C4 Problem
 

I have a C4 in my other Cougar & during a pass @ the opener, I put the trans in 3rd and it flared REAL bad. (never did that before) I let off the gas but it felt like it was still in gear so I got back in the gas & it held. Got to the ticket booth & it fell out of gear & I heard something rattling.Got it back to the trailer & checked the fluid. Full & no burnt smell, nice red & clean. Put a pint in anyway & tried again. No go & rattling. Tried again half an hour later, went right into gear stayed in about 30 seconds, fell out of gear and rattled again. It doesn't sound like a really bad pilot bushing in a stick car. It sounds like a rattle. Any ideas where to look when I tear into it? (I want to use this trans in my N/SA car).

Re: C4 Problem
 

Dave,

Sounds like you either broke the stator support or pump gear. Both are rare but possible. Just a SWAG with out pulling it apart.

Pull it apart you'll find the problem quick, there is not much in a C-4! I would check endplay first before pulling pump for reference sake and easy reassembly.

Major weak point/ check forward planetary gear side play, the shims wear quickly in a drag car.

Good luck!

Re: C4 Problem
 

Well thats a little embarassing. Pulled the pan & found several loose bolts on the valve body, one stripped bolt hole & a plugged screen. Fixed them all & going to try @ the track soon. It goes in gear & holds now. :rolleyes:

Re: C4 Problem
 

Good luck to you.

Re: C4 Problem
 

No dice. As I said, it goes in & stays in gear now. But I only have 1st, 2nd, & reverse, no 3rd at all & sometimes it freewheel's in low on decel. From a clutch/band app. chart the Forward & the High clutch are engaged in 3rd. I have 1st & 2nd so that rules out the forward clutch & reverse works so it can't be the high clutch. No bands in 3rd. The low sprag overruns In 2nd & 3rd :confused: Valve body ? What is that spring & plug that the screen holds in ?

Re: C4 Problem
 

Sounds like you still have a valve body issue. Your analysis is correct that all of the elements are working to some degree. However, you could have reverse and still not have third even though it is the direct (aka high) clutch that is engaged for both. Most valve bodies have a much higher line pressure for reverse than for the forward gears, and the load is less in reverse too (highest numerical gear ratio), so it might have enough engagement to make reverse work, but not third where the load is highest (lowest numerical gear ratio). The direct might be trying to engage but not have enough pressure to hold in third.

Another thing that is troubling is where you say "sometimes it freewheel's in low on decel." Whether it freewheels in low on decel is completely a function of the valve body design. If the valve body applies the reverse band in low then it will have engine braking in low (this puts less stress on the sprag). If the valve body doesn't apply the reverse band in low, then it will freewheel on decel in low as the sprag is overridden. If you sometimes have freewheel and sometimes not, that is another indication that there is something amiss in the valve body. It should always free-wheel or never.

Whether you need the spring and plug that is held in by the filter is also a function of the valve body design. I think most fully manual valve bodies do not need the spring and plug, but yours might. If it was in there originally, you should put it back.

You should make absolutely sure that the shifter is adjusted properly too. Most full-manual valve bodies use the manual valve as the only fluid directing element, and if it is not positioned right you can get all sorts of weird results.

Re: C4 Problem
 

The spring and plug are the throttle pressure limit valve and spring. Most manual shift valve bodies do not apply the rear band in 1st, most "shift kits" do, what do you have for a valve body? If the filter was plugged with clutch material, I suspect that's why you have no high gear, all the high clutch lining is in the filter. You may still have reverse but only because the pressure is higher.

Jim Mantle
V/SA 6632

Re: C4 Problem
 

Thank you for the input, really appreciate it. The valve body is a stock ford with a B&M kit in it. The vacuum modulator is not hooked up. The filter wasn't plugged with clutch material, it looked more like thrust washer. I checked line pressure & it pegged my gauge (100 psi).

Re: C4 Problem
 

You probably answered your own question. If you had a thrust washer fail, You would now have excessive end play which can affect location of drums to sealing rings and cause fluid pressure to bleed off.
Chuck

Re: C4 Problem
 

A 100psi gauge ain't gonna cut it.. you will likely see almost 300 in reverse. If you have brass on the filter, it's tear-down time.