overdrive shim help

[nick b]

i am having a delayed shift into overdrive. the solinoid opens but clutches are applying late. so i assumed it was the overdrive shim needed to be thicker. pulled it off and measured it with the measurements i am getting i need a thinner shim. the shim i would need is not even listed in my books not sure what would cause this but does anyone got any ideas

[Big Blue24]

How many clutch/frictions are in the OD/Direct clutch pack... the pack that's engaged with the 820# spring? The more frictions/steels you stack in the OD/Direct pack, the thicker your OD shim needs to be. If you need a thinner than spec OD shim, maybe your clutch pack is really worn or possibly you need to add another steel and friction. The frictions are .063" and steels are .054" or .069" thick. By adding one of each, you'll end up adding .117" which should get you back within the range of OD shims .108-.243"

If I were you, I'd carefully inspect the OD apply piston's seals cause slow OD apply could be a leaking apply piston.

[stubz616]

[QUOTE=Big Blue24;1120897]How many clutch/frictions are in the OD/Direct clutch pack... the pack that's engaged with the 820# spring? The more frictions/steels you stack in the OD/Direct pack, the thicker your OD shim needs to be. If you need a thinner than spec OD shim, maybe your clutch pack is really worn or possibly you need to add another steel and friction. The frictions are .063" and steels are .054" or .069" thick. By adding one of each, you'll end up adding .117" which should get you back within the range of OD shims .108-.243"

If I were you, I'd carefully inspect the OD apply piston's seals cause slow OD apply could be a leaking apply piston.[/QUOTE]

My old tranny used to apply slowly. then it got to the point where i had to get into it hard, let off for it to shift, then get back into it. then finally it quit shifting to o/d all together. when i dissassembled the o/d unit, i found there were little chunks missing off the outer lip seal on the apply piston. When it applies does it apply firmly and late or does it feel like a real weak shift?

[nick b]

okay i will check the direct clutch out i dont think its the piston brand new seal unless i cut it putting it in think i dont have enofugh direct clutches in there if i remember i was not to sure about that part

[nick b]

okay i pulled the clutches out and i have 8 .63 thick ones wich should be correct right?

[Cantankerous1]

Originally Posted by nick b

okay i pulled the clutches out and i have 8 .63 thick ones wich should be correct right?

The direct clutch pack with the big spring has nothing to do with OD, the OD pack is at the front of the OD housing. Thats the one that engages it.

How did you measure the clearance? You have to make sure you have all the endplay out of both pieces to get an accurate measuremnt for shimming.

[nick b]

well from the way i am understanding this issue the direct clutch is to loose witch is causing the clutch hub to sit higher than is needed. which is resulting in me not able to obtain a shim that is called for. i was only aware there was a handful of ways to obtain this measurement the way i prefer is. average the 4 measurements subtract thickness of the straight edge and follow another chart i have not the one in the dodger fsm or the atsg manual. or i can take a 1/2 pice of steel if i have one and use the dodge fsm chart. and i know that the direct clutch would not cause this issue. because it is only used in 1-3 and the overdrive clutches are then used. i have done the math many times it appears i would need a shim about 4 sizes past where the chart stops i use to have a extra direct clutch laying around i was going to pop it in and see if i can get it back into range. but i cannot find it.

[Cantankerous1]

The OD direct clutch pack is spring apply and all the clearances are internal to it. They don't effect the OD clutch pack, thta is clearanced off the rear housing support and the OD unit. If your off the chart either you aren't getting the endplay out or your OD clutch pack is shot.

[nick b]

not sure what method you are using to measure clutch packs is but i would sure like to know? i never touch to od clutches on determining the shim thickness just measure it off the direct clutch hub. and yes i know it it is applied by springs but the more clutches you add the lower the hub will sit where the selective shim sits. because the clutches determine spring tension and hub height.
in my case i have determined that the direct clutch is disengaged before the piston applyes the od clutches because i had a .183 shim so i need to add another clutch and steel to the direct clutch pack witch was stated above. and these are new clutches

[Big Blue24]

Originally Posted by Cantankerous1

The OD direct clutch pack is spring apply and all the clearances are internal to it. They don't effect the OD clutch pack, thta is clearanced off the rear housing support and the OD unit. If your off the chart either you aren't getting the endplay out or your OD clutch pack is shot.

You obviously don't have a clue.


** Don't listen to this keyboard racer **

[Big Blue24]

Originally Posted by nick b

okay i pulled the clutches out and i have 8 .63 thick ones wich should be correct right?

You should have 9 clutches in the OD/Direct pack. If you buy the thinner steels, you can actually fit 10 frictions and still stay within the range of factory shims.

