Just bought a 93 F-250 with a 5.8 and a 3 speed auto trans and the shift from 1st to second will not take place under 2500rpm, i am thinking that the bands need adjustment, can anyone tell me how i go about doing this or if i'm barking up the wrong tree.
If it is a 3 speed auto it is quite unusual for `93 and must be a C6. There ia an adjustment for the band but I can`t remember the exact proceedure. If you do a search here you should get it.
However the problem you describe would, I feel, more likely be a vacuum problem. If you look at the trans you should see a vacuum pipe coming off the frame rail to a vacuum modulator on the trans. Pull the pipe off and look to see if there is any trans fluid in it. If there is then replace the modulator. If not check that there is vacuum at the pipe with the engine at idle. Hope this helps.
OK if it is a C6 to adjust the band you loosen the adjuster locknut (recommended that the locknut be replaced every time), torque the adjuster screw to 10ft.lbs and then BACK IT OFF 1/12 TURNS. Hold the adjuster in position and tighten the locknut.
The transmission should be easy to identify if you have an overdrive button (on end of shift lever) then you have an E4OD. If on overdrive and only 3 speeds then you have a rare (for your year) C6.
Hope this helps.
That should read 11/2 turns (one and a half).
Last edited by Lazy K; 03-18-2009 at 12:13 PM.
Definitely does not have an O/D on the selector so must be the rare C6, i will double check the transmission code on the factory label.
Also worth noting that the truck has 204000 miles so i am sure the transmission is getting close to expiring, i tend to drive quite easily so might be able to nurse it along for a few more years if i can adjust the bands so that it does not hard shift into second each time, going into 3rd is fine
As long as it has been treated good the C6 should have some miles left with 204,000 miles on it. I have one in my '94 F250 and it has over 140,000 miles on it and it is still very stout. I am very happy with mine, it has a B&M shiftkit, adjustable vacuum modulator, and it shifts perfect.
The vacuum modulator is likely your problem. But, as said before, check the vacuum at the modulator to make sure you don't have a leak. As for the modulator, I would probably just buy one (they are less than $10) when you get your filter and fluid. They are easy to replace when you have all of the fluid out of the transmission. Fluid will pour out when the tranny is full, so I would replace it when the tranny is empty to avoid the mess and wasted ATF associated with doing it later. The adjustable ones are cool because you can fine-tune how it shifts with just an eyeglass screwdriver, but they are sensitive and it takes a while to get them dialed in perfect.
Listed below is the procedure for performing an intermediate band adjustment on a C6. (I DID NOT SEE THAT LAZY K ALREADY LISTED THIS ABOVE)
1) Remove the locknut from the band adjusting screw.
2) Install new locknut and torque adjusting screw to 10 ft. lbs.
3) Back the adjusting screw off EXACTLY 1.5 turns.
4) Hold the adjusting screw from turning and tighten the locknut 35-40 ft. lbs.
Making the adjustment can be a PITA because you do not have a lot of space and some torque wrenches will not fit in the amount of space you have. Make sure your torque wrench will fit before removing the locknut. Good luck and congratulations on your purchase.
Last edited by 1994 F250: 351, C6; 03-18-2009 at 06:23 PM.
Reason: LAZY K already listed adjustment procedure
Wow, thanks for the explanation, i will certainly be changing the fluids very shortly and will see about one of the adjustable modulators as i like the idea of adjusting the shift timing, i'm not a rev happy sort of person and think changing to second should take waaaayyy before 2500 revs.
Yeah, 2500 RPM is way to high for a shift under mild acceleration. Mine did exactly the same thing when I had a vacuum modulator that was shot. When the intermediate band is out of adjustment downshifts will be really lousy. When I got my truck from my grandfather it needed an intermediate band adjustment and I thought the tranny was shot at first. Coming into my apartment I would make a corner coming up a steep hill and the downshift into first would take forever and I would get a bunch of slip along with it. Doing the intermediate band adjustment completely fixed the problem.
Yep, that would be the C6, there does not seem to be a whole lot of C6s in trucks this age. Mine is a '94 and that was the last year Ford put them in trucks. I have heard rumors that the C6 was available in certain fleet/special order vehicles until '96 but I am not positive.
The C6 is an extremely tough transmission and they hold up real well. My grandfather towed a 10,000 pound trailer with my truck and my tranny is great. With the shiftkit and adjustable modulator mine performs great. I could not be more happy with it, overdrive would be nice, but I just limit my highway cruising speed to 55 mph and I get about 13 or 14 mpg and it even got 15 once. Having 4.10 gears is part of the limiting factor in my cruising speed, if you have higher gears you should be able to go faster, but high speeds are extremely detrimental to your mileage when you don't have overdrive. Flat out my truck will only go about 85.
OK so i checked the modulator and sure enough the hose is full of oil so i do need a new one which brings me onto the next question. When i look at getting 1 online they all come with different color bands, i went and cheked the one i have and there no color.