2008 GT Automatic Transmission Issues
03-02-2021, 12:44 PM
#12
Gentleman's Relish
Join Date: Feb 2005
Location: AZ
Posts: 13,090
03-02-2021, 12:55 PM
#13
Gentleman's Relish
Join Date: Feb 2005
Location: AZ
Posts: 13,090
Thank you so much derf00 for all the information and all the links. I will start with the basics. Filter and fluid. I am considering fixing the reverse servo, since I will take the pan off during the fluid change.
About the forward issie, I don’t know in what gear it happens, but typically after about 10 minutes of driving and usually at about 30 mph. It does not slam when it engages again. Usually I just slow way down, which seems to make it down shift smoothly and then it will **** up again smoothly and no issues after that. I have not had this happen twice in a row on the same trip. Only once per trip.
About the forward issie, I don’t know in what gear it happens, but typically after about 10 minutes of driving and usually at about 30 mph. It does not slam when it engages again. Usually I just slow way down, which seems to make it down shift smoothly and then it will **** up again smoothly and no issues after that. I have not had this happen twice in a row on the same trip. Only once per trip.
If you're only getting an occasional issue with the shifting, then the fluid and filter may be all it needs.
When you drain your fluid, check the color. Red, a little red, brown, or black? Also check the fluid and pan for a glittery look. A little is ok but if it looks like a Twilight vampire standing in the sun light or your clothes after a night out at the strip clubs, you got mechanical problems waiting to happen.
03-10-2021, 12:38 PM
#15
Gentleman's Relish
Join Date: Feb 2005
Location: AZ
Posts: 13,090
Is it rebuilt or remanufactured? There is a difference.
Rebuilt only replaces parts that are worn out-of-spec like clutch disks. Remanufactured will replace all wear items and also address some of the problems like the bore wear for the intermediate and overdrive bores of the transmission housing.
That being said, even remaned can have issues. My LKQ remanned transmission failed internally on year two of it's three year warranty. Was replaced at no charge by the dealer that installed it. Just after year 3, it started having issues again.. Luckily it was only the solenoid pack so, I replaced the aftermarket solenoid pack with a BOSCH OEM one and haven't had any issues since then. (nine months now.).
Rebuilt only replaces parts that are worn out-of-spec like clutch disks. Remanufactured will replace all wear items and also address some of the problems like the bore wear for the intermediate and overdrive bores of the transmission housing.
That being said, even remaned can have issues. My LKQ remanned transmission failed internally on year two of it's three year warranty. Was replaced at no charge by the dealer that installed it. Just after year 3, it started having issues again.. Luckily it was only the solenoid pack so, I replaced the aftermarket solenoid pack with a BOSCH OEM one and haven't had any issues since then. (nine months now.).
03-15-2021, 01:53 PM
#17
Gentleman's Relish
Join Date: Feb 2005
Location: AZ
Posts: 13,090
let us know how it goes after you drain/refill the fluid, change the filter and clean the reverse servo.
04-19-2021, 08:36 AM
#18
Thread Starter
Join Date: Feb 2021
Location: CA
Posts: 11
I finally got to work on my Mustang...
Drained and refilled the transmission 5 times. 4-5 qts at a time. Ran the transmission through all the gears for about 10 minutes between each drain/refill. Then dropped the transmission pan, replaced the reverse servo piston and O-ring, and replaced the filter. The fluid from the first drain was very dark. It got better and better after each drain/refill and look good after the last drain. When I dropped the pan, there was some grime on the magnet ring, about 1/8" thick, and a thin film of grime on the pan in some locations. It did not seem bad to me. The reverse servo was clean.
After putting it all back together, I test drove the car several times. Unfortunately, the symptoms are still there. When shifting into reverse, it hesitates, the slams into gear. When driving at about 30mph, it shifts out of gear and revs up the rpm until I slow down and it will shift back into a lower gear. I can also manually **** it into 3rd and it will drive in 3rd. When I shift it back to D it will go back out of gear unless I have slowed down so it can shift into a lower gear. It shifts out of gear when it is trying to shift up from 3rd to 4th.
Rather than spending more on this transmission, I am leaning towards looking for a rebuilt transmission.
Drained and refilled the transmission 5 times. 4-5 qts at a time. Ran the transmission through all the gears for about 10 minutes between each drain/refill. Then dropped the transmission pan, replaced the reverse servo piston and O-ring, and replaced the filter. The fluid from the first drain was very dark. It got better and better after each drain/refill and look good after the last drain. When I dropped the pan, there was some grime on the magnet ring, about 1/8" thick, and a thin film of grime on the pan in some locations. It did not seem bad to me. The reverse servo was clean.
After putting it all back together, I test drove the car several times. Unfortunately, the symptoms are still there. When shifting into reverse, it hesitates, the slams into gear. When driving at about 30mph, it shifts out of gear and revs up the rpm until I slow down and it will shift back into a lower gear. I can also manually **** it into 3rd and it will drive in 3rd. When I shift it back to D it will go back out of gear unless I have slowed down so it can shift into a lower gear. It shifts out of gear when it is trying to shift up from 3rd to 4th.
Rather than spending more on this transmission, I am leaning towards looking for a rebuilt transmission.
