[Schurkey]

Originally Posted by Schurkey

There is nothing in the shift linkage that will cause a TH400 to start in second gear instead of first gear.

Originally Posted by East

Is this a question or statement?

I ended it with a period, not a question mark. That is a statement.

Originally Posted by East

I have been searching for a reason for a while. I even followed instructions to troubleshoot the governor. It was not stuck or sticking when I removed it; all parts moved freely.

There are some screens for the governor oil, they could be plugged, I guess. Seems to me that'd affect the 2--3 shift, too.

Have you verified the valve body? Governor or valve body is all I can think of PROVIDED REVERSE AND HIGH WORK NORMALLY.

Originally Posted by East

I checked the shifter cable. I even removed the shifter to insure that the cable allowed travel from park to low position on transmission.

If the trans doesn't start in first gear when the selector is in "D", it's not the shift linkage.

Originally Posted by East

If anything, I thought that driving without the kick-down switch connected caused a problem.

Yeah, the problem it causes is that the kickdown doesn't work. Some guys like it that way.

Originally Posted by East

I cannot manually shift into low while driving. It will shift from drive into second speed only.

The shifter will go into the "L" position, but the trans doesn't shift to Low, you only get second.

That's not shift linkage. That's something inside the trans.

Originally Posted by East

If it does start off in 1st/low, it is not detectable to me. I only feel and hear it shift once.

Internal to the trans. Not the linkage. As I said...Governor or valve body (or something really weird.)

[EDIT] Awww, waitaminute. If the one-way clutch for first gear failed, I bet it'd "start" in second. And reverse would still work due to the band. But if that were the case, you should still have manual low.[/EDIT]

[Kenth]

Disconnect the kickdown switch and the TH400 will shift sooner at WOT from standing start.

[Half-Inch Stud]

Originally Posted by Schurkey

There is nothing in the shift linkage that will cause a TH400 to start in second gear instead of first gear.

I think that is true but the 1-2 upshift can be so soon, like 5-8 mph that a fella will only feel 2nd on pullaway.

Wonder what the TH400 code is? surely not PC, PQ, PZ.

Could be a schtuck 1-2 Shift Regultor valve. the 1-2 Shift Valve is waiting for a signal.

How is Reverse? Maybe the 1-2 Accum is clapped out.

[East]

Originally Posted by Schurkey

I ended it with a period, not a question mark. That is a statement.

>>>>>Your statement on punctuation is 100% correct.
Pardon my mistake. No offense intended. <<<<<<<<<<<

There are some screens for the governor oil, they could be plugged, I guess. Seems to me that'd affect the 2--3 shift, too.

>>>>I did not know about screens for governor. I only removed cover and governor. The governor parts moved freely. <<<<<[/B]

Have you verified the valve body? Governor or valve body is all I can think of PROVIDED REVERSE AND HIGH WORK NORMALLY.

>>>>>>>>I have not removed pan or valve body.
I don't drive the car much. Over the past seven years, I have only been driving it to get smog check so that I can register it. The problem has existed prior to that.<<<<

>>>>>>Reverse and drive operate with the exception of manual low and low in drive.<<<<<




If the trans doesn't start in first gear when the selector is in "D", it's not the shift linkage.

That is correct. Cable was removed from shifter to check movement of transmission linkage at each detent (P R D 2 1)

Yeah, the problem it causes is that the kick down doesn't work. Some guys like it that way.

>>>>>I never had a switch for kick down because car originally had TH 350. Would that have caused the problem?<<<<


The shifter will go into the "L" position, but the trans doesn't shift to Low, you only get second.

>>>>>Yes, the shifter is placed in L position from D while driving and does not shift to low<<<<<<

That's not shift linkage. That's something inside the trans.


Internal to the trans. Not the linkage. As I said...Governor or valve body (or something really weird.)

[EDIT] Awww, waitaminute. If the one-way clutch for first gear failed, I bet it'd "start" in second. And reverse would still work due to the band. But if that were the case, you should still have manual low.[/EDIT]

>>>>>>>I have never found the exact answer for my problem when I search online. Thank you very much for your help.

https://www.yellowbullet.com/threads...in-2nd.606958/

https://nastyz28.com/threads/th400-w...2-shift.19415/

https://www.teambuick.com/community/...st-gear.27697/ <<<<<<

[Carousel72TRed]

Just to verify: My GTO when in Drive shifts through all 3 gears starting from a standstill but when I manually shift down to Low from Drive or 2nd it will NOT shift into Low which indicates a linkage or shift lever problem and nothing wrong internally with the transmission.

Carousel72TRed

[78w72]

Originally Posted by Carousel72TRed

Just to verify: My GTO when in Drive shifts through all 3 gears starting from a standstill but when I manually shift down to Low from Drive or 2nd it will NOT shift into Low which indicates a linkage or shift lever problem and nothing wrong internally with the transmission.

