1993 FZJ80 Transmission slips in forward gears
- Thread starter spdwaver
- Start date
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CRAP!! This has happened to me twice now and the common denominator was that I was parked on a slight uphill grade here at my work. I get in at home and drive to work with no problem then I get back in 30 minutes later to drive to the dealer (only two times I drove it to work) and I had that problem. I would then put it in L and it would take off with no problem.
Pardon my ignorance but what do the Shift solenoids do for a living inside the tranny? I am trying to justify forkin up that coin to replace them. Are they inside or outside the tranny? Dan, it looks like I may be calling you in the near future for yet another order.
Pardon my ignorance but what do the Shift solenoids do for a living inside the tranny? I am trying to justify forkin up that coin to replace them. Are they inside or outside the tranny? Dan, it looks like I may be calling you in the near future for yet another order.
Is your "D" indicator working when problem occurs? I've '93 HDJ80 with electronic shift control and sometimes experience the same symptoms, usually if I put shifter somewhere in between N-D or D-2. Gear selector position switch doesn't inform ECU about D selected, no solenoids engaged and this causes 3rd gear. Light tap on the shifter and everything gets back to norm.
Could it be faulty (dirty?) gear selector switch in your case?
Could it be faulty (dirty?) gear selector switch in your case?
Honestly, when this happened and my heart skipped a few beats and I looked around for the AED I had not noticed the status of the D indicator light. I will keep an eye out and hopefully this does not happen again.
I have noticed that my shifter is weird and perhaps I need to do the adjust on "the" cable (I need to search and find the thread for this).
I have noticed that my shifter is weird and perhaps I need to do the adjust on "the" cable (I need to search and find the thread for this).
spdwaver
Formerly Kalifornistanian
- Thread starter
- #46
Apparently there is a way to check the operation of the solenoids.
From the FSM:
2. INSPECT SOLENOID
(a) Disconnect the connector from TCM.
(b) Measure the resistance between S1, S2, SL, ST and
ground.
Resistance:
11−15 ohm
(c) Apply battery voltage to each terminal. Check that an operation noise can be heard from the solenoid.
3. CHECK SOLENOID SEALS
If there is foreign material in the solenoid valve, there will be no fluid control even with solenoid operation.
(a) Check No. 1, No. 2 and timing solenoid valves.
• Check that the solenoid valves do not leak when low−pressure compressed air is applied.
• When supply battery voltage to the solenoids, check that the solenoid valves open.
(b) Check the lock−up solenoid valve.
• Apply 490 kPa (5 kgf/cm2, 71 psi) of compressed air, check that the solenoid valve opens.
• When supply battery voltage to the solenoid, check that the solenoid valve does not leak the
air.
If malfunction is found during voltage inspection (step1.), inspect the components listed below.
I wonder if there could be debris in the solenoid, hindering it's operation. This seems logical given the fact that lack of proper operation is intermittent.
I will perform these checks tomorrow. Has anyone else performed the same operation with some insight into this?
From the FSM:
2. INSPECT SOLENOID
(a) Disconnect the connector from TCM.
(b) Measure the resistance between S1, S2, SL, ST and
ground.
Resistance:
11−15 ohm
(c) Apply battery voltage to each terminal. Check that an operation noise can be heard from the solenoid.
3. CHECK SOLENOID SEALS
If there is foreign material in the solenoid valve, there will be no fluid control even with solenoid operation.
(a) Check No. 1, No. 2 and timing solenoid valves.
• Check that the solenoid valves do not leak when low−pressure compressed air is applied.
• When supply battery voltage to the solenoids, check that the solenoid valves open.
(b) Check the lock−up solenoid valve.
• Apply 490 kPa (5 kgf/cm2, 71 psi) of compressed air, check that the solenoid valve opens.
• When supply battery voltage to the solenoid, check that the solenoid valve does not leak the
air.
If malfunction is found during voltage inspection (step1.), inspect the components listed below.
I wonder if there could be debris in the solenoid, hindering it's operation. This seems logical given the fact that lack of proper operation is intermittent.
I will perform these checks tomorrow. Has anyone else performed the same operation with some insight into this?
spdwaver
Formerly Kalifornistanian
- Thread starter
- #47
I decided to drop the pan to investigate the state of the solenoids.
First, I cleaned the pan so that debris will not drop into the fluid. I plan on reusing the fluid since it just got changed out less than two weeks ago.
I drained the fluid into a five-gallon bucket. Having a lift makes this jog a lot easier, with plenty of room to work.
Then, I removed the shield (I should have removed this first, but live and learn, as they say.
