Question to '98 GT AOD owners w/3.73 or 4.10 gears

Bubba Z.:

Welcome to the board!

You will need to do the Jerry mod (it's almost free, apart from your time, 12 quarts of Mercon V, and a fresh filter). Find "Transmissions 101" in the Tech Articles/Transmissions section at TCCoA.com and read, read, read.

The shift points MAY need adjusting (they are set in the PCM) if you do not make the shifts quicker (i.e. J-mod). If the shifts are not made quicker, then the engine will probably hit the rev limiter quite often when you go WOT. Around town and moderate acceleration will not be a problem. The SCT Xcalibrator or Diablo Predator will allow you to adjust shift points [some] if you don't want to do the J-mod.

In my case, I had already done the J-mod and I had the PCM reflashed (by none other than Mr. W) and the shift points were spot on (i.e.-no bouncing off the rev limiter).

HTH,

Chris

Bubba Z. said:

How are the shift points on the auto tranny with 3.73's or 4.10's. I'll definately be throwing in some new gears on my '98 GT and was wondering how funky the shift points get. Did you get a chip burnt or retuned or do you just live with it. I'm not to concerned with the speedo correction because my Speedcal will take care of that.

Opinions?

Thanks,
Bubba Z.

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I had a 98GT Auto with exhaust and 4.10s. I can say that the shift points were VERY wierd, and the top end dropped from 150 to 120. I personally wouldn't do gears in an automatic ever again, but thats just me. The Overdrive on the auto transmissions isn't quite like having 5th gear. I have heard people geting up to 150mph with 4.10s in ther 5th GTs, and i can tell you right now my 98 Auto GT with 4.10s wouldn't even touch that. 120 was my highest it was at like 5300RPM at 120mph.

And if you do gears, get a Speed-cal. But I also hear RUMORS that you can't speed-cal auto trannies on the 96-98GT models I dont know where that came from, but when i had my 98Gt and made posts about it, i remember people telling me that. My solution to the 4.10s and Non-pi automatic 98GT....traded it in for a 2002 5spd



I would recommend the same

But goodluck with the gears. And FYI, I paid like $130 for FRPP 4.10 gears
(I think they are like $180 now, but Chris is the man!) from Mustang Tuning.com and the install on them was $200 labor + $80 for extra parts and gear oil. I got it done at Ford from one of the workers as an "afterhours" job.

You said some when you said that you could adjust the shift points what does that mean! I have a 2000 GT w/AODE and was planning to get 4.10's

speedcal is for 99+ only from my understanding, cause I was thinking about gears in my 98 AOD but I said forget it cause I was going to need a whole new tune to fix the shifts and whatnot. I dont see too many people on the boards (here at stangnet) with gears in their 96-98 AOD. Good luck, and let me know how it turns out...

i have almost 100,000 miles on my 96 aode gt with 3:73..never had a problem except for speedo being off over 80 mph. but i've had friends drive along side of me doing 130 and could have gone alittle faster. I too have heard speedcal doesn't work for 96-98 cars. I installed the 23t speedo gear but its plastic so? Someday i'll install some heads and intake and get a tune, then i guess i can have them change the gear and tire combo on the new chip....hope this helps you out.

UDTBadkarma said:

But I also hear RUMORS that you can't speed-cal auto trannies on the 96-98GT models I dont know where that came from, but when i had my 98Gt and made posts about it, i remember people telling me that. My solution to the 4.10s and Non-pi automatic 98GT....traded it in for a 2002 5spd

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SpeedCal works for any kind of transmission for pre-1999 models. No ifs, ands, or buts.

Chris

joshheat25 said:

You said some when you said that you could adjust the shift points what does that mean! I have a 2000 GT w/AODE and was planning to get 4.10's

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You will need to use a chip or reflash the PCM (with an Xcalibrator or Predator) to correct the speedo/odo [they are electronic, not mechanical like the pre-1999 models]. If you do not make the shifts quicker (Jerry mod - see earlier post about the article at TCCoA.com), then the shift will not be complete when the engine hits redline with the new gears. Thus, the rev limiter will kick in (something you really want to avoid). So, with higher numeric gears out back, the shift points need to be lowered (i.e.--commanded at lower rpm or mph [the two ways to do it]). If you do the J-mod, then the shifts will be physically quicker and the shift will be completed before redline. In this case, the shift points may be OK as is.

HTH,

Chris