I put in a Transgo SK C5 that is for 73 and up C4 and C5s. I tried that with an H servo and a new green stripe modulator to try and improve the 2-3 shift, but none of that worked. When I put in my junkyard special 302, the 2-3 shift really got bad under acceleration.....and I finally decided that there was no option other than rebuild. I had expert help though, as a friend of a friend let me re-build it in his shop, with good lighting, a solvent tank/parts washer, stainless steel table with a drain......lol, I was spoiled. I washed all the pieces, and put most of it back together under supervision. I, in return, built the guy a hand built brass 1/24th scale slot car chassis (these take about 12 hours to build from scratch) that our club races.....so I got an A-1 rebuild and he got one of the finest OSCAR club slot cars available. ( Blah-brag-brag-blah) I had the converter rebuilt and tuned to be a high stall stock converter....supposed to stall around 1800-2000. I kept it conservative, as I think my engine has a fairly wide power band. If I give away some potential off the line, I'll just call it traction control. I really need to get to a track now and let er rip for a 1/4 mile.
lol....I had good supervision. Whatever possessed me to dive in ran away to hide as it was coming apart. It was fun though.
Type F. The only thing that is upgraded from stock is the shift kit, and the direct drum went from 3 to 5 frictions. I couldnt find any drums that held more than 3, so a new groove for the snap ring got cut into it by a friend of a friends friend. I thought 250 I6 had the same drums as a v8 C4, but I guess you never know until its apart.
Type F will give a little firmer shifts than Dexron/Mercon, GM guys often used it in turbo 350 & 400 to get a bit more kick. The B&M Trick Shift fluid was mostly Type F. It does require change at shorter intervals. I used F for nine seasons of driving & racing in my T-Bird AOD, 5.0 blew up, trans is still fine. Also used F in a AODE that had a 2nd gear shift flare problem, ran 98K miles(131 total) before it finally gave up. Bandaged Aerostar sluggish shifting A4LD with F, was still operating at over 150K when retired. Sister vehicles were retired as A4LD died, none made it more than 95-110K.
Curious (since I'm uneducated on transmissions); why the need for a shift kit when Type-F already shifts quick & firm? I would think that would be more appropriate for transmissions running Dexron/Mercon...
Fluid difference doesn't compare with a good shift kit. The AOD I mentioned has a Transgo shift kit & type F, otherwise stock V6 Super Coupe transmission. Even with F, before kit, that transmission flared on 1st to 2nd shift. First time at track, Trick Flow headed 5.0 made enough power to twist off the inner input shaft(3rd & O/D gears). A hardened shaft fixed that.
When I installed the transgo kit for my C4, I did not leave out the little "puck" the instructions said to leave out for a firmer shift, as I thought the 1-2 shift was firm enough. The kit seemed to make all the shifts happen with no delay. I am new to all this stuff.....the next time I mess with a C4, both drums will get 5 frictions and larger capacity drums will be found in advance of teardown. I wonder if pan fill C4's out of trucks/vans would have the bigger capacity drums?
