While in theory his will work fine.. switching gear ratios in the pcm is not easy at all... you would save yourself headaches if ypu swapped in the hd gear ratio after you bought the trans. The diff being small is not a problem for most anyone.
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10:58 AM
Dennis LaGrua Member
Posts: 15897 From: Hillsborough, NJ U.S.A. Registered: May 2000
The HD differential was added tp the 4T65e especially to provide additional strength for the more powerful engines. A standard 4T65e may work but the extra margin of safety of the 4T65eHD is beneficial. As for the gearing adjustments in the PCM alluded to by darkhorizon,I agree that it would be a PITA to change. If I were running a 4T65eI would just try to find a GM OBD program that was set up to troll that box and import all of the transmision table data into the GTP PCM program.
------------------ " THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Powerlog manifold, Northstar TB, LS1 MAF, 3" Flotech Afterburner Exhaust, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, HP Tuners VCM Suite. "THE COLUSSUS" 87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H " ON THE LOOSE WITHOUT THE JUICE "
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02:03 PM
nosrac Member
Posts: 3520 From: Euless, TX, US Registered: Jan 2005
Changing the ratios in the program takes about five seconds when reprogramming a PCM so no big deal there. I have built many 3800SC Fieros with autos with most being the HD tranny but still quite a few were non HD trannies that are still holding up to lots of abuse. Dan
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03:50 PM
iluvsd619 Member
Posts: 1036 From: san diego, ca Registered: May 2005
So he can use the tranny we just have to get the ratios changed in the ecm. Sounds like a plan.
You don't really need to change the ratios. The only downside is that the speedometer will be a little off and the trans may shift a little early. Hell, MOST swaps have this issue anyway because the Wheel/Tire height doesn't match the PCM settings.
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02:14 PM
darkhorizon Member
Posts: 12279 From: Flint Michigan Registered: Jan 2006
You don't really need to change the ratios. The only downside is that the speedometer will be a little off and the trans may shift a little early. Hell, MOST swaps have this issue anyway because the Wheel/Tire height doesn't match the PCM settings.
the whole torque converter melting is no big deal either I guess.
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09:35 PM
PFF
System Bot
iluvsd619 Member
Posts: 1036 From: san diego, ca Registered: May 2005
You don't really need to change the ratios. The only downside is that the speedometer will be a little off and the trans may shift a little early. Hell, MOST swaps have this issue anyway because the Wheel/Tire height doesn't match the PCM settings.
the whole torque converter melting is no big deal either I guess.
Really? Come on man..Melting? I have ran 3.29 single chain setup in my trans for 6 years now with not mekted convertors and little issues. Changing the settings for gears and tuning it right isnt anything difficult either.
