Logan K Posted April 15, 2014 Share Posted April 15, 2014 Last night my buddy picked up a 87 4wd sedan with the 3 auto. The motor is in great shape, looks to have had head gaskets and the timing belt done at some point not too long ago and it has a Weber on it. However, it won't shift into 3rd gear, and we are planning on 5 speed swapping it. What all am I going to need? So far I know it needs a clutch kit, flywheel, pedal assy, clutch cable...the rear diff tag says its a 3.9 but I thought all the automatics came with a 3.7 rear end, or is that just the 4eat cars? Is the spline count different on the axles, and if so are we going to need to swap front hubs? Couldn't really find much info on this swap but if there's already a thread about this id appreciate a link to it. Thanks guys! Quote Link to comment Share on other sites More sharing options...
TheLoyale Posted April 15, 2014 Share Posted April 15, 2014 (edited) You've got it about right, you will also need the 5spd tranny crossmember. The 3AT cars did also come with the 3.9. I think it was a matter of FWD and 4WD being the difference in 3.7 and 3.9. The stubs should be the same. The Turbo cars had the different spline count. Is this going to be a Push-Button 5spd or a D/R setup? As for the wiring for the push button 5spd I'm not 100% sure. -Tom Edited April 15, 2014 by TheLoyale Quote Link to comment Share on other sites More sharing options...
Logan K Posted April 15, 2014 Author Share Posted April 15, 2014 Well I'm dropping the pushbutton 5 speed out of my Loyale to swap with a D/R 5 speed at the same time so that would be the most availabe choice, however you raise a good point, I don't know how the hell that pushbutton system really works. I suppose I could rob whatever is needed off my loyale, but going dual range might be easier in the long run. Propeller/driveshaft length is different between the autos and 5 speeds as well correct? Quote Link to comment Share on other sites More sharing options...
TheLoyale Posted April 15, 2014 Share Posted April 15, 2014 Yes, I believe the front shaft is what changes in length. Quote Link to comment Share on other sites More sharing options...
wagonist Posted April 15, 2014 Share Posted April 15, 2014 Depends which 5 speed you use depends which rear diff you need. FWD front diff were 3.4xx Turbo part-time 4wd 5spd had different spline counts on the trans stub axles. Everything else 4wd should be the same count, just different thickness shafts. You'll need to bridge the neutral safety switch on the auto gearstick. Should be the thick BW & BY wires (nice time to install a starter kill switch ) You'll need to wire up the reverse lights. Extend the wires from the auto stick through to the gearbox. If you want the 4wd light to work on the dash, need to find those wires & extend through to the trans also. If you're doing dual range, you need to get the switch that sits beside the low range lever (on pre 87 cars). Post 87 trans also had a switch on the trans, but I'm not sure if it was used or not. If you want to use the push-button system, the solenoids with be attached to the left strut tower. The wiring should unplug, though I'm not sure if the auto's had the wiring in the loom. Every manual 5spd I've seen here had a spare plug for this in the body harness. The wires off the gearstick just run along the floor & connect by the left kick panel. All you need is ign power to the gearstick, then 2 output wires from the stick to the solenoids (1 for each), then 2 earths from the solenoids. Plus you'll need the vacuum line from the engine to the solenoids 1 Quote Link to comment Share on other sites More sharing options...
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