. If so, scoop it up ASAP. There's no better trans ratio for acceleration, power and top speed for a MK2 1.6NA car.

If you had a turbo, that's another story.

To answer your question directly, the 1985 car will have LOWER RPMs at higher speeds, thus raising your MPG notably (about 3-7 MPG).

[Quantum TD]

Things to look for on the 1985 donor trans:

      I've bought, sold and used several transmissions over the years. Since most come out of cars that are not running, I have an external check I run on them before I buy them. So far, I haven't gotten a bad one. Here's what I look for:

1) Input shaft play and leaking. Any play there, and I walk away.

2) Output flange play. If the flanges move from side to side (up/down), or in and out, I walk away.

3) Gear selector movement. If it's hard to shift into any gears while actuating the shift lever (when disconnected from the linkage), I'll pass.
         This is especially important when checking the movement from 1st to 2nd. If it's hard to move from 1st to find second, it usually means the syncros for 2nd are really bad. Now, just about all VW transmissions will have some drag going into 2nd gear in extremely cold temps (like 20 F and below), unless they've been completely rebuilt. Sometimes you get really lucky and they don't, but it's my experience that they all have that to some degree. Thinner lube helps (like GM's Syncromesh).
        I also check the movement into 5th. If it's hard to get into 5th, it means the trans was run low on fluid, and it's killed the 5th gear synchro, and probably done some heat damage to the gears.

4) Excessive leaking. This can mean overheated, or cracks in the case. This can also mean 5th may be bad. Some leaking is OK and normal for a trans with 100-250k on it, but you don't want to see areas washed clean by leaking action around the drive flanges, or erriely clean (or excessively greasy) bell-housings.

5) reverse noise. If I put the trans into reverse, then spin the input shaft, and it makes excessive noise, I'll pass on the trans. Most VW 020 transmissions will make a unique sound when in reverse. You can clearly hear the gears working, but if that sound is too loud, or different from what it should sound like, I won't use/buy/sell the trans.

6)Finally, I put the trans into each gear, and spin the input shaft to make sure none of the gears make noise when power is applied to the input. This will tell me if the gears are worn or broken.

If a transmission passes all those tests, then I'll get it/use it/sell it. I've sold/used a few like that and have had no issues. In fact, my 1981 Rabbit has a j-yard trans that I bought 'cold' with no warranty using all those tests, and it's shifting just fine in low 30 degree temps down here in Tennessee.

[Matteo]

Thanks to all for this GREAT and useful info. As it turns out the car appears to be a 1986 with 177k on the odometer. The transmission in the car is a AGS 516115. The Vin on the car is WVWGG0168GW305704. It appears to be identical to my 1990 GL Diesel. Interior is GREAT, so this will be swapped with mine if I buy the car. The timing belt is intact and the current owner indicated that it was driven to where it sits. Last registered in 2003. I grabbed the half shaft on the drivers side and there was no in/out, up/down or side/side play. I did not get a chance to check the passenger side. Shaft looked new. I shifted the gear shift with out the clutch and it went into all gears smoothly. The trans is dirty, caked with grime, but not washed in any areas. I plan on going back and disconnecting the linkage and seeing how it shifts at the transmission. Can't check input shaft as trans is still connected to engine and car. I will drop the hypoid and see how clean it is.
My questions now are:

Will the body panels fit my 1990 Wolfsburg Edition GL Diesel?
If I get this thing running, should I swap out the whole drive train or just the transmission?
Is the clutch and pressure plate the same on both transmissions? The 1990 transmission is a AWY.

Thanks to all for this info. What a life saver.

Matt

[jtanguay]

my '86 jetta had some real nice gearing.. it was the GLS model.  it didn't have a tach, but i swear 100km/h was around 2200-2400 rpm or so...

[Quantum TD]

Will the body panels fit my 1990 Wolfsburg Edition GL Diesel?
If I get this thing running, should I swap out the whole drive train or just the transmission?
Is the clutch and pressure plate the same on both transmissions?

Thanks to all for this info. What a life saver.

Matt

1) The panels will "fit", but there may be some trim issues: the 1986 has glue-on trim, your 1990 has clips holding the trim on, so you'd have to drill some holes if you want to put your trim on the car. Also, the front fenders on the 1986 will probably lack the 2nd hole for the front bumper slide. You might have to do some finnagling.

2)If you get the thing running, you might just consider driving it until something major goes bad. If your 1990 does not have the Wolfsburg trim package (big-bumpers, thin trim), and the body on the 1986 is better, then you could just register it. Obviously, there are money factors to consider, but I'd hang onto the whole car. If you decide to part out, then get the motor running (pretty easy), then yank the motor and put it in dry storage. Put just the trans on your car and drive it until your motor dies (which, it shouldn't if maintained).

3)Clutch and pressure plate are exactly the same. If your clutch is good (i.e. plenty of grip, and no leakage from rear main seal or input shaft seal) then you can reuse your clutch, or swap the other.

I will suggest that you clean up this replacment trans, and change the input shaft seal, pushrod bushing, and pushrod seal. You should also definitely change the flange seals too (not just the center caps, but the outer ring seals).

Either way, it sounds like a weiner. If you can get the whole car for under say $700, it's definitely worth it.