First let me say, I did do a search on this and didn't really find anything that helped "much". We have a 74' grabber with the 250 I6, yadda yadda and all that blah. How hard would it be to put a AOD trans in this thing? I understand this wasn't the strongest transmission, but our C4 seems to be having some "problems" and to be blunt, I don't feel like "screwing with it" anymore. I am at the end of my patience. I do ALOT of driving on the interstate, and around here you better be able to do 85 or get the hell off the interstate. She drinks the gas running 70... Not dead sure on RPM's but it's close to 3,100 at 70. The bro seems to think that this "Automatic Overdrive" trans is the answer to our problems (I think the T5 is, but whatever). My main concerns are getting a flexplate/torque converter that will work with the 250 I6, and what will have to be done drive shaft wise. I'm going junkyarding this weekend... Sooner or later it will have a 302, but right now we do not have the time (daily driver) or money to mess with it. Other then that I'm happy.
you need a 164 tooth flexplate for the aod, if youve got it youre set,the only thing you gotta do is move the trans mount back. (driveline should be fine) If not, im not sure about what flexplates are made for that engine....anyone???
I vote T5 because its arguably stronger than the AOD, sucks up less power, and is more fun Plus, if you get it set up for a T5, a Tremec becomes a bolt-in upgrade down the road.
If you are tired of "screwing" with the C-4......just wait till you try to figure out all the "ins and outs" of putting in an AOD. A C-4 is a walk in the park.
I vote T5. AOD bogs a 302 pretty good, I'd hate for all that work swapping to actually make it worse... The AOD swap is certainly an attention getter, but after going through it all, having knowledge of all the catches, the hardest part was getting the shifter linkage right.
The C4's problem is it just never really shifts "right". 90% of the time it doesn't shift back down to first gear when you stop at a redlight which makes it bog and hardly move when you go to take off. Shifting down to 2nd manually seems to help that. And sometimes you will just be driving along 55-60 mph and it will just shift into passing gear for reason and send the RPM's through the roof. Thanks. I think I'm going to try and talk him into a T5, like I wanted from the start...
Sounds like the kickdown may be misadjusted if it kicks down for no apparent reason. My C4 does not seem to downshift into 1st at a stop either most of the time. I don't think it's in my head.
For What it is worth, I agree with Matt, I had a problem with my c-4 not shifting at the right points, had to hit 25 to get to 2nd and 60 to hit 3rd, turns out the kickdown linkage was covered in rust and was stuck in the "kicked down position", maybe yours is sticking then letting loose, causing erratic behavior. I hit mine with w-d40, and what I thought might be a rebuild, ( and fortunately what the guy I bought it from thought was a rebuild) turned out to be fixed with zero investment, mine hsifted like a dream , ( that is until I learned the flexplate was missing teeth) Still trying to find time to get that done.
It shifts to second at about 15. The kickdown works(moves) fine, I've adjusted it several times and it never seems to really change. I didn't know there was a 3rd gear... 3rd must not be working. Right now I have it adjusted so that it pushes the kickdown with the pedal a little under half way down. I'm to the point that I'm about ready to disconnect the kickdown. I'm not one to go rigging things, but all it does is go screwy when you hit it. Before I go doing something that I regret, do you guys have any tips on properly adjusting the kickdown? I'm going to a few junkyards this weekend to take a look at what my options are. If I can find a good T5, I'm getting it. I appreciate it.
Jamie, pull the tail housing off of yours and replace the governor valve, make sure the spool valves in the replacement are free, and that the springs have tension. After that make sure that when your shifter is in drive that the trans is also all the way in drive. It sounds to me like something is off on the linkage which will in turn cause the tranny to getra little warm causing the governor valve to expand and freeze up. Ive built C4s on the bench for many people who did the installation themselves and had this same trouble over and over. Just ask if you need more info.....
also, adjust that kickdown so it only picks up the last 1/4 throttle. no second? run the trans through the gears manually starting from a dead stop in 1st. should shift from first to second fine manually. If it doesnt shift a second time when you put it in drive, you could have a broken second gear band causing it to go directly from first to third.
Cabinator, I just went out and tried shifting it manually as you said. Tried to shift from first into 2nd at about 25 mph, nothing happens, it just continues to run along the same as if you didn't shift. I gave it some gas while leaving it in second, and at about 45 mph it jolted into what I assume is 3rd gear, and crusied along as normal. Trying to shift it from 2nd to 3rd manually, the second you shift it into normal drive, it lets go completely and starts reving through the roof, then a few seconds later it "catches" and throws you back in the seat, then takes off and drives normally. My dad keeps saying something about a vaccume modulator valve? I crawled under the car and the 2 vaccume lines are hooked up and everything seems normal to me.
C-4 THE LINES MAY BE CONNECTED BUT THE ELBOW IS BAD ABOUT DRYING OUT AND SPLITTING CHECK VACUMN AT THE MODULATOR AND ALSO DID YOURS HAVE A RETURN SPRING FROM THE KICKDOWN TO THE CASE? EVERY 250 I'VE SEEN HAS ONE JUSTA THOUGHT RON