After cleaning the pan bolts, they were removed.
Tip: Before lowering the pan, clean off the outside of the dip stick tube; this will reduce the amount of dirt that can fall into the pan, which can otherwise lead you to believe you have particles in the bottom of the pan.
But first, my three year-old needed to remove the mud flaps, so she did.
Second pic shows the oil draining into the bucket.
In the third pic I have highlighted the filler tube in green; clean this prior to pulling the pan.
First, I cleaned the pan so that debris will not drop into the fluid. I plan on reusing the fluid since it just got changed out less than two weeks ago.
I drained the fluid into a five-gallon bucket. Having a lift makes this jog a lot easier, with plenty of room to work.
Then, I removed the shield (I should have removed this first, but live and learn, as they say.
After cleaning the pan bolts, they were removed.
Tip: Before lowering the pan, clean off the outside of the dip stick tube; this will reduce the amount of dirt that can fall into the pan, which can otherwise lead you to believe you have particles in the bottom of the pan.But first, my three year-old needed to remove the mud flaps, so she did.
Second pic shows the oil draining into the bucket.
In the third pic I have highlighted the filler tube in green; clean this prior to pulling the pan.
spdwaver
Formerly Kalifornistanian
- Thread starter
- #48
As soon as I dropped the pan, I had a clear view of the valve body, where the solenoids are located.
Could someone verify the two solenoids that are in reference? I marked the first two red, and blue in another angle.
The pan appeared to be really clean, and the magnets had a very minimal amount of very fine dark material stuck to them. The layer present was less than 1mm thick.
Could someone verify the two solenoids that are in reference? I marked the first two red, and blue in another angle.
The pan appeared to be really clean, and the magnets had a very minimal amount of very fine dark material stuck to them. The layer present was less than 1mm thick.
orangefj45
Supporting Vendor
a few thoughts......
did this problem exist when you bought the truck? did the seller mention it? why was the trans fluid changed right before you got it? who did it? why was it low? .......
then some more: you should never shift your transmission into any other gear when you're waiting at a light. i know the old wife's tail about using more fuel and whatnot. it's a bunch of bs. the torque converter in your transmission is designed to allow you to sit still while in gear. you're not doing any harm by leaving it in gear. actually, you're doing more harm by shifting it into neutral and then back into gear when you're ready to go. why you ask? well, everytime an automatic transmission shifts, it either engages a clutch pack or a band by applying hydraulic pressure via the valve body ( and on late model transmissions, via sending current to a shift solenoid ). just like any other friction material ( like a standard clutch ), everytime you engage said material, you generate heat due to friction and you cause a tiny bit of wear on the friction material. repeat this and over time, you can cause significant extra wear which in turn will cause the transmission to require work sooner than it should.
so just leave it in gear at the stop light............
as for shift solenoids, they typically either work or they do not. however, they can slowly plug up with foreign material. a shift solenoid is basically an electrical coil with a ball valve in the middle. send current thru the coil and it generates a magnetic field. this in turn causes the ball to travel towards the magnetic field. depending on the style of the solenoid, this can either open or close a passage, used to control fluid flow in an automatic transmission.
since the coil becomes a magnet, it can't differentiate between items it attracts. so it'll suck in the check-ball and other metal objects it can attract. that includes small metal particles suspended in the transmission fluid. pretty much the same stuff you found on your pan magnet. see where i'm going with this? the inside of the solenoids commonly gets clogged up with this fine metal and cancause the solenoids to stick. oftentimes they're more likely to do so when the transmission has some miles on it and when it's cold. clearances are tighter and things get stuck easier.
but late model autos are'nt just controlled by the solenoids themselves. the solenoids receive a signal via the wiring harness thru the ecm. the computer needs input from a number of sensors to determine what to do and when to shift. if the computer does not have enough input, it may not send the "proper" signal. so you could have a problem with your MLPS switch, vss or toehr sensors.
then we get to "the cable". this is called a TV cable. short for Trottle Valve cable. it's responsible for shift timing and firmess. the later the transmissionshifts, the firmer it shifts. all of this is a function of the throttle valve itself. adjusting the cable essentially adjusts the valves' position relative to the bore it resides in. this valve can also be the cluprit. it's a common issue in th700 transmissions. the clearances for this valve and it's bore are extremely tight so no fluid can bleed by. if any foreignmaterial ( like a small piece of clutch material or a metal fragment ) gets stuck between the bore and valve, it can and will cause the valve to hang up. that in turn will affect shift timing, firmness as well as downshifting. so it could be the culprit.
