Author Topic: LA-727 upshift to 3rd gear way too early  (Read 1496 times)

Offline Cuda101

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LA-727 upshift to 3rd gear way too early
« on: August 21, 2013 - 09:00:38 PM »
I have a LA-727 transmission and it is up shifting almost immediately from 1-2-3 and very softly.

The trans was rebuilt with a shift kit (unknown manufacturer of shift kit).  It manually shifts fine and firm however with at light (or no) throttle it upshifts to 3rd gear by 15 MPH.

Since this car is not driven much I discovered the problem after the shop went out of business (divorce) so I am stuck.

In the distant past (prior to the rebuild) this happened and I discovered that the governor c clip came off and the governor came loose in the tail shaft and that was the problem and the trans was operating correctly. 

So naturally I thought since I am having the same problem this time it would be the same problem so I pulled the tail housing off (trans is still in the car) however I noticed that the governor clips were intact. 

I disassembled the governor to see if it was sticking and I discovered that the pin (shaft) was worn down (swirl marks on the shaft) so I bought a used governor assembly and installed it and drove the car however the problem continues. 

I just removed the tail shaft again and inspected the governor and the fly weights and they appear to be moving smoothly and the shaft moves smoothly...however after closer look the shaft appears to be a bit too long because the shaft has about a 1/8 inch gap from the governor and the internal c clip that keeps the big fly weight contained.  I would thin that to install the small E clip there should be at least some kind of spring tension.  The governor appears to be assembled correctly.

Is that normal (I cant tell from the online pictures or the service manual???

The governor shaft measures 3.480 inches long.  Is the governor weights supposed to be installed so that there is no spring pressure on the E clip?

Regarding the Throttle valve adjustment:

I pulled the pan and the fluid was OK and not parts in it.

With the transmission pan off I adjusted the throttle linkage so that there is 1/8 inch of gap before the cam moves and pushed the kickdown valve into it's bore when the carb is at idle.  The cam will move fully and it will push the kickdown valve all the way into its bore when the carb linkage is at WOT.

I have the valve body off and disassembled it for farther inspection.

I figure while the pan is off and since I have a 2.9 ratio lever installed now I suppose I should go with a 3.8 or 4.2 so I want to support a shop who is active on this forum (tactransman for example...BTW your PM inbox is full) and hopefully you can provide me some additional support to fix this transmission...PLEASE!>!?!?

Please PM me and I will call you at your convienience




Offline BIGSHCLUNK

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Re: LA-727 upshift to 3rd gear way too early
« Reply #1 on: August 25, 2013 - 12:13:11 PM »
Not trying to be a smartazz here. Is the rod off the carb (or cable if you have the Lokar setup ) adjusted properly. When I got NIKKI she upshifted pretty dam quick. A very minor adjustment cured the problem.  :dunno:
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Offline Cuda101

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Re: LA-727 upshift to 3rd gear way too early
« Reply #2 on: August 25, 2013 - 07:34:08 PM »

Yes...I adjusted the kickdown rod/linkage the usual manner as described in the service manual and that did not fix the problem.  Then I removed the transmission pan and verified that the linkage is moving the internal cam and when the throttle is at wide open the cam pushes the kickdown valve completely into the valve body. So I can verify that the linkage is working correctly.

Since I started this thread I removed the valve body and sent it to Pat Blais in Seattle.  He is the foremost expert on torqueflites.  He is going to disassemble the valve body and inspect it and ensure everything is setup correctly.

I'll let you know.