I have the gu5 RPO code which is the 3.23 rear end gears in my a4. My brothers 02 ws6 also has the same gear code in the same a4 tranny. Hes running around 1800 rpm's at 60 mph. I have a slight whine from the rear end and am running more around 2000-2050 at 60mph. My rear tires are 315-35-17's. Im wondering if I there is a different gear set up in the rear. Maybe 3.42's or 3.73's. I had the diff cover off the other day changing the fluid but i did not think to count the teeth. Sp what do you all think is in the rear? What are you rpms are you running with your 3.42-3.73's in an auto?

 

Using a gear calculator, with a 25.65" tire the 4L60E in O/D would have the engine turning:

1,768rpm with 3.23's
2,042rpm with 3.73's

Are you sure the converter is locking up?

 

Im not at all familar with automatic transmisions, nor converters. I would have no idea wether it was locking up or not. To be honest, I dont know what it means for a converter to "lock up" or how to see if it was. Ive heard the term used lots and lots of times before, but have never payed attention to stalls or anything dealing with a auto tranny because i never had one until now. Please enlighten me

 

Ok, simple to check lockup......1st off, count the shifts, you should have 3 shifts (1-2, 2-3, 3-4). Once you are in 4th gear, cruise at about 50 mph and hold your right foot steady on the gas pedal, do not increase or decrese pressure! Now, while holding the gas steady, lightly tap the brake pedal, you SHOULD see the RPM's jump about 2-300 rpm's and then drop back down when you release the brake pedal. If it does that, then it's locking up, if not......then it's not! Simple! Hope that helps!
Peace,
Mike

 

I did as you said today. Several times it did exactly as you described. One out of every five maybe it seemed to only jump up between 100-150 rpms. This is an estimate. It took a second longer after i let off the brake for the rpms to go back down though.

Also. Injuneer, you say that it would be 2,042rpm with 3.73's at 60 mph. If gears were installed in the rear end, chances are the speedo was not recal. So it would be off a percentage correct? If so, would the 60 mph and rpm's you gave me be correct, or would they need to be corrected to the percentage the speedo was off?

 

That's cool, mine was just an estimate too! LOL That's sounds about normal. Sounds like you got lock-up! BTW I have 3.42's and if I remember correctly, my RPM's are like 1900 +/- on the stock tach at 60 mph.
Peace,
Mike

 

And you havent changed anything with the speedo right? They have to be adjusted computerly to be accurate after adding rear end gears Im assuming.
So with no changes to that, At 60mph your running around 1900 rpms with 3.42s, correct?

So me running at 2k, by injuneers figures, I would also assume that the rear is housed with 3.73's? Is this a fair assumption?

EDIT: after checking out your profile i see a pcmforless tune. So im guessing that when you had that you had your gear change added in to it.

 

Yes, my speedo is accurate for the gears I have, thanks to PCMFORLESS! They are awesome there!
Anyway, did you just buy the car recently? If you had 3.73's and no speedometer corrections done, I would think you would have some WOT shifting issues.......but I'm not a 100% sure. There's a couple of ways to check exactly what gears you have. The best way to be 100% sure is to drop the rear differential cover and count the gears on the ring and the pinion and then divide! That will tell you for certain what you have. Make sure you got some gear oil, posi lube and silicone before you go doing that though! And be prepared for some stinky fluid!
You can also jack the rear of the car up, mark a line on the tire and on the ground and mark the driveshaft.....spin the tire 1 rotation and count how many times the driveshaft spins. If it spins less then 3 times to 1 time for the tire, you have 2.73's, a little more then 3 times, you have 3.23's, almost 3 1/2 turns is 3.42's, almost 4 times, 3.73's over 4 times, 4.10's! That's just a quick way to get a GENERAL idea. Tire diameter can affect this test a little bit, so it's not 100% accurate either way. But probally close enough for you to guesstimate! Good luck!
Peace,
Mike

 

Yeah i just bought the car about a week and a half ago. I changed the diff fluid the other day but didnt think of even looking at them. I was looking through jegs at the gears and the teeth on both the ring and pinion for our cars. It seemed like the right geras never changed, just the pinion gears went from 11,10,9 for the differernt ratios. I guess im going to have to try and do the tire/driveshaft thing, if i cant figure it out then i might just order some 4.11's and be done with it.