Go to wittrans.com and order a couple extra frictions and get all 4 of the OD shim sizes, probably just get the cheaper used ones, they have a "U" at the beginning of the part number.

Getting the OD/Direct pack back to spec will get your OD shim clearance back to spec, but I still suspect you might have a bad seal on the OD piston.


How do you have the OD frictions, steels, and reaction and pressure plate stacked? It's possible that your OD pack is flexing into a cone shape. It's the easiest pack to pull apart, check the frictions for wear and steels for flatness.

[nick b]

Originally Posted by Big Blue24

You obviously don't have a clue.


** Don't listen to this keyboard racer **

just pulled the piston out there was a rofugh spot on it but no cuts nor was it rolled so i think we can rule that out i will prolly replace it just cause im there although there is less than 200 miles on it.i am missing a clutch i use to have it but it seemed to dissapear the direct clutch steels show signs of slipping. as for the od clutches everything looks good all steels are flat no wear marks on them
thanks for the help on this big blue your the only one in the thread that seems to know what is going on

[Cantankerous1]

Originally Posted by Big Blue24

You obviously don't have a clue.


** Don't listen to this keyboard racer **

Your an IDIOT thats whats obvious. But hey, even idiots get to have a say in things. Just gotta weed out the BS.


Good luck on figuring out the problem, I would detail the process for you but looks like you made up your mind.

[Big Blue24]

Originally Posted by Cantankerous1

Your an IDIOT thats whats obvious. But hey, even idiots get to have a say in things. Just gotta weed out the BS.


Good luck on figuring out the problem, I would detail the process for you but looks like you made up your mind.

If you think direct clutch pack thickness in the OD section has nothing to do with selecting the proper shim for the overdrive piston, you are the one posting BS that needs to be weeded out.

[Big Blue24]

Originally Posted by nick b

just pulled the piston out there was a rofugh spot on it but no cuts nor was it rolled so i think we can rule that out i will prolly replace it just cause im there although there is less than 200 miles on it.i am missing a clutch i use to have it but it seemed to dissapear the direct clutch steels show signs of slipping. as for the od clutches everything looks good all steels are flat no wear marks on them
thanks for the help on this big blue your the only one in the thread that seems to know what is going on

Sounds like all you need to do is add another clutch to the OD/Direct clutch pack and get the proper shim.

In my mind, if the OD clutches are not showing signs of wear but the direct clutches are, sounds like the OD clutch is being applied correctly and the OD/Direct clutches are not fully disengaging/dragging. That would cause the sensation of slow OD application because there would be a half second of bind-up on the 3-4 shift.

Obviously if you get the OD/Direct pack shimmed correctly, the direct pack will fully release before OD engages and you'll be left with a crisp firm 3-4 shift.

[Cantankerous1]

Originally Posted by Big Blue24

If you think direct clutch pack thickness in the OD section has nothing to do with selecting the proper shim for the overdrive piston, you are the one posting BS that needs to be weeded out.

You clown, your puking BS every time you touch the keyboard! Get out of your parents basement and do something with a transmission and you might be able to understand. Evidently reading is not your strong suite as the FSM DETAILS the assembly.

The OD direct section is aseembled first UNDER 800 PSI pressure in a contained unit that is dropped into the OD housing a unit. There is NO, NONE, NADA shims in the OD directs, its a spring apply and doesn't care what the clearance is.

The OD clutch pack is shimmed off the direct hub after it is installed in OD housing and all the way to the rear of the housing OR THE DRIVE TRAIN CLEARNCES AR OFF. The OD apply piston spacer is selected off the measurements from the intermediate support housing and the rear of the case.

Again, the OD directs have ZERO bearing on the OD clutch pack and their operation. All shimming and spacing is done AFTER the the direct clutch pack is assembled and installed in the housing.

Good job!!! You just convinced the OP to tear apart 3 times as many pieces as he had to when the problem is a bad seal and piston in the OD clutches. IF THE CLEARNACES WERE TOO FAR OFF OD WOULD NEVER ENGAGE!!!! If you had even an iota of experience with these units you would have known that, keyboard racer!!! Now clean up the mess you made and the misinformation you fed the poor guy with a problem.


Here's Your Sign !!

[nick b]

hmm if he is wrong then why did it fix it he must obviously know something because nothing you said seemed to help or even make sense you seemed more interested in arguing the whole problem and insting you were right. his soultion made sense to me the second i read it

[Big Blue24]

Originally Posted by Cantankerous1

You clown, your puking BS every time you touch the keyboard! Get out of your parents basement and do something with a transmission and you might be able to understand. Evidently reading is not your strong suite as the FSM DETAILS the assembly.

