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3rd to 4th gear flaring??

Frankstein
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Frankstein

Frankstein

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yes it's rpm jumping when it shift ..   mine does it only from 3rd to 4th .     the converter lock on 3rd but when shitfting to OD there's rpm jumping , when in 4th it lock good and eveythings fine!!    ????      Valve body problem??

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notlimah

notlimah

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Is it just the weird jump that rpm's make when going from locked 3rd gear to locked 4th to unlocked 4th? Or something along those lines?! Mine does the same thing between 3rd and 4th and it seems like the trans just can't exactly make up it's mind on what gear it wants to be in.

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Frankstein

Frankstein

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mine does only during the shift from 3rd to 4th.   When I'm on throttle like 40-50%  there's a rpm jump but it seems OK if I try very light throttle when it shift from 3rd to 4th!!     maybe I misassemble the OD section??   governor and TCC solenoid problem??     Notlimah Does yours make the same trouble?         Thanks for reply guys!!!

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notlimah

notlimah

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Yea mine is from 3rd to 4th but it only happens when accelerating under light throttle input. If I'm on it a little more it's hardly noticeable. It basically feels like the trans can't figure out whether it should be in 4th unlocked or locked. It's a slight jerk or surge but it fixes itself quickly. 

 

Heres a a thread I started on what I think you're experiencing/describing. Maybe it'll answer some questions.

 

 

Long story short, it seems normal.

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Me78569

Me78569

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Remember the TC should unlock during the 3/4 shift.  HOWEVER a full flare is not normal.  If you are jumping more than ~200 rpm I would be worried about the health of the trans.  

 

I am going to let dynamic verify tho as I am no expert.

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JAG1

JAG1

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Mine has done it twice under somewhat light accel while hauling the heavy camper and gave it a noticeable clunck sound. I scares my bank book :ahhh:. So I'm wondering what to do also.

 

 

Might be a bad transgender switch for all I know about transmissions.

Edited by JAG1
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dripley

dripley

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1 hour ago, JAG1 said:

Mine has done it twice under somewhat light accel while hauling the heavy camper and gave it a noticeable clunck sound. I scares my bank book :ahhh:. So I'm wondering what to do also.

 

 

Might be a bad transgender switch for all I know about transmissions.

Better get that fixed or we might have to start calling you Jaggett.

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Frankstein

Frankstein

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I guys sorry for late answer .. I was moving location and I got internet today!   I drive my truck all weekend  for moving and it runs great except this 3-4 flaring or slipping  during shift!    Thanks for your input, tomorrow I'll go to my local transmission shop, the guys want to see what it does.   I'll keep you in touch!!

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Frankstein

Frankstein

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Hi, I've been to tranny shop and road test with the guy.  He told me possible cause ...   bad clearance in OD section, solenoid or maybe a valve in the valve body....   He give me a sheet.   for no 4th gear .   it said .   if 9 psi or less in OD port. :solenoid defect. or 3-4 shift valve blocked .....             if around 15 psi. piston seal or ball in piston not there ....      if more than 50 psi.  burn clutch or bad assembly in OD section ... REMEMBER its for no 4th gear ...          SO I put my gauge in OD port to test it!   ...    I have 4th gear..only slippage or flaring during 3-4 shift..     my reading is 100psi at light throttle and more throttle around 115-120-130 psi...   So my conclusion is if I have a bad piston seal, burn clutch or misassambly OD. I would have slippage in 4th gear!!  its not my case, when shifted to 4th it drives fine.  (Remember I have a shift kit)    So my thinking is maybe a valve in valve body not working properly or the 3-4 accumulator??   or OD solenoid??   

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Dynamic

Dynamic

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It's pretty much impossible to have a 3-4 flare unless there's something wrong with the OD roller clutch...

 

During a 3-4 shift, the OD piston on the back of the "main" case pushes against the OD hub. The hub, being forced against the spring pressure of the large OD spring, will slide on the OD sun gear toward the rear of the transmission, immediately releasing the OD direct clutch (which has been carry engaged in all gears up to this point). After forcing the release of the OD direct clutch, and during the time that the OD piston is traveling the distance necessary to engage the OD brake (which will hold the OD sun gear stationary), neither clutch in the OD is engaged, and the torque load transfers to OD roller clutch. Once the OD brake clutch engages at the end of the shift, the sun gear is held stationary, causing the OD planetary set to overdrive the output shaft. At this point, the OD roller clutch simply "free wheels" in there. If the OD roller clutch is not working, the transmission will effectively be in neutral until the OD brake comes on, giving a flare during the shift...

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