5.9 into my 98 gmc

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MISPLACEDBIKER

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Sep 11, 2010
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Thinking Of Getting A Cummins For My 98 Gmc 2 Wheel Drive 3/4 Ton. I Love My 454 But Since We Cant Seem To Buy Real Gasoline Anymore My Performance And Economy Is Really Getting Pathetic. 12 Valve Or 24? I'm Thinking 5 Speed . Or Will My 4l80 Hold Up? What About My Anti-loc Brakes And Cruise Control. Any Ideas? I Have A 2001 2500 Dodge Spotted For A Doner Vehicle
 
I would find a Dodge truck and use whatever transmission comes with it A 94-98.4 would be a good choice P pump motor Makes plenty of power and simple to wire up.
Standard transmissions would not matter what year but autos 94 and early 95 have a 47rh which means 1,2,&3 are mechanically shifted lockup and overdrive are electric. Late 95 up have a 47re which like the 4l80e is all electronically shifted which would require a stand alone controller or the dodge computer. Rich
PS. Welcome to Comp D
 
I dont drive it enough know as it is still a work in progress I did get 1 reading and it was 14 if I remember right. this was all city driving with a heavy foot and with 410 gears.I have a set of 321s that will help a lot. The goal I have set for it is 25 mpg when completed .Rich
 
im doing the same thing except mine is going into an excursion but i am also using the 47rh 2wd trans. was it difficult at all to get the overdrive and lockup wiring and switches to work properly in that trans rs359? thanks and as for the GMC i would use 94 to 98 12v not the 24v. to many issues with injection pumps and wiring. As for trannys deffinatly go 94 or 95 47rh. pcs standalone controller is like 900 bucks. 5 speed would be nice and better for fuel economy. will also hold an easy 500 hp with the right clutch. and even more with a better input shaft and double disc clutch.
 
I used toggle switches until I get the Suncoast controler it controls lockup and overdrive basically 2 speed activated switches in a programable box. I used pressure activated switches with the first Suburban they worked but were a little quirky.Rich
 
As for the wiring you just run power to the middle wire and ground the other 2 for lockup and OD real easy. The ground would go through whatever switch you choose into the lockup and OD.Rich
 
so what you do is flip one switch for od. then if you want lock up you flip the other switch too? or is it one or the other? also are you able to lock up the convertor in any gear? thanks
 
Each one is independent of the other except it wont come out of overdrive when the converter is locked however you can lock the converter in 3rd then lock up the converter. I would recommend using a 5pin relay hooked to the brake switch, for the converter, so you dont fold up the flexplate on accident
Rich
 
think i will go for a 24 valve with a p pump conversion.... if i can find a parts truck with a 5 -speed i will go that way if not i will use my 4l80 with some mods...... made the first step found a killer deal on some auto world mounts,,,, here we go
 
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