The OD direct section is aseembled first UNDER 800 PSI pressure in a contained unit that is dropped into the OD housing a unit. There is NO, NONE, NADA shims in the OD directs, its a spring apply and doesn't care what the clearance is.

The OD clutch pack is shimmed off the direct hub after it is installed in OD housing and all the way to the rear of the housing OR THE DRIVE TRAIN CLEARNCES AR OFF. The OD apply piston spacer is selected off the measurements from the intermediate support housing and the rear of the case.

Again, the OD directs have ZERO bearing on the OD clutch pack and their operation. All shimming and spacing is done AFTER the the direct clutch pack is assembled and installed in the housing.

Good job!!! You just convinced the OP to tear apart 3 times as many pieces as he had to when the problem is a bad seal and piston in the OD clutches. IF THE CLEARNACES WERE TOO FAR OFF OD WOULD NEVER ENGAGE!!!! If you had even an iota of experience with these units you would have known that, keyboard racer!!! Now clean up the mess you made and the misinformation you fed the poor guy with a problem.


Here's Your Sign !!

Cantankerous if I lose you, go back to CumminsForum, they openly embrace the blind leading the blind.

It is true that the direct drum assembly slips down into the OD housing, and it is held in place with a snap ring on the output shaft bearing. What you're failing to realize is that the thickness of the direct/OD clutch pack affects the clearance or overall height of the direct drum. In fact, the direct drum slides up and down on the OD sun gear.

When OD applies, the piston moves into the OD section, pushes the direct drum downward which disengages the direct/OD clutches and at nearly the same time engages/compresses the OD clutches aka brake clutches that stop the OD/Ring Gear from turning. When the ring gear stops turning, it forces all power to run through the OD planetary gear which gives you 0.69 OD ratio.

When selecting an OD shim, the average of 4 measurements are taken from the face of the OD case to the face of the OD/Direct drum. Since this drum is a sliding drum that is held in place with a spring, the clutch pack thickness determines how far the drum slides up the sun gear. As the clutch pack wears, the drum slides further and further up the sungear making the clearance between face of hub and face of OD case less.

If the pack was missing 1 clutch and 1 steel, the face of the drum would be too close to the face of the OD case and therefore it would be out of the range of shims for the OD piston. Selecting the proper OD shim is important because too thin of a shim will cause the OD brake clutches to engage before the direct clutches are released, creating bind up and accelerated wear on the OD brake clutches. Too thick of a shim disengages the direct clutches too quickly and would cause a flare between shifts except for the fact that there is an over-running one-way roller clutch that would prevent engine flare between shifts. This clutch would experience accelerated wear if too thick of an OD shim were selected and would prematurely fail.

[zstroken]

Originally Posted by Big Blue24

Cantankerous if I lose you, go back to CumminsForum, they openly embrace the blind leading the blind.

It is true that the direct drum assembly slips down into the OD housing, and it is held in place with a snap ring on the output shaft bearing. What you're failing to realize is that the thickness of the direct/OD clutch pack affects the clearance or overall height of the direct drum. In fact, the direct drum slides up and down on the OD sun gear.

When OD applies, the piston moves into the OD section, pushes the direct drum downward which disengages the direct/OD clutches and at nearly the same time engages/compresses the OD clutches aka brake clutches that stop the OD/Ring Gear from turning. When the ring gear stops turning, it forces all power to run through the OD planetary gear which gives you 0.69 OD ratio.

When selecting an OD shim, the average of 4 measurements are taken from the face of the OD case to the face of the OD/Direct drum. Since this drum is a sliding drum that is held in place with a spring, the clutch pack thickness determines how far the drum slides up the sun gear. As the clutch pack wears, the drum slides further and further up the sungear making the clearance between face of hub and face of OD case less.

If the pack was missing 1 clutch and 1 steel, the face of the drum would be too close to the face of the OD case and therefore it would be out of the range of shims for the OD piston. Selecting the proper OD shim is important because too thin of a shim will cause the OD brake clutches to engage before the direct clutches are released, creating bind up and accelerated wear on the OD brake clutches. Too thick of a shim disengages the direct clutches too quickly and would cause a flare between shifts except for the fact that there is an over-running one-way roller clutch that would prevent engine flare between shifts. This clutch would experience accelerated wear if too thick of an OD shim were selected and would prematurely fail.

I would agree except I can't see the too thick of an OD shim causing the overrunning clutch to wear out and fail.

[nick b]

if the direct clutches were to loose it would slip more causing the sprag to do more work than nessacary it would be engaged all the time almost and wear out. does that sound right i had to replace mine