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The original transmission is removed from 1966 Olds Toronado. I would like "good" clutches and a shift kit installed. Will the shift kit for a TH400 work ? I don't believe the Toronado had a "switch pitch", am I correct ?
Last edited by OLDSter Ralph; December 19th, 2018 at 09:25 AM.
I believe the 66 was a Switch Pitch but not sure about the other years. I'm sure getting parts for a TH425, which is what you have, is simple to come by. Valve bodies between a TH400 and a TH425 are not the same. TransGo makes a shift kit specifically for the TH425.
There is a 2 prong electrical fitting on the drivers side of the case. Energize the top terminal with 12v and listen for the solenoid click. If you hear it it's a switch pitch.
Last edited by TripDeuces; December 3rd, 2018 at 08:23 AM.
Thanks. The trans is out of the car waiting to be torn down. It leaked like a sieve and slipped on the 1 to 2 shift. If its a "switch pitch" I want the best parts available installed. This is my first Toronado, so I don't know much about them.
Well, the trans was gone through and a Trans Go 425-1 Reprogramming Kit installed. Everything worked fine til I got half way home and stopped at another stoplight. The trans wouldn't shift up. I tried shifting manually up and down. Nothing happened, it stayed in low gear. I checked vacuum lines to see if one was cracked and was leaking or got loose (disconnected). Any ideas what went wrong ? I am wondering if the kick down switch went bad.
Will it shift out of first eventually around 40-45mph? Like it was at full throttle?
I believe that was one of the things I tried and it didn't upshift. I had to drive about 15 miles and I did have traffic backed up at times. I will warm it up later today and verify that.
If it does shift to 2nd eventually around 45mph then more than likely it's just a leak in the vacuum line to the modulator. Many of the 't's, elbows, etc.' are made of plastic. Sometimes they crack but don't break off leaving a hairline crack and a leak. Happened in my 70 Toronado. Factory 'T' broke, replaced it with a brass 1/8 T.
If the modulator senses a low vacuum signal it assumes you are in a WOT mode and holds the transmission in gear for max acceleration, only shifting at the governor settings. It's a simple test to just stomp on it and see if it shifts.
Last edited by TripDeuces; December 19th, 2018 at 08:38 AM.
Most likely a vacuum issue, or the govenor valve is stuck. I’d pull the govenor our for and inspection, assuming the vacuum suppply to the modulator us good.
If the modulator has a metal line connected with a short rubber nipple on both ends verify the metal line isn't obstructed. Verify the passing gear switch and wiring is working and has voltage.
Had this happen on my 68 TH400. WOT up-shifts only. The 1-2 upshift made 20 foot 11s on the road! Awesome! But hard to drive that way. Like a dumb kid I grabbed the line and ripped it out and replaced with all rubber. Its one of the remaining items left to replace on this car. Ill bet inline makes it.
This was/is a nasty shifting trans to start with. Some day Ill rebuild it and reinstall it as it it the # case for the car. Manual shift TCI 400 in there now, stout but nothing like the brutal dual fed animal.. Maybe when I rebuild it Ill have ta tone it down a bit by removing the dual feed and lowering the line pressure to normal ranges....NOT!
Today I started it to warm up and drive to the auto parts store. It shifted as if nothing had happened. I was going to check vacuum at the modulator when I got back. Now I am thinking something stuck before and snapped back while sitting.
Update: I still have a problem.
1. When cold (freshly started) it shifts as tame as a ***** cat with very nice, quick shifts.
2. When it warms up after a few miles, it will not shift into 3rd.
3. When its driven more, I have only 1st gear.
Moving the car gear shifter, can slam hard when it shifts 1-2. I have tried to manually shift it and it only goes as high as 2nd gear. When its warmed more, it won't shift out of L..
I have tried numerous stop and pull gear shifter in L and manually shifted up and it never made 2-3 shift. And when warmed up more, it stays in 1st.
