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GT Transmission/3.73 rear

567 views 6 replies 5 participants last post by  dirtyd0g 
#1 ·
I'm toying with the idea of getting a FRPP Pumpkin at some point when I have the money... The problem is I have a '99 GT transmission in my Cougar. I know there are no gears that wor *reliably* with the 8 tooth OP shaft, and I would rather not go the way of a speedcal (want to keep it clean). That said, it would mean I would have to tear down the transmission to replace tho OP shaft.

I just skimmed through Trans 101, and found that the older (95) OP shafts where made of a weaker material than the 98+ ones, so I shouldn't use the OP shaft from my 95 tranmssion. What else should I do while in there (I've done the JMod)? This transmission could end up behind a 450hp DOHC 4.6 (maybe), so I would want to build it to handle that, possibly build extra in...

I'm guessing the following:
-New 7 tooth OP Shaft
-5.4L Panetary Carrier
-Forward Sun Gear
-7 direct clutch plates
-6 forward clutch plates
-Wave plate for SC (5.4?)
-HP intermediate clutch friction (if I drill to the >450 for the intermediate)
-2.7" OD Servo
-5.4L EPC Solenoid

Am I on the right track? Any other words of wisdom?

Thanks.
 
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#3 · (Edited)
oops... too bad I didn't have the money when they where fir sale for likg $550 (still don't, but...)

JustinH said:
Besides 373 isn't enough gear anyway. Get a mark8 housing and DIY.
/that might be a cheaper way to go... I don't want to go TOO nuts with the gears... I'll probably need to get a MMX driveshaft with 3.73's anyway, but going ftom 3.08 to 3.73's would probably be a BIG difference off the line...

ETA: What vehicles had the 5.4L/4R70W? It seems like all the trucks have the 4R100.

I'm looking for the less expensive meathod for the same result. I would think (I could be wrong though) that it would cost less to get the replacement parts (rebuild kit +) than get a new (used) transmission, get a rebuild kit, and any additions.
 
#5 ·
1998 Mark 8 output shaft.
 
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