Oil change on C4 transmission

Discussion in 'Ranchero Tech Help' started by Nico, Aug 7, 2019.

  1. Nico

    Nico In Second Gear

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    Location:
    France
    Hi from France,

    I just flushed the C4 tranny on my 72 Ranchero 500 (converter + pan). Put approx. 5.5 quarts of Type F oil. Gauge is ok but test drive is wrong: Rear is fine, 1 & 2 are pretty fine but Drive is wrong as it slips all the way long. Any advice? Thanks, Nico
     
  2. 65restomod

    65restomod In Fourth Gear BRONZE MEMBER

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    Danville,VT left NJ forever
    Was there an issue with the trans before the oil change?
    What did the fluid look like when it came out?
    Was there any friction material or metallic particles in the pan or filter?
    Did you also add fluid count for the converter? It looks like it may take another 3 or 4 quarts

    You did check the trans in park ,idling correct? Ran it through all the gears ?
     
    Last edited: Aug 7, 2019
  3. Nico

    Nico In Second Gear

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    Location:
    France
    I think previous oil was not type F; gauge level was a bit high, color was dark red pretty clean. Before oil change, Drive was already slippy, especially when cold just after engine start and for the next 5-10 miles of drive.
     
  4. 72GTVA

    72GTVA Administrator Staff Member

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    I don't think 5.5 quarts is enough - the shop manual calls for 10 1/4 US Quarts of type 'F' Automatic Transmission Fluid (ATF). I'd suggest you add fluid, run it a bit to ensure the torque converter is filled, and then top it up expecting that it will take up to 10.5 quarts.
     
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  5. Nico

    Nico In Second Gear

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    Location:
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    I started the engine while filling oil through gauge. And waited until oil level on the gauge stick was fine (between the 2 arrows). Park ok, idling ok, rear ok, 1 ok, 2 80% ok (a bit slippy) and drive wrong...
     
  6. Nico

    Nico In Second Gear

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    Location:
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    What about oil level on the gauge stick? seems ok between the 2 arrows; is it reliable?
     
  7. 65restomod

    65restomod In Fourth Gear BRONZE MEMBER

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    Location:
    Danville,VT left NJ forever
    If the dip stick is original to the vehicle then yes it is reliable
    It is my theory that the seals may have dried up from sitting in the museum causing not enough pressure to hold the clutch pack.
    It may be possible to do a front and rear band adjustment(google c4 band adjustments)
     
    Last edited: Aug 7, 2019
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  8. Nico

    Nico In Second Gear

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    Looks like original... I have a strong doubt with oil capacity: old fluid quantity seems more important than new fluid I added... But when I checked oil level before flush, it was high on the stick, well above the highest arrow...
     
  9. Nico

    Nico In Second Gear

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    26
    Location:
    France
    AS 72GTVA stated, if shop manual calls for 10 1/4 quarts, oil quantity I put is too low, but gauge stick level sent me wrong info then... Shall I put additional 4 3/4 quarts?
     
  10. 72GTVA

    72GTVA Administrator Staff Member

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    Did you check the level with the engine running, idling in Park?

    Low fluid will cause the issues you state.
     
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  11. 72GTVA

    72GTVA Administrator Staff Member

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    Location:
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    Transmission fluid is check with the engine running, idling in Park. The process is add fluid to the level on the stick, start the engine, with foot on brake, cycle the transmission through the gears, place in park, check level by wiping stick and then check again - repeat the process until you have it correct. Add fluid gradually until it registers correct level after the repeating the process outlined above as needed.
     
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  12. Nico

    Nico In Second Gear

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    Location:
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    Ok so I will add some more 4 3/4 quarts of oil then check with test drive. It's true that oil level check on the gauge stick is tight...
     
  13. 72GTVA

    72GTVA Administrator Staff Member

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    Location:
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    I would NOT add 4 3/4 quarts, I would start with 2 and then check the level. Add gradually, run the engine and cycle through the D, 1,2 and return to Park.
     
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  14. Nico

    Nico In Second Gear

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    Location:
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    Ok, thanks. I will do this with additional oil quantity as you mentioned, and will try to read the stick correctly...
     
  15. Nico

    Nico In Second Gear

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    Location:
    France
    Ok I will start with 2 then check and so on.
     
  16. Nico

    Nico In Second Gear

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    Location:
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    Ok Thanks. Before this, Il will make sure to add sufficient quantity of new oil, following 72GTVA procedure.
     
  17. Hillbilly

    Hillbilly In Maximum Overdrive

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    Remember that the fluid expands as it get's warmer. It is important to get the engine and trans warm before the final addition of fluid. Once you think the fluid level is sufficient, drive it at least two miles then park on a level spot while leaving the engine running in park. Now check the fluid level and add more if needed to get to the full mark on the stick. Once the trans shows full hot add no more fluid. After completely cooling off the fluid level will show slightly below full if checked from a cold start. Check the level once more while hot to verify the fluid level is correct. As Dan suggested, add the fluid in small amounts because it isn't easy to get excess fluid back out of the transmission.
     
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  18. handy_andy_cv64

    handy_andy_cv64 In Maximum Overdrive SILVER MEMBER

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    Also make sure you inspect around the transmission casing and the transmission cooler lines to the radiator, to ensure you do not have leaks, including the torque converter drain plug. That one caught me by surprise on my brother's automatic overdrive transmission.
     
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  19. Nico

    Nico In Second Gear

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    France
    Thanks; I will follow this procedure.
     
  20. Nico

    Nico In Second Gear

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    Location:
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    It's fine, no leaks around transmission.
     

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