gears on automatic with no programmer?

[kuma]

Read the tranney articles at this site.

http://tccoa.com/articles/tranny/index.html#

 

[VicRattlehead]

The J-Mod will help to correct for the gears by allowing the shifts to occur quicker. Shift points will be alittle better but the mph and odometer will still be off.

that wont help it enough. you need to do this along with the tune to change the commanded shift point lowering it so that the tranny will complete the shift at the right time/rpm.

original poster, if you do NOT get the tuner, DO NOT try to go WOT 1-2 and 2-3 shifts if you do youll see that rev limiter alot. and we all know how good that is for the car.

 

[kuma]

Keith,
Agreed that the J-Mod will not be enough, but it will help some until fswd gets a programmer. It just seemed like fswd was short on cash and the j-mod is a relativly cheap and goes well with a programmer.
I had a '98 GT automatic and with 3.73 gears, no tune, and a 23 tooth speedo gear (that got chewed up), I was WOT shifting 1-2 at around 5900 rpms. Not very far from the rev limiter. Everything got taken care of with a speedcal and SCT tune.


Thanks,

Clayton

 

[cronin49]

you can drive around with 4.10's without problems for the most part. but i wouldn't advise it.

the car will drive fine because the shift points and torque convertor functions are programmed by MPH and throttle position for normal driving. so if the car normally shifts from 1st to 2nd at 20mph with 3.27's, it will shift at what it thinks is 20mph (actually 16mph) with the 4.10's. WOT shifts are programmed by RPM. this is a little more of a concern than normal driving shifts. with the 4R70W, there are Commanded shifts and Actual shifts. what that means is that the computer "commands" the shift at say 5000rpm but it takes the transmission about 1.5 seconds to fill up the clutches needed to make the shift. in that 1.5 seconds of time, the RPM rise another 1000rpm to 6000rpm. so even tho it's commanded at 5000rpm, the actual shift is at 6000rpm. now when you add alot of power OR change the gears, it increases how fast the RPM climb. just for reference, let's say that instead of climbing 1000RPM in that 1.5 seconds it takes to fill the clutches, it now climbs 1500rpm. your new actual shift point will be 6500rpm. you'll start banging against the rev-limiter. a new tune can lower your commanded shift from 5000rpm to 4500rpm to compensate for this. so between that and the 20% or so extra odometer mileage you'd be putting on the car, i highly recommend you get it tuned. and don't forget a tranny cooler.

I guess the guys in MM&FF don't know what they're talking about then. I stand by what I said, you will ruin your transmission. Are you going to buy this guy a new tranny if he follows your advice, which is wrong? It won't go right away, it will take time, but it will break. Your time is coming too.

 

[SilverFoxbody]

get it tuned after the swap, otherwise you are wasting the potentail of your mods....duh!

The speedo can be corrected, that is minor when compared to performance IMHO

 

[VicRattlehead]

I guess the guys in MM&FF don't know what they're talking about then. I stand by what I said, you will ruin your transmission. Are you going to buy this guy a new tranny if he follows your advice, which is wrong? It won't go right away, it will take time, but it will break. Your time is coming too.

ill stand by what DBMSTNG said because he is absolutly correct. MM&FF can lick me, cause they only publish what they get paid to publish right, wrong, or whatever if you pay em enough money they will publish anything. i havent read one of thoes rags in years because of it. as long as he doesnt rev the crap out of the car, it will be ok for now, but if he wants to do any spirited driving hes just asking for problems if he doesnt get it tuned.

 

[DBMSTNG]

I guess the guys in MM&FF don't know what they're talking about then. I stand by what I said, you will ruin your transmission. Are you going to buy this guy a new tranny if he follows your advice, which is wrong? It won't go right away, it will take time, but it will break. Your time is coming too.

should i really go into detail how many times MM&FF have been wrong? hmmm, i seem to remember them saying porting a stock plenum gained like 8-10rwhp. that was proven false by a number of people. i also remember them suggesting the use of a shift kit that was known to cause problems with the 4R70W. i think they even recommended larger throttle bodies on stock plenums, which was proven to lose hp.

yes MM&FF is wrong. the trans will just shift a little sooner and the torque convertor will lock up a little sooner than stock. that's it. as long as you have a trans cooler, and don't do anything stupid, it will be fine physically. do i recommend doing it? no, it will rack up extra miles and you won't gain the full benefit of the gears without it.

 

[propellerhead]

I guess the guys in MM&FF don't know what they're talking about then. I stand by what I said, you will ruin your transmission. Are you going to buy this guy a new tranny if he follows your advice, which is wrong? It won't go right away, it will take time, but it will break. Your time is coming too.

Can you post the reasons why MM&FF said it would break, instead of just saying that MM&FF said it would break?