Author Topic: Automatic transmission shifting at high RPM  (Read 23603 times)

Thierry

  • Administrator
  • *****
  • Posts: 1379
  • Gender: Male
    • Used cars
  • Mustang: Had a 69 Mustang coupe
  • Daily driver: Sunfire
  • Location: Saint John NB Canada
Automatic transmission shifting at high RPM
« on: April 27, 2008, 10:24:00 AM »
 Hells17, a member from the French section has a problem with an automatic transmission on his 67 Mustang. The shifting is brutal and only happens at high RPM. He thinks it's his converter but in my opinion it would rather be a bad clutch pack. Do you have any idea what to check for this problem?

Soaring

  • Global Moderator
  • *****
  • Posts: 4279
  • Gender: Male
  • 1965 Mustang coupe 289, '03 Mach1, 03 Lariat
  • Mustang: 1965 coupe 289, and 2003 Mach1
  • Daily driver: '03 Ford F-150 Lariat
  • Location: Wimberley, Texas
Re: Automatic transmission shifting at high RPM
« Reply #1 on: April 27, 2008, 03:36:36 PM »
Find out if this transmission has always done this since he has owned it.  If so, he most likely has a high stall converter. 
If not, then I would suggest a transmission fluid and filter change. Don't flush it, just drop the pan, replace the transmission filter and replace the fluid that came out. Usually a hard shift like this is due to a dirty transmission filter.
That is the first thing I would do.  Let's see if that fixes it before we tear into the transmission. 

rmodel65

  • Global Moderator
  • *****
  • Posts: 681
  • Gender: Male
  • the mustang man
  • Mustang: 65 fastback modded
  • Daily driver: 1991 gt vert
  • Location: US
Re: Automatic transmission shifting at high RPM
« Reply #2 on: April 27, 2008, 03:49:06 PM »
im assuming its a c4? does he have the vacuum modulator hooked up? and has he tried adjusting it

Thierry

  • Administrator
  • *****
  • Posts: 1379
  • Gender: Male
    • Used cars
  • Mustang: Had a 69 Mustang coupe
  • Daily driver: Sunfire
  • Location: Saint John NB Canada
Re: Automatic transmission shifting at high RPM
« Reply #3 on: April 27, 2008, 04:41:48 PM »
 I told him what you suggested and we'll see what happens. Can you tell me how you adjust the vacuum modulator? I know the hose has to be in good shape but I didn't find anything about how to adjust it.
In case you are interested here is his collection of US vehicles





Soaring

  • Global Moderator
  • *****
  • Posts: 4279
  • Gender: Male
  • 1965 Mustang coupe 289, '03 Mach1, 03 Lariat
  • Mustang: 1965 coupe 289, and 2003 Mach1
  • Daily driver: '03 Ford F-150 Lariat
  • Location: Wimberley, Texas
Re: Automatic transmission shifting at high RPM
« Reply #4 on: April 27, 2008, 04:57:56 PM »
Stock factory modulators are pre-set and most are sealed.  Special built modulators such as TCI StreetFighter modulator-type transmissions are all equipped with adjustable modulators. By turning the adjusting screw (found in the vacuum nipple) counterclockwise, you will lower the spring pre-load. This will cause earlier shifts. By turning the adjusting screw clockwise and raising the spring pre-load, the shift points will go up. The range of adjustability is only a few mph either way.  Now, I doubt seriously this guy has anything but a stock C-4 that is pre-set and sealed.  That's why it is important for us to know exactly what this guy has.  He may have a high stall converter, or he may just have shot converter.  But, the shift points are determined by the converter and how it is set. 

Thierry

  • Administrator
  • *****
  • Posts: 1379
  • Gender: Male
    • Used cars
  • Mustang: Had a 69 Mustang coupe
  • Daily driver: Sunfire
  • Location: Saint John NB Canada
Re: Automatic transmission shifting at high RPM
« Reply #5 on: April 27, 2008, 05:36:21 PM »
 I already asked him if he has the stock converter but he didn't answer, so I guess he doesn't know. He will check his oil filter and vacuum connections tomorrow. Thanks for your suggestions.

Soaring

  • Global Moderator
  • *****
  • Posts: 4279
  • Gender: Male
  • 1965 Mustang coupe 289, '03 Mach1, 03 Lariat
  • Mustang: 1965 coupe 289, and 2003 Mach1
  • Daily driver: '03 Ford F-150 Lariat
  • Location: Wimberley, Texas
Re: Automatic transmission shifting at high RPM
« Reply #6 on: April 28, 2008, 02:04:31 PM »
Let's hope it's just a dirty transmission filter and fluid.  Be sure to tell him to use Type-F transmission fluid.  Most likely he can't get it in France, so will have to order stateside.  Tell him to order 7 or 8 quarts.  That way he will have some for topping off later

Thierry

  • Administrator
  • *****
  • Posts: 1379
  • Gender: Male
    • Used cars
  • Mustang: Had a 69 Mustang coupe
  • Daily driver: Sunfire
  • Location: Saint John NB Canada
Re: Automatic transmission shifting at high RPM
« Reply #7 on: April 28, 2008, 02:06:13 PM »
His transmission is working fine now. The hose for the vacuum modulator was pinched. Now his Mustang won't start because he unplugged the ignition wires and doesn't know in what order they go  ;D. I gave him the solution so he should be fine.Thanks for your help.

