Hi Guys & Gals.  My old Targa Blue Coupe with a 350 CI 200 HP Turbo Hydro 400 has had a shifting problem for the past several years.  Very occasionally it will not shift from 2nd to 3rd.  Eventually it always shifts into 3rd and only does it about once a year so I never worried too much about it.

It did it again this spring (would not shift), so before my trip to Bloomington Gold in St. Charles IL., I took it to my mechanic and we did a vacuum test on the shift modulator and it tested good, however, the two hoses had some small cracks so we replaced them.  We also put a can of Sea Foam in the transmission for good luck.  I drove it for several days before Bloomington Gold and it shifted great.  Problem solved.  NOT!

 Friday morning I left for St. Charles and it worked great until a got to Rockford IL and stopped for gas.  Got back on the Interstate and it would not shift into 3rd.  This time it would not eventually shift into 3rd.  The best i could do was about 45 MPH at 3000 RPM.  Cars and trucks flying past me doing 75.  Not good.  Pulled off and let it sit and cool down for about an hour.  Engine water temp was normal, about 200-210.  Air temp was now about 80.
After sitting about an hour, tried it again and now shifted fine.  Drove the rest of the way to St. Charles and it worked great.

Met Dick and Jill Countryman for lunch and enjoyed Bloomington Gold.  Left St Charles about 4PM and it shifted very sporadically.  Some times it would shift and some times not.  By now the air temp is in the 90s,  but engine temp is still normal.  I got about 30 miles from the home farm near Pontiac, IL and it would not shift at all.  Drove the last leg of the trip in 2nd gear.  45MPH @ 3000 RPM.

The next morning, it worked fine, shifted every time.  Until it got hot.  Then it started missing shifts.
So that's where I am now.  Shifts great when cool,  will not shift from 2nd to 3rd when hot.
I know there is a governor in there but I'm not sure what that does.

Any thoughts and ideas would be appreciated.  Thanks in advance for your help.

Dean

 

 





|UPDATED|6/25/2012 1:24:23 PM (AZT)|/UPDATED|

Get pan dropped and change filter and fluid , also have then pull governor and clean it as well as check kick down solenoid to make sure it is not sticking and holding you from up shifting , There are also little screen filters on that tranny that plug up have mechanic pull them out .   

Dean, even if the problem was with the modulator, the trans would still shift if you wound it up. Since you've already checked the modulator, and repaired the lines, that's prolly not the problem. A bad mod would effect both the 1-2 AND the 2-3 shift, anyway.
It's possible the problem is with the governor. It is located on the right rear of the trans, and has a square cover with 4 bolts holding it on. Take the cover off, twist the governor out, and check the nylon gear on the end of the gov. Check to see that the gear is nice and tight in the metal part of the gov...it should NOT be loose. Also look to see if the gear is "apple cored" in the center, meaning, it is worn in the center, but not at the ends. If you see wear in the center, then that might be the problem. The gear is replaceable, if damaged. Just knock the tiny roll pin out, and pull the gear out. To install the new gear, you will need to fully seat the new gear into the governor body, and drill a hole thru the plastic gear to install the roll pin.
The kickdown solenoid on the valve body could possibly be clogged up, causing a no shift, but that would normally also effect the 1-2 shift.
It's also possible that there is a valve sticking in the valve body when it gets hot, but that's more of a long-shot than anything. The description really sounds more like a governor issue. I would suggest removing the governor first, and checking it out. If no problems are found with it, then it's time to dig a little deeper into the trans, by pulling the pan, and seeing what kind of poop might be in there causing problems.

A total long-shot idea would be if the kick-down switch(or wiring) above the accelerator pedal is damaged. You might try disconnecting the wire on the left side of the trans as a test for that.


|UPDATED|6/27/2012 2:48:49 PM (AZT)|/UPDATED|

Tony and Joel, thank you for the replies and suggestions.  I dropped the pan and changed the fluid and filter
about 6 or 7 years ago but it only has about 4000 miles on it since then.  Some years I don't put 1000 miles on it.
The car is still in Pontiac IL at my brothers, so I'll have him and a good friend, who is also an excellent mechanic, check the governor.


Thanks again guys and I'll let you know what we find out.

Dean
 

|UPDATED|6/25/2012 8:40:02 PM (AZT)|/UPDATED|

Thank you, Joel.

  "IF" this is OFF TOPIC, I apologize. I see many problems resolved for co-members and their cars addressed on this site. With the knowledge and abilities of minds that are MORE than willing to assist us, I find GREAT satisfaction in this group of people. THANKS to the ones who make this possible. If you are a new person to the site, STICK AROUND, attend some functions of the C3VR, and enjoy the friendship, fun, and willingness to help each other.

I have a guy that I have a lot of confidence in that will remove the governor and check it, but he is hesitant to go to the work of removing it without having a new on on the shelf to put back in.  Therein is the problem.  Can't find one anywhere.
I have tried local parts houses, after market parts suppliers, and Summit Racing.  Not to be found.  The part is obsolete.
He also has a gut feeling that may not solve the shifting problem.  Couple of questions.
Do any of you (Joel) have a source for one or have one laying around?
If the governor does not work, then I'm looking at a transmission re build.

If that's the case, then I think I'd be much better off with a 4 speed trans.  I know many of you have replaced your 3 speed with a 4.  What are your experiences?  What do you have to alter?  Which one do you recommend?  Do you use the same shift stick?
I would appreciate any input.
Thanks in advance.

Dean

Dean, the governor itself does NOT need to be replaced. At the most you will need to replace the gear. Gears are available at any trans shop...prolly $3 or so. They would prolly change the gear for you for a few bucks more.
I know it ain't fun going thru a lot of hassle to remove something just to check it, but...it's cheaper than a rebuild.
If you cannot find a trans shop in your area, I can send you a gear. I have a BOX full(50+!) of 700R4 gov gears at home, but the 400 gear has teeth that are angled backwards from the 350/700 gear. I can get the 400 gears, tho, no problem.
The governor is specific to the car, so you really don't wanna just swap a different one in there, unless the weights and springs are exactly the same as your original. I'd say it is worth the effort to at least check the governor before anything else....just my opinion.

Ya know whut? I just remembered..I have a couple of 400 cores at the house too...at least ONE of them should still have a governor in it. It would not have the correct weights/springs for a Corvette, tho....

Just wanted to give an update on my shifting problem on Ole TargaBlue.
My brother and I loaded her up on a trailer and hauled her from Pontiac IL to WI.  Easy trip.
I'm sure that if I were to drive it, after 2-3 hours on the Interstate, at 65 to 70 MPH it would heat up enough that if
I stopped, it would not make the 2-3 shift.  I've had enough experience with that.
Right now it shifts great, never misses until it gets hot.

I have talked to a number of trans. shops and guys, and nobody is convinced that changing the governor or gear in the
governor will solve the problem.  Sooo, I'm looking at a trans rebuild. 

I've also looked at and talked to people about a trans. swap to a 700R 4.  That is very expensive and not an easy swap.
Many modifications.  I know many of you have done it, but I just don't put enough miles on that thing to justify it.
If anyone has additional thoughts or information, I would welcome them.
Thank you to all that replied and offered suggestions.

Dean
 


|UPDATED|7/4/2012 10:21:55 AM (AZT)|/UPDATED|