C-4 trans question

[junkyardjeff]

I have a friend that has a C-4 that when put in drive will shudder on take off and will shift fine,it will not shudder when dropped in low and shifted manually.  When I drove it I noticed when put in drive it slowly went into gear and when I went from park to low it went in right away so I am guessing it could be in the valve body,anybody have any ideas.  Jeff

[Crosley.In.AZ]

I have a friend that has a C-4 that when put in drive will shudder on take off and will shift fine,it will not shudder when dropped in low and shifted manually.  When I drove it I noticed when put in drive it slowly went into gear and when I went from park to low it went in right away so I am guessing it could be in the valve body,anybody have any ideas.  Jeff

what is the history on the tranny? mileage , age , rebuild recently , set for years , low mileage-old age??

When you manually shift the trans to a lower gear..... the design is the main line pressure is boosted up.....= no shutter.

[junkyardjeff]

Its a 80 fairmont with about 56,000 miles,we did a complete fluid change with a filter and still the same problem.  I think it sat for awhile before my friend bought it and the modulator valve went bad a few weks ago and we replaced it and worked fine untill now,it was sucking the fluid out.  Jeff

[Crosley.In.AZ]

Its a 80 fairmont with about 56,000 miles,we did a complete fluid change with a filter and still the same problem.  I think it sat for awhile before my friend bought it and the modulator valve went bad a few weks ago and we replaced it and worked fine untill now,it was sucking the fluid out.  Jeff

hard internal seals.

very common on old or  high mileage C-4 type trans.

You might add a quart of 10w-30 motor oil... it will help for a short while.

Trans is at deaths door

[junkyardjeff]

I think it was to quarts over full of trans fluid so I sucked out two quarts and put in a quart of the trans X mechanic in the can and it worked fine,we are only used to filling trans for V8s and since it was behind a 200 six it has a much smaller torque convertor. I was the guilty one for putting too much fluid in,I never had a small six and put in fluid like it was a V8 and it was blowing fluid out the vent too.  All the Ford sixes I had were the 240/300 and used the same torque convertor and trans as the V8s,I think he had too much fluid in it before we did the fluid change as the modulator valve went bad and he dumped in a bunch as he drove it smoking out the exhaust.  Jeff