Carousel72TRed

what speeds are you doing the downshift to 1st at?

just as an FYI: i used to have a stock th400 in a 78 t/a that didnt downshift to 1st manually while moving unless it was at a certain speed/rpm, you could be doing ~30-35mph & pull the shifter down to 1st & it wouldnt go into first until the car got to a certain speed/rpm, usually about 20mph, then it would drop in. pretty sure this is the case with most stock auto transmissions, they wont downshift unless at a certain speed/rpm. for mine at least, it was not a linkage or shift lever issue, its in the programming of the valve body or governor.

i currently have a TCI th400 with a manual valve body & it will drop into 1st or 2nd regardless of the speed or rpm... to a point im sure, but i can be doing 35-40 mph & pull the shifter to 1st & it will bang into 1st, totally different than the stock th400 i described above.

maybe some others with more knowledge of how the downshifting works can explain this more?

[Carousel72TRed]

78w72,

Thank you for replying. A few (more than a few) I used to be able to get it to downshift manually to low but I had to hold the console shift lever down for it to stay there in low. After the restoration when the motor and transmission were put back in it would not shift down into low manually from 2nd or Drive. From a standstill holding the console shift lever down in low it would shift from 1rst to 2nd like it normally would do in Drive. When I try to shift to low from 2nd or Drive I am going at a very low speed less than 20 mph. My kickdown switch I believe works because when it just shifts into 2nd at a very low speed it will kick down into 1rst. when I get on it. That's why from all the correspondence I have received so far it leads me to believe it is an adjustment problem because my shift cable is stretched or the cable needs to be adjusted properly to the selector lever. Hope I explained it all to you.

Carousel72TRed

[78w72]

Originally Posted by Carousel72TRed

78w72,

Thank you for replying. A few (more than a few) I used to be able to get it to downshift manually to low but I had to hold the console shift lever down for it to stay there in low. After the restoration when the motor and transmission were put back in it would not shift down into low manually from 2nd or Drive. From a standstill holding the console shift lever down in low it would shift from 1rst to 2nd like it normally would do in Drive. When I try to shift to low from 2nd or Drive I am going at a very low speed less than 20 mph. My kickdown switch I believe works because when it just shifts into 2nd at a very low speed it will kick down into 1rst. when I get on it. That's why from all the correspondence I have received so far it leads me to believe it is an adjustment problem because my shift cable is stretched or the cable needs to be adjusted properly to the selector lever. Hope I explained it all to you.

Carousel72TRed

yes that explanation makes sense... i just wanted to mention my experience with stock TH autos & since the speed/rpm wasnt mentioned in the above posts i wasnt sure if maybe that was the issue with yours.

if it downshifted right before the rebuild & nothing else changed then it sounds like it could be a shifter/linkage issue. hope you can figure it out.

[Schurkey]

Originally Posted by Carousel72TRed

I used to be able to get it to downshift manually to low but I had to hold the console shift lever down for it to stay there in low... ... From a standstill holding the console shift lever down in low it would shift from 1rst to 2nd like it normally would do in Drive. When I try to shift to low from 2nd or Drive I am going at a very low speed less than 20 mph. My kickdown switch I believe works because when it just shifts into 2nd at a very low speed it will kick down into 1rst. when I get on it. That's why from all the correspondence I have received so far it leads me to believe it is an adjustment problem because my shift cable is stretched or the cable needs to be adjusted properly to the selector lever. Hope I explained it all to you.

Sounds like a mis-adjusted or defective cable, coupled to the Idiot Proof nature of the stock valve body, which prevents being in first gear if the RPM would be too high. Even with the shifter in "1", the trans will upshift if the speed is high enough. And it won't downshift into "1" if the speed is too high.

Adjust the shifter/cable, see what happens.

Note that your issue is entirely different from that of the original poster.

[track73]

https://www.ebay.com/itm/18446817079...oAAOSw8GFfcs8Z

[Schurkey]

Originally Posted by track73

https://www.ebay.com/itm/18446817079...oAAOSw8GFfcs8Z

Holy crap is that over-priced! Somebody must be "trolling for idiots".

Far as I know, there's two versions of that switch--with the change happening around '69--70. The later switch is by far the most common.

The Treasure Yards are full of 'em.

EVERY ONE needs to be opened-up for cleaning and re-lubing; and then to have the ratchet-slider re-set. The switch is "self-adjusting" but only if the ratchet is moved to the beginning position. Too many folks wind up putting rubber hose over the switch contact arm, where it touches the gas pedal linkage--they don't know how to re-set the switch. Once the initial position is set, adjustment happens when you tromp the gas pedal--you'll hear the switch ratchet to proper position.