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Item Posts    Sort Order

Transmission not engaging

New User
Posts: 1
Joined: 01/12
Posted: 06/12/13 05:51 PM

I had my mustang out a few time this year with no issues until now.I took it out of the gargae and parked it in the driveway for a few hours, no issues when i did this. A few hours later I went out to move it back into the garage, the transmission lever would go into each gear (C4 Transmission) but no gear would engage, the engine would only rev. I assumed the transmission fluid was low, so I added 1/2 litre. Took it out for a drive and came back to check the transmission fluid and now it is reading over full, so the transmission fluid was not the issue. Any suggestions on what the issue could be? It seems to shift fine now.  
67 Hardtop
Dark Moss Green
289 2V V8
C4 Automatic

Post Reply
Posts: 223
Joined: 04/13
Posted: 06/13/13 04:14 PM

when C4 transmission fail to engage... the inner seal on the forward clutch drum/piston has been overheated and shrunk ..

the fluid bypasses the seal and cannot engage the forward clutch pack..  so you get NO forward and NO reverse until the ATF heats up and the seal swells slightly... i have not only seen it many times.. i have experienced it personally...

this usually happens after an overheat.. or when the transmission was operated LOW on fluid.. where the forward clutches were slipping , heat built up and shrunk the O ring...

C4 transmissions are NOT hard to rebuild and only need really a decent set of hand tools... and some creativity..

there are several articles spread out in the 40 or so magazines on this site on rebuilding the C4...

there are also videos on it..

C4 transmissions are slightly different between the 66 to 69 models...  the 70 model has one slight difference than the 71 up C4 transmission..  so you will need to identify the TAG bolted to the side of the transmission... to order the proper parts...

if the tag is missing...

find the casting numbers on the transmission CASE...  not on the pump or tail housing.. or on one of the side covers...

on the CASE...

more if you reply..  and you feel like doing this one yourself..  

Post Reply
Posts: 223
Joined: 04/13
Posted: 06/13/13 04:19 PM

here are a few articles to read..  

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