I have a 1987, 5.0 liter (302 c.i.), 4X4 full-sized Bronco that very
recently has developed an AOD transmission problem. The problem is
this.
When I'm driving in *either* of the two Drive gears - overdrive-D (or)
regular-D, it won't shift into 3rd gear (unless I've just started
driving and the tranny is relatively cool). Also, when the tranny is
refusing to shift into 3rd, but I keep going a little faster, PAST the
point where it should've shifted into 3rd, then I slightly let off on
the accelerator, then press down on accelerator, I find that the tranny
has shifted into neutral. I then have to wait until I slow down
enough for it to downshift back into 2nd (or sometimes 1st) in order to
get out of neutral.
I know very little about automatic transmissions, so I found THIS site
and forum and have learned quite a bit after reading many pages of
posts. I also went to the HowStuffWorks.com site and learned even
more, BUT, I still have a number of questions that I hope some of you
will have the time to answer. Your effort WILL be appreciated.
This forum told me that my tranny is NOT computer (electronically)
controlled, but instead, was "line pressure" controlled from the
throttle body. The HowStuffWorks site went into a little more detail
and said that my tranny would be controlled by EITHER:
A) a "cable linkage" FROM the (didn't say, but I'm assuming
throttle body) TO the tranny's "throttle valve".
(or)
B) a "vacuum modulator" FROM the (didn't say, but I'm assuming
manifold) TO the tranny's "throttle valve".
So, my first 4 questions are:
1) Which of the above definitely controls MY tranny?
2) Whichever one it is above, is my ""FROM the"" assumption
correct?
3) If it's "B" above, is the "vacuum modulator" (or the path to the
V.M.) a rubber hose, (or) is it metal tubing?
4) If one of the above IS the problem, can *either* one be fixed
WITHOUT removing and opening up the transmission?
A number of transmission repair shops mention a Transmission Diagnostic
Test. I assume that with a computer-controlled tranny, doing a
computer diagnostic could tell you quite a bit about what's going on
inside the tranny, BUT, I would think that with a NON-computer tranny, a
diagostic test would give you very little really helpful info.
So, my next 2 questions are:
5) What are the things a mechanic DOES check during a non-computer
transmission diagnostic test?
6) How much should this test cost me (if the shop doesn't offer it
for free)?
From all of the info I've learned so far, I can only speculate that,
unfortunately, there are a number of things that could be causing my
tranny problem.
Below, I'm repeating the symptoms to my problem that I mentioned at the
beginning of this post. Right after that, I listed some things that
MIGHT be the problem. I would really be interested in your educated
guess as to which one of those is "most likely" my problem.
""When I'm driving in *either* of the two Drive gears - overdrive-D (or)
regular-D, it won't shift into 3rd gear (unless I've just started
driving and the tranny is relatively cool). Also, when the tranny is
refusing to shift into 3rd, but I keep going a little faster, PAST the
point where it should've shifted into 3rd, then I slightly let off on
the accelerator, then press down on accelerator, the tranny will go into
neutral. I then have to wait until I slow down enough for it to
downshift back into 2nd (or sometimes 1st) in order to get out of
neutral.""
Other facts about my transmission:
*** overall, this tranny has had an "easy life".
*** has virtually never towed anything
*** has never been off-road hill (or) rock climbing
*** has had the transmission fluid changed on a regular basis (and) the
current fluid is a nice, bright red color.
*** has never been in a flood
*** is the original tranny, but was overhauled at 95,000 miles for NO
particular reason except that my Dad must have thought a tranny wouldn't
last much over 100,000 miles and didn't want to get stranded way out in
west Texas on one of his hunts. This overhauled tranny has 163,000
miles on it.
7) Which one of the following do YOU think is "most likely" my
problem.
*** The "Cable Linkage" (or) "Vacuum Modulator" is defective,
therefore not giving the tranny the correct engine speed or "load" for
it to be able to shift gears properly.
*** Some of the "Bands" and/or "Clutch Plates" are worn out.
*** The "2-to-3 Shift Valve" is defective and not supplying enough
hydraulic pressure to the bands / clutches.
*** The "Governor" and/or "Throttle Valve" is defective and not
supplying enough tranny fluid pressure to the "2-to-3 Shift Valve".
*** The "Pump" is defective and not supplying enough tranny fluid
to the entire transmission - however, if this were the case, I think I'd
be having other shifting problems.
Two final questions.....
The last time I had the transmission serviced, which was at a Ford
dealership, they did it the "new" way by forcing new fluid into the
tranny and having it "flush out" the old fluid. Unfortunately, by
doing it this way, the filter isn't replaced and the pan isn't checked
for metal particles.
8) What is your opinion of this type of servicing - is it any good
at all?
9) Also, what are the chances a clogged filter could be causing my
problem? Remember though, the problem occurs during only ONE phase of
automatic shifting - from 2nd to 3rd.
Thanks for reading this long post. I'm really looking forward to your
answers.
