C4 Issue

[dwm9ersfan]

Not sure how to explain this but when it shifts from first to second it sounds like the engine speeds up and a slight squeal then it seems fine. Any help would be appreciated.

 

[Don C]

Fluid level, fluid and filter condition?

 

[dwm9ersfan]

Fluid level is good and no burnt smell, filter not sure just got the car yesterday.

 

[Kilgon]

Fluid level is good and no burnt smell, filter not sure just got the car yesterday.

Could be a number of things from a bad modulator valve, valve body issues to the bands and clutches or a weak pump. Since you just got the car I would change both the transmission and engine oil and filters. Always helpful to have a "starting" point.

Start with a complete fluid change which would include draining the torque converter. Note - On some of the C4's the torque convertors don't have a drain plug. Check and see what' s in the pan when you drop it. Look closely for any signs of metal flakes or cellulose material from the bands or clutch disc. Check the old filter over good also when changing it for any foreign material. I wouldn't drop the valve body unless I had a reason to. Make sure you stay with type F fluid. Should take about 10 quarts to fill back up if you drained the convertor. I would also replace the vacuum modulator valve while your under there. I would replace with an adjustable one.

 

[DAverkamp]

Fluid level is good and no burnt smell, filter not sure just got the car yesterday.

Darrel,
Welcome again and sorry to hear your woes have started. I know you received her yesterday and I'm not sure how you bought her or if someone you trusted checked her out or? My advice would be to find your "guy or gal" shop and have them give it the once over twice to check everything from where the four patches of rubber touch the ground up to the tip of the antenna. Safety checks first and foremost. I'm not trying to being an alarmist but if you are having issues off the get go, it's better to find anything else and fix now so your summer isn't ruined by having a major issue thats not identified asap IMO.

 

[dwm9ersfan]

Darrel,
Welcome again and sorry to hear your woes have started. I know you received her yesterday and I'm not sure how you bought her or if someone you trusted checked her out or? My advice would be to find your "guy or gal" shop and have them give it the once over twice to check everything from where the four patches of rubber touch the ground up to the tip of the antenna. Safety checks first and foremost. I'm not trying to being an alarmist but if you are having issues off the get go, it's better to find anything else and fix now so your summer isn't ruined by having a major issue thats not identified asap IMO.

Yep thats my plan, transmission shop first then to hot rod shop for the rest of the checkup.

 

[Austin Vert]

Hi Darrell,
Sorry to hear of your C4 slipping issue. Great help and advice from the Guys above. I cannot give good tech advice here, as i don't know a lot of detailed technical matters with transmissions. However, i can pass onto you my personal recent C4 problem i had, and the story i went through to get it repaired. You may find my story helpful, and so shine a light from another angle to help solve your problem.

See my link here ......................................................

https://7173mustangs.com/threads/austin-verts-tranny-rebuild.40512/
Thanks,

Greg.

 

[Hemikiller]

The 1-2 shift is accomplished by applying the intermediate band. If it's improperly adjusted, worn, or the seals on the apply piston are leaking, it could cause a problem. The squeal could be noise from a cracked seal, or metal to metal contact of the band to the drum, or from the valvebody itself. The trans shop should be able to sort it out for you.