My 3.90's aren't that great.

[keepsbreakin]

I just had my 3.90 gears put in......they suck. With 3.27's I could get the car sideways with slammin' 1-2 shift. Broke my 3.90's in, and ready for thrashing. Car wouldn't even chirp in the 1-2. T/C was OFF. It felt like it was slower, and track testing confirmed it was no faster. It's average 1/4 e.t.s and speed were the same. Fifth gear feels a little stronger, but 1 thru 4 feel crappy. The motor doesn't seem to rev as fast either....had the gears professionally installed, and was there assisting with tools and filling up rear end with oil. The damn Speedcal is all screwed up as well. DM couldn't help me, and it is there damn product! Speedo reads what it wants... it is pointing to 130mph, then 40, 60, 55, 10, then gets stuck on 20 after five minutes. I am going to go with a set of 4.30's. I am not expecting too much, but for the car to feel slower.....I don't know why. My '99 GT with 3.90's was an animal. My '03 GT is like a V-6.

 

[DC-GT]

Maybe the exhaust pipes got crimped with the lift or something??? Might look around just to be sure... No sevice engine soon lights?

Bo

 

[keepsbreakin]

No, the exhaust is perfect. No check engine lights....I am at a loss figuring this out. The Speedcal I am sure can be worked out. I am disappointed. I should have listened to a lot of you guys.....get the 4.10's or 4.30's.

 

[TARZAN]

Man, it ain't the gears, there is something else desperately wrong if you think that 3.27's are better than 3.90's!!!!!!!!!!!!!

You got problems!!!!
If it is an true Daily Driver, I wouldn't advise you get aggravated and get 4.30's.....

You should get a new speedcal, and find out what the hell is wrong.

-Will

 

[DaNd4Speed]

Man, it ain't the gears, there is something else desperately wrong if you think that 3.27's are better than 3.90's!!!!!!!!!!!!!

You got problems!!!!
If it is an true Daily Driver, I wouldn't advise you get aggravated and get 4.30's.....

You should get a new speedcal, and find out what the hell is wrong.

-Will

Agreed...there's no way that a shorter gear would make you less likely to break traction, that makes no sense at all. There is something else wrong with your car.

 

[sapperstang78]

Man, it ain't the gears, there is something else desperately wrong if you think that 3.27's are better than 3.90's!!!!!!!!!!!!!

You got problems!!!!
If it is an true Daily Driver, I wouldn't advise you get aggravated and get 4.30's.....

You should get a new speedcal, and find out what the hell is wrong.

-Will

I love mine. Something else is wrong.

 

[GinoGT]

4.10's =

Anyway, from what I've heard, a lot of people break even or even run a little slower with new gears at the track. You just need to re-learn how to drive the car.

You haven't done any suspension work since the gears, have you? I noticed aftermarket control arms really do help in keeping the rear end in check. Surely doesn't turn the stock gatorbacks into slicks, but you can tell a difference.

 

[GotMustangs]

I agree with these other guys. There is definitely something wrong with your car. Going from 3.27's to 3.90's should help the rubber peel off of your tires in a much bigger hurry. Did you look at the gears when they came out? Maybe the car already had 4.10's. I'm really not trying to insult your intelligence here, I've just heard of it happening. Kinda like when I went to install my H&R springs: I took the front end apart, and out popped Eibach Pro-Kits. I felt like a total jackass. Good thing the H&R's dropped it another 1/2".

 

[keepsbreakin]

They were the stock 3.27's. Bought car brand new, and the pinion had a 3 27 stamped in it. "Re-learning" is b.s. I have to rev to 5500 and drop the clutch to get some spin. I don't know what is wrong. Maybe the 3650 is screwing up again...in the 15,000 miles I've had it, I am on my third TR3650. Last two just broke without my help, I think the third one might be a little bit of an abuse issue. Or could be the motor...on my second motor from Ford. No ****. I don't know. Hell, Pro-Motive could have sent the wrong gear as well. It looked right. But who knows. Maybe that is why Speedcal doesn't wnat to cooperate on 3.89-3.90-or 3.91 setting. Hmmm..........

 

[GinoGT]

What were the weather conditions like at the track on your old gear runs vs. your new gear runs? Race weight? Car setup? Other mods?

I'd really like to know why your car needs to sidestep the clutch at 5500 to break loose.

 

[Jay03Gt]

Your speedo shouldn't be bouncing around like that, and it maybe a good part of the problem. Also, what about the rear brakes, something didn't happen and maybe the park brake is partially engaged or some thing is it?

Also, what about the backlash? It sin't set up so tight it has no backlash is it? What was the backlash reading, do you remember?

 

[keepsbreakin]

Last 3.27 run was in November....temp was 48*, humidity was around 30%-40%, with full equipment, 1/4 tank 93 octane. 3.90 runs were in 42*, humidity was around 50% I believe, and same set up...all equipment and roughly 1/4 tank of 93. Both with Nitto DR's. Thinking I got Jew'd on the gears....the invoice had 3.90 on it. Car is same tune. Haven't changed exhaust or anything else. Best 3.27 run is 14.06, best 3.90 run was 14.02. At 10,000 miles my '99 told click off high 13's everytime. This 2003 doesn't even feel the same as my '99. Backlash is set at .008 That is where the 8.8 should be. No more than 12, no less than 8 for optimal. Took an hour to finally get the thing shimmed just right. Everything was perfect.

 

[4.6MustangSteve]

Hrm... you should be able to break loose alot more than with the 3.27's. Maybe you just have to get used to them. I know when I had the 4.10s installed it felt like a totally different car and I had to take a while to re-learn how it drove and such.

But even then, I don't think that would stop you from spinning on your 1-2 shift. Somethings got to be wrong somewhere else.

 

[DBMSTNG]

Thinking I got Jew'd on the gears....

please remove that incredibly STUPID comment. Jews have got NOTHING to do with your problem.

 

[keepsbreakin]

Its a figure of speech popular around here. I don't know any Jews or even know anything about them. My part of Texas is made up mainly of Catholics, a few various non-Catholic religions, and that is it. I don't practice religion. I have other things to do on Sunday.

 

[KJ Hoppus]

maybe they put in 3.08s or 2. 90s if they exist

 

[GotMustangs]

Shoulda got the 4.10's.

 

[keepsbreakin]

I'll figure it out when I go back Monday...this post is old...lets use it for some free toast. Going to let another 99-up guy drive it tomorrow. See if he notices a difference.

 

[krly79]

Shoulda got the 4.10's.

, either way, they put the wrong gear in or there is something else wrong. BTW, how long did it take to get your speedcal?

 

[MotleyCrue]

JC is Jewish, your in good company