It almost like no gear is engaged after revving in 2nd (S). It does not shift (governor) when revved.
The transmission was overhauled because it was leaking badly, but it shifted just fine. It has the Trans Go 425-1 Reprogramming kit installed. It has extra clutch plates installed.
Last edited by OLDSter Ralph; August 22nd, 2021 at 12:45 PM.
Reason: more info
Did you replace the modulator? If so, did the problem start with the modulator replacement? Disconnect the modulator vacuum line with the engine running, there should be a noticeable difference in the way the engine idles. If not, make sure the vacuum line isn’t kinked or restricted.
What’s the condition of the vacuum modulator line itself? It should be metal, with just a little hose on either end for vibration. Don’t use any more rubber hose than absolutely needed, rubber can collapse and cut off or reduce the vacuum modulator, causing harder/later shifts. Sound familiar?
Disconnect the kickdown electrical connector, see if that makes a difference. I wouldn’t expect a switch to malfunction on a predictable basis based on temperature, but screwy things happen.
Connect a line pressure gauge to the line pressure port. On a 400 trans, it’s above the linkage for the shifter. I would assume it’s in the same place.
Tee in a vacuum gauge to the vacuum modulator. Tape both gauges to the windshield where you can see them while driving.
See what the line pressure is when the engine is cold, same as the vacuum. Since line pressure is regulated by the pressure regulator valve, the transmission temperature should have a minimal influence on what the pressure is.
As you drive the car, the vacuum gauge should move instantly depending on throttle and engine load. As the vacuum drops, line pressure should also immediately but smoothly increase.
As the engine warms up, if the line pressure increases and then stays elevated, if inspect the modulator valve itself to see if it sticks in the case. Remove the modulator, the valve is inside the case. You should be able to pull it out with needle nose pliers or a magnet. Polish the valve with some scotch bright, clean the bore with brake clean, reinstall and reinstall. Drive it and see what happens.
Hopefully it’s fixed. If not, then hopefully you can see a change in either vacuum or line pressure that is related to the malfunction.
Success at last. A shift valve that came in the Trans Go 425 shift kit was replaced with the original. They couldn't see anything suspect with the Trans Go valve. But when the original was put back in, everything worked perfectly.
The transmission shop has used Trans Go shift kits in TH350 and TH400's and never had a problem. I am suspecting something about the shift valve in this kit was defective. I think it might be only the one included in my kit.
I drove it 50 miles yesterday in various conditions and it shifted flawlessly. I can't tell you how happy I was cruising down the highway at 70-75 MPH floating on a cloud.
Good deal. Sounds like the shift valve TransGo included was just a tiny bit oversized, once the valve/valve body warmed up the valve jammed. That’s my theory. As long as it works that’s all that matters
I originally picked up the Toronado in mid December and it was cold enough in Minnesota to allow me to get farther away than the test drive. During this summer, it was warm enough to malfunction in about 3-4 miles.
It was a learning experience for the tranny shop owner and myself. He is also a drag racer and builds his own TH400's.
He was all smiles when I showed up to get it on Friday. Thank you for your thoughts and wisdom.
I loved the TransGo kit in my 70 TH425. I think TransGo is pretty decent overall for whatever your build. Doing a TransGo TH400 kit now.
The modifications and rest of the stuff from the shift kit are still in the transmission. There was something about that particular valve from the shift kit and my valve body that caused the problem. I think the shift kit is good, it was just something in the valve from the kit and my valve body causing it to stick when it got warm.
Don't get me wrong, I love the firm, crisp shifts. Now I have all the gears all the time. Before, I had only low, sometimes 2nd when it warmed up.
One of my first jobs was delivering pizzas. We had two Toro's. I was addicted immediately. I owned a one owner 69. I can't even imagine how much I would have loved a shift kit in that car. I Will have another Toronado someday. Colorado life? Best freaking snow car ever.
December 2nd, 2018, 06:28 PM
