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3.73 to 4.88 Gear Swap Problems **RESOLVED, STEEDA TUNE FIXED ALL ISSUES**

Briebee72

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@L0566Bullitt so if I may ask after all said and done what did changing the gears cost ya over all to get everything dialed in? gears, install, tune.... IM guessing about 2500ish give or take.
 
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L0566Bullitt

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@L0566Bullitt so if I may ask after all said and done what did changing the gears cost ya over all to get everything dialed in? gears, install, tune.... IM guessing about 2500ish give or take.
Gears purchased/installed were $1,579.30 and the tune (SCT X4 programmer and 1 Steeda 4.88/93 octane tune) was $641.95 so $2,221.25 total.
 
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Hi-PO Stang

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Glad to hear all issues were resolved by using the Steeda tune. Good that persistence won out over electronic issues. We all benefit from your experience. Those Steeda engineers know their stuff. Some day I would like own a Steeda modified Mustang.
 

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Now that the OP has had the issues resolved with the 4.88 gear swap , I would like the OP to list the process he would take to install 4.88 gears as a reference for the rest of us interested in doing a similar swap. A summary of the parts used and who manufactured the parts would be great.
 

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L0566Bullitt

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Now that the OP has had the issues resolved with the 4.88 gear swap , I would like the OP to list the process he would take to install 4.88 gears as a reference for the rest of us interested in doing a similar swap. A summary of the parts used and who manufactured the parts would be great.
1. Called East Coast Gear Supply and setup an appointment to have 4.88s installed. They used a Yukon gear kit.

2. Gear install messed with the ECM. Took car to dealer where they spent 2+ weeks but couldn't figure it out. Ordered a Steeda tune hoping it would resolve all the issues.

3. Got car back from dealer, installed Steeda tune. Car has run perfectly for two days with no DTCs thrown.

Some notes to consider:

- I notice a slight rumble/vibration after the gear swap. Nothing unbearable, but you may notice it. Called ECGS and they said this is very normal.

- Between the 4.88s and tune, it's so fast I'm considering cancelling my Whipple Supercharger purchase. Sometimes it will break loose on dry pavement half way through 2nd gear acceleration. Acceleration is insane and I'm really happy with it now.

ECGS_Gears_receipt.png


gears_dealership_dtc_receipt.png


steeda_tune_receipt.png
 

Balr14

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I know this wasn't the objective, but have you observed what impact this swap has on your gas mileage? Just curious.
 
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L0566Bullitt

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I know this wasn't the objective, but have you observed what impact this swap has on your gas mileage? Just curious.
Tbh I keep the accelerator mashed most the time.

But in all seriousness I did notice with this tune, cruising at 60ish it's pulling high vacuum so I think I'd get really good mpg. I doubt you'd notice 1 mpg difference.
 

Norm Peterson

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But in all seriousness I did notice with this tune, cruising at 60ish it's pulling high vacuum so I think I'd get really good mpg. I doubt you'd notice 1 mpg difference.
Relative to the torque available at the higher revs you're running, you're using less of what's available so this doesn't surprise me all that much. We'd probably have to see a BSFC curve to get much better of an idea.

Around town mpg might surprise you if you start upshifting earlier than before because the deeper axle gears make that a more reasonable thing to do.


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Some notes to consider:

- I notice a slight rumble/vibration after the gear swap. Nothing unbearable, but you may notice it. Called ECGS and they said this is very normal.
Really glad you got the software side sorted out but having swapped ring and pinions on a variety of cars in the past I'm not sure what you described above is "very normal".
 
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L0566Bullitt

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Don't mind the incredibly slow shift. Kinda hard to hold my phone, steer, and shift when the rear end likes to get squirly



 
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A good forum read on a Sunday afternoon. Glad to see that it looks like it all worked out for you, Jon. I enjoy someone's thinking "outside the box" to improve what they think is not right with their car. It falls in line with drag racer's innovation: going faster within a given space. Kudos to Steeda for their involvement: problem, cause, solution. This opens the door for the rest to consider what L0566Bullitt accomplished. I used to teach my classes that it's always easier and cheaper to learn from someone else's experiences.
 
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L0566Bullitt

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A good forum read on a Sunday afternoon. Glad to see that it looks like it all worked out for you, Jon. I enjoy someone's thinking "outside the box" to improve what they think is not right with their car. It falls in line with drag racer's innovation: going faster within a given space. Kudos to Steeda for their involvement: problem, cause, solution. This opens the door for the rest to consider what L0566Bullitt accomplished. I used to teach my classes that it's always easier and cheaper to learn from someone else's experiences.
Between the gears and tune, it's literally a different car. I'm SO happy with the combo
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