04-19-2021, 01:36 PM
#19
Gentleman's Relish
Join Date: Feb 2005
Location: AZ
Posts: 13,090
The grime on the magnet is normal. Its liner dust from the clutches/bands from normal wear. it's like the brake dust you get from your brakes over time as the linings wear.
How many quarts of trans fluid did it take when you refilled it after you dropped the pan and replaced the filter and reverse servo? How did you check the level? It should've taken ~7.5-8 quarts
if the fluid level is correct:
yes, it does seem a new trans is the direction you're headed.
Could be valve body wear, solenoid pack failure, and/or servo bore wear. Solenoid pack failures will usually throw a code by blinking the O/D Off light on the days or turning the light on solid (like a Check engine light). For that reason I will focus on the mechanical only below.
For Reverse - most likely the valve body has an issue.
For the 2-3 shifting issue it sounds like the intermediate servo since it will hold the gear when you manually select it. Either the servo itself (rubber seal just like the reverse servo) is worn or the aluminum bore on the transmission housing is worn. If it's a bore issue, it's best to get a remanufactured transmission. The cost to ream and sleeve a bore vs just swapping the whole trans is about the same. To ream and sleeve the bore requires removal of the trans and pretty much a tear-down to get the room to do the job without contaminating the rest of the trans with metal shavings, then you rebuild of your existing trans.
Intermediate and Overdrive bore wear can also contribute to the 3-4 shift issue.
BTW. if you want to manually shift from 3-4 you can press the O/D button on the shifter and the O/D Off light will show up on the dash. This electronically turns off 5th gear. Now when you shift from 3 to D, as long as you are in the right RPM range, it should force it into 4th until you drop your speed for it to drop back into 3rd or 2nd, or 1st.
How many quarts of trans fluid did it take when you refilled it after you dropped the pan and replaced the filter and reverse servo? How did you check the level? It should've taken ~7.5-8 quarts
if the fluid level is correct:
yes, it does seem a new trans is the direction you're headed.
Could be valve body wear, solenoid pack failure, and/or servo bore wear. Solenoid pack failures will usually throw a code by blinking the O/D Off light on the days or turning the light on solid (like a Check engine light). For that reason I will focus on the mechanical only below.
For Reverse - most likely the valve body has an issue.
For the 2-3 shifting issue it sounds like the intermediate servo since it will hold the gear when you manually select it. Either the servo itself (rubber seal just like the reverse servo) is worn or the aluminum bore on the transmission housing is worn. If it's a bore issue, it's best to get a remanufactured transmission. The cost to ream and sleeve a bore vs just swapping the whole trans is about the same. To ream and sleeve the bore requires removal of the trans and pretty much a tear-down to get the room to do the job without contaminating the rest of the trans with metal shavings, then you rebuild of your existing trans.
Intermediate and Overdrive bore wear can also contribute to the 3-4 shift issue.
BTW. if you want to manually shift from 3-4 you can press the O/D button on the shifter and the O/D Off light will show up on the dash. This electronically turns off 5th gear. Now when you shift from 3 to D, as long as you are in the right RPM range, it should force it into 4th until you drop your speed for it to drop back into 3rd or 2nd, or 1st.
04-21-2021, 06:50 AM
#20
5th Gear Member
Join Date: Sep 2010
Location: IN
Posts: 2,248
I finally got to work on my Mustang...
Drained and refilled the transmission 5 times. 4-5 qts at a time. Ran the transmission through all the gears for about 10 minutes between each drain/refill. Then dropped the transmission pan, replaced the reverse servo piston and O-ring, and replaced the filter. The fluid from the first drain was very dark. It got better and better after each drain/refill and look good after the last drain. When I dropped the pan, there was some grime on the magnet ring, about 1/8" thick, and a thin film of grime on the pan in some locations. It did not seem bad to me. The reverse servo was clean.
After putting it all back together, I test drove the car several times. Unfortunately, the symptoms are still there. When shifting into reverse, it hesitates, the slams into gear. When driving at about 30mph, it shifts out of gear and revs up the rpm until I slow down and it will shift back into a lower gear. I can also manually **** it into 3rd and it will drive in 3rd. When I shift it back to D it will go back out of gear unless I have slowed down so it can shift into a lower gear. It shifts out of gear when it is trying to shift up from 3rd to 4th.
Rather than spending more on this transmission, I am leaning towards looking for a rebuilt transmission.
Drained and refilled the transmission 5 times. 4-5 qts at a time. Ran the transmission through all the gears for about 10 minutes between each drain/refill. Then dropped the transmission pan, replaced the reverse servo piston and O-ring, and replaced the filter. The fluid from the first drain was very dark. It got better and better after each drain/refill and look good after the last drain. When I dropped the pan, there was some grime on the magnet ring, about 1/8" thick, and a thin film of grime on the pan in some locations. It did not seem bad to me. The reverse servo was clean.
After putting it all back together, I test drove the car several times. Unfortunately, the symptoms are still there. When shifting into reverse, it hesitates, the slams into gear. When driving at about 30mph, it shifts out of gear and revs up the rpm until I slow down and it will shift back into a lower gear. I can also manually **** it into 3rd and it will drive in 3rd. When I shift it back to D it will go back out of gear unless I have slowed down so it can shift into a lower gear. It shifts out of gear when it is trying to shift up from 3rd to 4th.
Rather than spending more on this transmission, I am leaning towards looking for a rebuilt transmission.