here's what i would do: first off, have a professional shop put a scanner on the truck and run a diagnostic test. if any of the solenoids have an issu ( even intermitten ), then the computer will remember it and bring it to the scanners' attention via a "memory code". if the scan yields no codes, then you can pretty much rule out the solenoids.
do as much homework and diagnostic work before "throwing parts at the problem" or tearing into the rig. at this point, it could be a transmission problem, either electgrical or mechanical. it could also be a non-transmission ralated issue, like the drive flange mentioned earlier.
hth
georg @ valley hybrids
ps: i believe rostra makes aftermarket solenoinds for the 440 and 442. if so, then i can get them for a good price for you. if not, then you're limited to good used or brand new oem units.
did this problem exist when you bought the truck? did the seller mention it? why was the trans fluid changed right before you got it? who did it? why was it low? .......
then some more: you should never shift your transmission into any other gear when you're waiting at a light. i know the old wife's tail about using more fuel and whatnot. it's a bunch of bs. the torque converter in your transmission is designed to allow you to sit still while in gear. you're not doing any harm by leaving it in gear. actually, you're doing more harm by shifting it into neutral and then back into gear when you're ready to go. why you ask? well, everytime an automatic transmission shifts, it either engages a clutch pack or a band by applying hydraulic pressure via the valve body ( and on late model transmissions, via sending current to a shift solenoid ). just like any other friction material ( like a standard clutch ), everytime you engage said material, you generate heat due to friction and you cause a tiny bit of wear on the friction material. repeat this and over time, you can cause significant extra wear which in turn will cause the transmission to require work sooner than it should.
so just leave it in gear at the stop light............
as for shift solenoids, they typically either work or they do not. however, they can slowly plug up with foreign material. a shift solenoid is basically an electrical coil with a ball valve in the middle. send current thru the coil and it generates a magnetic field. this in turn causes the ball to travel towards the magnetic field. depending on the style of the solenoid, this can either open or close a passage, used to control fluid flow in an automatic transmission.
since the coil becomes a magnet, it can't differentiate between items it attracts. so it'll suck in the check-ball and other metal objects it can attract. that includes small metal particles suspended in the transmission fluid. pretty much the same stuff you found on your pan magnet. see where i'm going with this? the inside of the solenoids commonly gets clogged up with this fine metal and cancause the solenoids to stick. oftentimes they're more likely to do so when the transmission has some miles on it and when it's cold. clearances are tighter and things get stuck easier.
but late model autos are'nt just controlled by the solenoids themselves. the solenoids receive a signal via the wiring harness thru the ecm. the computer needs input from a number of sensors to determine what to do and when to shift. if the computer does not have enough input, it may not send the "proper" signal. so you could have a problem with your MLPS switch, vss or toehr sensors.
then we get to "the cable". this is called a TV cable. short for Trottle Valve cable. it's responsible for shift timing and firmess. the later the transmissionshifts, the firmer it shifts. all of this is a function of the throttle valve itself. adjusting the cable essentially adjusts the valves' position relative to the bore it resides in. this valve can also be the cluprit. it's a common issue in th700 transmissions. the clearances for this valve and it's bore are extremely tight so no fluid can bleed by. if any foreignmaterial ( like a small piece of clutch material or a metal fragment ) gets stuck between the bore and valve, it can and will cause the valve to hang up. that in turn will affect shift timing, firmness as well as downshifting. so it could be the culprit.
here's what i would do: first off, have a professional shop put a scanner on the truck and run a diagnostic test. if any of the solenoids have an issu ( even intermitten ), then the computer will remember it and bring it to the scanners' attention via a "memory code". if the scan yields no codes, then you can pretty much rule out the solenoids.
do as much homework and diagnostic work before "throwing parts at the problem" or tearing into the rig. at this point, it could be a transmission problem, either electgrical or mechanical. it could also be a non-transmission ralated issue, like the drive flange mentioned earlier.
hth
georg @ valley hybrids
ps: i believe rostra makes aftermarket solenoinds for the 440 and 442. if so, then i can get them for a good price for you. if not, then you're limited to good used or brand new oem units.
orangefj45
Supporting Vendor
one more thought;
on some filters/screens there is a gasket or o-ring to help seal the intake area between it and the valve body. if that gasket/oring is missing or damaged, the pump can "suck air" instead of atf, causing the transmission to slip. so while you have the pan off, pull the screen and have a good look.
on some filters/screens there is a gasket or o-ring to help seal the intake area between it and the valve body. if that gasket/oring is missing or damaged, the pump can "suck air" instead of atf, causing the transmission to slip. so while you have the pan off, pull the screen and have a good look.
orangefj45
Supporting Vendor
diagnostic tip
like mentioned earlier, if the trans acts up again, put the shifter down in L and see what happens. that will help narrow things down a bit.
like mentioned earlier, if the trans acts up again, put the shifter down in L and see what happens. that will help narrow things down a bit.
spdwaver
Formerly Kalifornistanian
- Thread starter
- #53
Georg: I will try and answer your questions as I detail the work I performed.
