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View Full Version : Transmission: '61 Lark shifting issues



GTHawk
06-12-2018, 04:34 PM
My 1961 Lark doesn't want to shift into high when I'm accelerating on the highway. So far it sometimes eventually shifts after I've been driving it awhile. Any suggestions?

RadioRoy
06-12-2018, 04:55 PM
Would you care to say what engine and transmission combination you have?

GTHawk
06-12-2018, 05:16 PM
259 v8 3 speed automatic

thunderations
06-12-2018, 05:35 PM
First thing to check is the fluid level.
Is this problem something new or have you just acquired the vehicle and it has this problem?
There is a sequence of adjustments to make on the accelerator linkage and kick down that affects the speed at which the trans shifts.
Get the instructions for step by step adjustments and try that first, after checking the fluid level.

T.J. lavallee
06-12-2018, 05:59 PM
Be sure to check the transmission warmed up and in drive position to get the actual fluid level not in Park. Be sure to block your front wheels before preforming this procedure! Good luck.

doofus
06-13-2018, 06:17 AM
Seems like my old 63 wagonaire did the same. throttle rod between trans and bell crank on engine needed adj.had to let off gas to get it to shift. adj involved a press guage on trans and a trusted asst. manual is helpful here. Luck Doofus

mbstude
06-13-2018, 07:45 AM
Failing engine/transmission mounts will also change the throttle rod adjustment.

GTHawk
06-13-2018, 10:13 AM
Be sure to check the transmission warmed up and in drive position to get the actual fluid level not in Park. Be sure to block your front wheels before preforming this procedure! Good luck.

Did not know it should be in drive. Will try this and I'll check out the manual and the kick down lever.

Hallabutt
06-13-2018, 03:19 PM
So your trans does no even shift once in drive? If it does shift once in drive, it is operating normally. Unless the valve body has been altered, you have to shift manually into L to access it. Just restating something that I think that you probably already know.

GTHawk
06-13-2018, 07:10 PM
So your trans does no even shift once in drive? If it does shift once in drive, it is operating normally. Unless the valve body has been altered, you have to shift manually into L to access it. Just restating something that I think that you probably already know.

It has occasionally gone into high. Now, with manual shifting, if I start out in low, it will go into second and stay there. If I start out in drive (or second) it stays in second. The fluid seems to be okay. It'll be next week before I can get it on my lift and replace the filter and check the downshift linkage. If I remember right, I think I had this problem before and I changed the filter and it helped for awhile. I'm going to try that again. Will keep you posted.

doofus
06-14-2018, 06:20 AM
GT Hawk if you have to order a press gauge be sure to get a 6 ft hose model.that will just hang inside the vent window to read easily. also dont panic if the throttle rod pops off the bellcrank up front it will snap into place.BTDT yesyerday. had to shorten rod 12 turns to get press right. Luck Doofus

Pckstude
06-14-2018, 09:56 PM
Just a thought. Try Lucas oil for auto transmissions. A Stude friend of mine with a '55 Stude 3spd w/od was having shifting problems. He put in the Lucas gear weight lube, and now it shifts great.

GTHawk
06-22-2018, 07:34 PM
Just want to give an update on my Lark. I got it up on my lift, drained the fluid, cleaned the screen type filter (which was very dirty), checked the kick down linkage (which seemed to be okay), put it back together and it shifts now but sometimes not as soon as it should. We used Type F transmission fluid. Is this correct?

StarDiero75
06-23-2018, 01:32 AM
Could it be the vacuum modulator? My dad's 69 F250 had a modulator issue and it would shift too low, still kinda does. The modulators can be adjusted to allow for different shifts and stuff. I dont know if the almighty Studes have a modulator as my only Stude is my Lark which has 3 OTT+OD

Good luck

StudeRich
06-23-2018, 02:39 AM
Since Stude. Cars have No Vacuum Modulator, control and firmness of shifts is ALL about that Throttle Pressure Control Rod adjustment!

It is not a kickdown Rod or a downshift Rod. :ohmy:

GTHawk
06-23-2018, 03:58 PM
Since Stude. Cars have No Vacuum Modulator, control and firmness of shifts is ALL about that Throttle Pressure Control Rod adjustment!

It is not a kickdown Rod or a downshift Rod. :ohmy:

I learned a new term (Throttle pressure control arm) How do I check pressure?