Thierry

  • Administrator
  • *****
  • Posts: 1379
  • Gender: Male
    • Used cars
  • Mustang: Had a 69 Mustang coupe
  • Daily driver: Sunfire
  • Location: Saint John NB Canada
Re: Automatic transmission shifting at high RPM
« Reply #8 on: April 28, 2008, 02:09:44 PM »
 Can't he use regular transmission fluid? That's what i used on mine and never had any problem.

Soaring

  • Global Moderator
  • *****
  • Posts: 4279
  • Gender: Male
  • 1965 Mustang coupe 289, '03 Mach1, 03 Lariat
  • Mustang: 1965 coupe 289, and 2003 Mach1
  • Daily driver: '03 Ford F-150 Lariat
  • Location: Wimberley, Texas
Re: Automatic transmission shifting at high RPM
« Reply #9 on: April 28, 2008, 02:32:50 PM »
Can't he use regular transmission fluid? That's what i used on mine and never had any problem.
What do you mean by "regular?"  Type F "is" the regular transmission fluid for a C-4.  If he puts fluid designed for other transmissions he may have problems down the road. If it was my Mustang in France, I would not trust any tranny fluid but Type F.  Read the Mercon type very carefully. Check out this chart.

TRANSMISSION FLUIDS

Over the years, there have been a confusing array of different ATF types and specifications. Make sure the replacement fluid meets or exceeds all OEM requirements. Using the wrong type of fluid may cause transmission problems and damage.

Type F -- Introduced by Ford in 1967 for their automatics. Also used by Toyota.

Type CJ -- Special fluid for Ford C6 transmissions. Similar to Dexron II. Must not be used in automatics that require Type F. Can be replaced with Mercon or Mercon V.

Type H -- Another limited Ford spec that differs from both Dexron and

Mercon -- Ford fluid introduced in 1987, very similar to Dexron II. Okay for all earlier Fords except those that require Type F. As of July 1, 2007, the production and licensing of Mercon ATF by Ford ends. Ford says applications that require Mercon ATF can now be serviced with Mercon V.

Mercon V -- Ford's newest type, introduced in 1997 for Ranger, Explorer V6 and Aerostar, and 1998 & up Windstar, Taurus/Sable and Continental. This is the current ATF for all late model Ford products.

Dexron -- General Motors original ATF for automatics.

Dexron II -- Improved GM formula with better viscosity control and additional oxidation inhibitors. Can be used in place of Dexron.

Dexron IIE -- GM fluid for electronic transmissions.

Dexron III -- Replaces Dexron IIE and adds improved oxidation and corrosion control in GM electronic automatics.

Dexron III (H) -- Improved version of Dexron III released in 2003.

Dexron III/Saturn -- A special fluid spec for Saturns.

Dexron-VI -- For 2006 GM Hydra-Matic 6L80 6-speed rear-wheel-drive transmissions, can also be used in 2005 transmissions that require Dexron III but is NOT recommended for older transmissions or Saturn VUE transmissions.

Chrysler 7176 -- For Chrysler FWD transaxles.

Chrysler 7176D (ATF+2) -- Adds improved cold temperature flow and oxidation resistance. Introduced 1997.

Chrysler 7176E (ATF+3) -- Adds improved shear stability and uses a higher quality base oil. Required for four-speed automatics (do NOT use Dexron or Mercon as a substitute).

Chrysler ATF+4 (ATE) -- Introduced in 1998, ATF+4 is synthetic and replaces the previous ATF+3 fluid. Used primarily for 2000 and 2001 vehicles, it can also be used in earlier Chrysler transmissions (except 1999 and older minivans with 41TE/AE transmission). ATF+3 should continue to be used for 1999 and earlier minivans because of the potential for torque converter shudder during break in.

NOTE:Chrysler ATF+4 Must always be used in vehicles that were originally filled with ATF+4. The red dye used in ATF+4 is not permanent. As the fluid ages it may become darker or appear brown in color. ATF+4 also has a unique odor that may change with age. Therefore, do not relay on the color and odor of ATF+4 to determine if the fluid needs to be changed. Follow the OEM recommended service interval.

Chrysler ATF+5 for 2002 and newer models.