Bill
recently has developed an AOD transmission problem. The problem is
this.
When I'm driving in *either* of the two Drive gears - overdrive-D (or)
regular-D, it won't shift into 3rd gear (unless I've just started
driving and the tranny is relatively cool). Also, when the tranny is
refusing to shift into 3rd, but I keep going a little faster, PAST the
point where it should've shifted into 3rd, then I slightly let off on
the accelerator, then press down on accelerator, I find that the tranny
has shifted into neutral. I then have to wait until I slow down
enough for it to downshift back into 2nd (or sometimes 1st) in order to
get out of neutral.
I know very little about automatic transmissions, so I found THIS site
and forum and have learned quite a bit after reading many pages of
posts. I also went to the HowStuffWorks.com site and learned even
more, BUT, I still have a number of questions that I hope some of you
will have the time to answer. Your effort WILL be appreciated.
This forum told me that my tranny is NOT computer (electronically)
controlled, but instead, was "line pressure" controlled from the
throttle body. The HowStuffWorks site went into a little more detail
and said that my tranny would be controlled by EITHER:
A) a "cable linkage" FROM the (didn't say, but I'm assuming
throttle body) TO the tranny's "throttle valve".
(or)
B) a "vacuum modulator" FROM the (didn't say, but I'm assuming
manifold) TO the tranny's "throttle valve".
So, my first 4 questions are:
1) Which of the above definitely controls MY tranny?
2) Whichever one it is above, is my ""FROM the"" assumption
correct?
3) If it's "B" above, is the "vacuum modulator" (or the path to the
V.M.) a rubber hose, (or) is it metal tubing?
4) If one of the above IS the problem, can *either* one be fixed
WITHOUT removing and opening up the transmission?
A number of transmission repair shops mention a Transmission Diagnostic
Test. I assume that with a computer-controlled tranny, doing a
computer diagnostic could tell you quite a bit about what's going on
inside the tranny, BUT, I would think that with a NON-computer tranny, a
diagostic test would give you very little really helpful info.
So, my next 2 questions are:
5) What are the things a mechanic DOES check during a non-computer
transmission diagnostic test?
6) How much should this test cost me (if the shop doesn't offer it
for free)?
From all of the info I've learned so far, I can only speculate that,
unfortunately, there are a number of things that could be causing my
tranny problem.
Below, I'm repeating the symptoms to my problem that I mentioned at the
beginning of this post. Right after that, I listed some things that
MIGHT be the problem. I would really be interested in your educated
guess as to which one of those is "most likely" my problem.
""When I'm driving in *either* of the two Drive gears - overdrive-D (or)
regular-D, it won't shift into 3rd gear (unless I've just started
driving and the tranny is relatively cool). Also, when the tranny is
refusing to shift into 3rd, but I keep going a little faster, PAST the
point where it should've shifted into 3rd, then I slightly let off on
the accelerator, then press down on accelerator, the tranny will go into
neutral. I then have to wait until I slow down enough for it to
downshift back into 2nd (or sometimes 1st) in order to get out of
neutral.""
Other facts about my transmission:
*** overall, this tranny has had an "easy life".
*** has virtually never towed anything
*** has never been off-road hill (or) rock climbing
*** has had the transmission fluid changed on a regular basis (and) the
current fluid is a nice, bright red color.
*** has never been in a flood
*** is the original tranny, but was overhauled at 95,000 miles for NO
particular reason except that my Dad must have thought a tranny wouldn't
last much over 100,000 miles and didn't want to get stranded way out in
west Texas on one of his hunts. This overhauled tranny has 163,000
miles on it.
7) Which one of the following do YOU think is "most likely" my
problem.
*** The "Cable Linkage" (or) "Vacuum Modulator" is defective,
therefore not giving the tranny the correct engine speed or "load" for
it to be able to shift gears properly.
*** Some of the "Bands" and/or "Clutch Plates" are worn out.
*** The "2-to-3 Shift Valve" is defective and not supplying enough
hydraulic pressure to the bands / clutches.
*** The "Governor" and/or "Throttle Valve" is defective and not
supplying enough tranny fluid pressure to the "2-to-3 Shift Valve".
*** The "Pump" is defective and not supplying enough tranny fluid
to the entire transmission - however, if this were the case, I think I'd
be having other shifting problems.
Two final questions.....
The last time I had the transmission serviced, which was at a Ford
dealership, they did it the "new" way by forcing new fluid into the
tranny and having it "flush out" the old fluid. Unfortunately, by
doing it this way, the filter isn't replaced and the pan isn't checked
for metal particles.
8) What is your opinion of this type of servicing - is it any good
at all?
9) Also, what are the chances a clogged filter could be causing my
problem? Remember though, the problem occurs during only ONE phase of
automatic shifting - from 2nd to 3rd.
Thanks for reading this long post. I'm really looking forward to your
answers.
Bill
- hey I'm new at all of this transmission stuff! :blush: If so (or not), tell me more.