Well, before I caught your reply Georg, I took the solenoids out and tested them according to the FSM. One of them was flawless, the other was not. I cleaned them both out (removed them separately) and the one that was not operating correctly now operated flawlessly.
The method used was to connect a battery to the solenoids to check for the "sound of operation" and to check for lack of low air pressure when electricity is passed through the solenoid. Both performed flawlessly after cleaned (cleaned using mineral spirits, then passed around 70PSI of air through them).
I then proceeded to clean all four solenoids in the same manner.
I checked the gasket around the filter box; this gasket, made of cork, was present and in tact.
As far as the transmission fluid is concerned, it was clean when I bought it; I changed the fluid as PM, which I did not clarify when posting earlier.
I have checked the operation of the transmission by shifting into low. When I do this, it would slowly engage to where it needs to be. The improper operation of the transmission has been (prior to checking the solenoids) very intermittent.
In about 30 minutes I will be putting the fluid back into the transmission and will road-test.
Well, before I caught your reply Georg, I took the solenoids out and tested them according to the FSM. One of them was flawless, the other was not. I cleaned them both out (removed them separately) and the one that was not operating correctly now operated flawlessly.
The method used was to connect a battery to the solenoids to check for the "sound of operation" and to check for lack of low air pressure when electricity is passed through the solenoid. Both performed flawlessly after cleaned (cleaned using mineral spirits, then passed around 70PSI of air through them).
I then proceeded to clean all four solenoids in the same manner.
I checked the gasket around the filter box; this gasket, made of cork, was present and in tact.
As far as the transmission fluid is concerned, it was clean when I bought it; I changed the fluid as PM, which I did not clarify when posting earlier.
I have checked the operation of the transmission by shifting into low. When I do this, it would slowly engage to where it needs to be. The improper operation of the transmission has been (prior to checking the solenoids) very intermittent.
In about 30 minutes I will be putting the fluid back into the transmission and will road-test.
Last edited:
spdwaver
Formerly Kalifornistanian
- Thread starter
- #57
I took it for a five mile test-run just now. Maybe it was not hot enough or maybe it was the cleansing of the solenoids, I really don't know. It ran perfectly. Never before has it shifted as it does now, which is now firm.
Before, when cycling through the gears, the engine would go slightly up in RPM; now, it just shifts very quietly into the next gear; not too firm, not too soft.
I tried everything that I had done before to coerce it into shifting improperly, such as putting it into park, then going back into drive. I also put it into neutral at stop lights as I had done before; not a single problem.
I will report back after I put a few more miles on it tomorrow.
Before, when cycling through the gears, the engine would go slightly up in RPM; now, it just shifts very quietly into the next gear; not too firm, not too soft.
I tried everything that I had done before to coerce it into shifting improperly, such as putting it into park, then going back into drive. I also put it into neutral at stop lights as I had done before; not a single problem.
I will report back after I put a few more miles on it tomorrow.
spdwaver
Formerly Kalifornistanian
- Thread starter
- #58
As mentioned earlier, I changed the fluid; I am not sure how long before I owned it that the fluid was changed.
The seller made no mention of any shifting issues. In fact, when questioned, he was surprised that there was an issue.
After testing the solenoids according to the FSM, they seem perfectly functional; they allow air to pass through when no electricity is present. When electricity is passed through them, air con not pass through.
About a half hour ago, I moved the truck from the driveway to the curb. After I reversed it out of the driveway, I put it into drive; it did the same thing it has been doing: it was trying to move in (seemingly) second or third gear. I then dropped it into "L", and it did not help.
So, now it appears as though this will be taking a ride to a transmission shop to be looked at.
spdwaver
Formerly Kalifornistanian
- Thread starter
- #60
The troubleshooting pages of the transmission section has you count the flashing "OD OFF" light. Problem is, mine does not work. When I turn the OD off, no light. Tried pulling codes, no light.
Is there an alternative to this method, or a way to fix the OD OFF light?
Is there an alternative to this method, or a way to fix the OD OFF light?