IMPORT APPLICATIONS:

BMW LT7114l or LA2634 -- Special formula for BMW transmissions.

Genuine Honda ZL ATF -- Special ATF for Honda automatics (except CVT applications).

Mitsubishi Diamond SP-II & SP-Ill -- Special formula ATFs for Mitsubishi transmissions.

Nissan J-Matic -- Special formula for Nissan transmissions.

Toyota Type T, T-III & T-IV -- Special formula ATFs for Toyota and Lexus transmissions.

NOTE: There are a number of aftermarket synthetic ATF fluids that claim to meet numerous OEM requirements. Refer to the product label for approved applications.


rmodel65

  • Global Moderator
  • *****
  • Posts: 681
  • Gender: Male
  • the mustang man
  • Mustang: 65 fastback modded
  • Daily driver: 1991 gt vert
  • Location: US
Re: Automatic transmission shifting at high RPM
« Reply #10 on: May 05, 2008, 01:52:12 AM »
yeah the friction modifiers are different in type f fluid, unless its been rebuilt with parts that specified otherwise. even when i rebuilt my tranny with a tci kit it still specified type f fluid

Thierry

  • Administrator
  • *****
  • Posts: 1379
  • Gender: Male
    • Used cars
  • Mustang: Had a 69 Mustang coupe
  • Daily driver: Sunfire
  • Location: Saint John NB Canada
Re: Automatic transmission shifting at high RPM
« Reply #11 on: May 05, 2008, 09:01:15 AM »
 I worked in a Ford plant that builds automatic transmissions for Mustangs and trucks and I used their Mercon fluid for my 69 Mustang during 5 years ::) I am happy to know the transmission is still going strong from what the actual owner tells me  ;D

Soaring

  • Global Moderator
  • *****
  • Posts: 4279
  • Gender: Male
  • 1965 Mustang coupe 289, '03 Mach1, 03 Lariat
  • Mustang: 1965 coupe 289, and 2003 Mach1
  • Daily driver: '03 Ford F-150 Lariat
  • Location: Wimberley, Texas
Re: Automatic transmission shifting at high RPM
« Reply #12 on: May 10, 2008, 02:48:56 PM »
Then, you were just lucky.  Mercon is absolutely not good for an early Ford automatic transmission such as a C-4,  and Dexron is for GM trannies. 

rmodel65

  • Global Moderator
  • *****
  • Posts: 681
  • Gender: Male
  • the mustang man
  • Mustang: 65 fastback modded
  • Daily driver: 1991 gt vert
  • Location: US
Re: Automatic transmission shifting at high RPM
« Reply #13 on: May 11, 2008, 05:46:05 AM »
yeah the dexron is for the newer stuff but c4 from the 60 and 70 etc used type "F"

normally it states the exact type on the dipstick

Soaring

  • Global Moderator
  • *****
  • Posts: 4279
  • Gender: Male
  • 1965 Mustang coupe 289, '03 Mach1, 03 Lariat
  • Mustang: 1965 coupe 289, and 2003 Mach1
  • Daily driver: '03 Ford F-150 Lariat
  • Location: Wimberley, Texas
Re: Automatic transmission shifting at high RPM
« Reply #14 on: May 12, 2008, 06:43:52 PM »
I'm not sure of the exact definition, but all ATF's are friction modified, whereas Type F is not.  Again, if I were giving advice to someone with a C-4 I would advise them to use Type F in their transmission, and change it every 30,000 miles or so. 

Jeff1967

  • Photo contest winner
  • *
  • Posts: 282
  • Mustang: 1967 convertible
  • Daily driver: 2011 Chev Silverado Dura Max 4X4
  • Location: Bend, Oregon
Re: Automatic transmission shifting at high RPM
« Reply #15 on: August 06, 2011, 05:30:12 PM »
Those instructions look accurate, although it is a good idea to inspect the lip of the pan to make sure it is
straight and flat especially around the bolt holes. Sometimes they are over tightened which can cause the areas around the bolt holes to become high points that can cause leaks. I also take a little steel wool or light paper to that surface as to make sure it is nice and clean before putting the gasket on then bolting into place.

Been there done that

Jeff

 

+-Navigation

Other languages
ESPANOL
FRANCAIS
Soaring
Soaring
In memory of our moderator Glen Wren AKA Soaring
1943-2011
Links



Dallas Mustang


Menu
LO-FI Version
Mustang classifieds
Muscle car classifieds
Classic Mustang FAQ


Mustangs for sale


Top Posters

Soaring
Posts: 4279
Thierry
Posts: 1379
66GTKFB
Posts: 845
rmodel65
Posts: 681
Jeff73Mach1
Posts: 471

Used Cars for sale - Ford Mustang classifieds - Forum Camaro FR

Powered by EzPortal