O-FiveCC

iTrader: (10)

I know this has been beat to death, as I have been reading for a couple hours. I think I blew the rear today. I had noticed some very slight vibration/grinding when turning and accelerating. I decide to swap my fluid today. I must have gotten the wrong stuff, because I instantly started getting a clunk. Then on my way back to park my car at the house, I got a grinding/popping from the rear. Feels like I have screws mixed in inside the pumpkin. I'm guessing the rear is toast. Anyway, I have an A4, I was all set on the Eaton Posi and 3.91's, however, I finally came to a post where a member mentioned the 3.91's being better for the m6 guys. Whats good to run in an Auto? Would 3.91's be a good upgrade with the Eaton? I'm still reading, but this will give me something to come back and look at.

Also, plans for the future are 3400-3600 Stall, LS3 top-end and most likely Torquer v.2 cam

gmantheman

I don't that much knowledge about gears for GTO but one of the basic questions is your car your D/D and do you plan on taking it to the strip. If it's mostly a d/d then I think the stock 3.46 may be just fine. I have a M6 with L/T and a MS3 cam and I am happy with the stock 3.46.

O-FiveCC

iTrader: (10)

Not a DD, but I would like it to be fun on the street, which I hear gears do a great job of. And I do go to the track occasionally

Dyno Junkie

Our daily driver has 4.1's.

svede1212

iTrader: (3)

Your symptoms sound like you just don't have the "F" type friction modifier in it. Have you tried adding it? BTW 3.73s are usually used with the A4 altho I'd just get the stall and cam first and see if you still want gears.

MD04Goat

With my stall and cam I would love to have some gears, traction and suspension would need to addressed further. I daily drive and thought the 3.73 would be best for me, but why are 3.91's more affordable and they would be a lot more snappy.

O-FiveCC

iTrader: (10)

Yeah right now 3.91's are the only one's made by Motive in the USA, so they are about $450 as opposed to all the Australian Gears being closer to $700

Svede, do you really think all the crunching and popping that I can feel through the car could mean I just need the friction modifier? I'll tell you what I did, I was reading about trans and rear end fluid yesterday on ls2gto. I read for an hour or more. Found a few running the M1 75/140. One of the guys was a high poster, and I had seen him post useful stuff before. He said he runs the M1 75/140 and likes it because it already has the friction modifier in it. So I went and picked up M1 75/140, I noticed it said something about a modifier being added. I thought I was good to go. Maybe there are different types of M1 75/140 available. I couldn't even drive 5 feet after I got home without it feeling like I had screws in the rear end. When i drained the M1 out though, no pieces came out. Is it worth try some Torco with Ford friction modifier? It seems bad back there

O-FiveCC

iTrader: (10)

Svede was right, added some different fluid with a FM and my car was miraculously fixed lol. Saved me about $1500....However, I still may get some gears, we shall see

svede1212

iTrader: (3)

I can PM you my PayPal for the tip.

O-FiveCC

iTrader: (10)

LMAO!!!Seriously, I do thank you. I can't even put into words how destroyed my rear end felt. Seriously felt like metal shards all inside the diff. The rear whines a little now, but I'm guessing that's because I "eyed out" 2 ounces of FM and may have too little or too much. I even whipped the back end out sideways yesterday and all is good. There is some vibration right after the car shifts to second when giving a little gas. Maybe that's also a FM issue, or maybe u-joints?

O-FiveCC

iTrader: (10)

Used some Valvoline 85/140 with some unknown FM from my buddies shop. I have Torco and the Ford FM on the way, wondering if I should change it out again. Maybe should wait till I get gears.

impulsegoat

iTrader: (4)

That's very good news man. Glad to hear you aren't out all that money. GL with it.