TH425 wont shift into 3rd
June 18th, 2010, 04:44 AM
#1
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Location: Columbus, OH
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TH425 wont shift into 3rd
Like the title says the trans is not shifting into third. Heres the story:
When i got the car i drove it around the block and noticed the car would not shift into second. I found the vacuum line to the trans disconnected. So i hooked it up vacuum port on the intake. Now it shifts into first and second but no third. When i get to around 45mph the car wants to shift into third but it seems like the trans is taking all the air out the engine to shift. Then the car tries to stall. I let off the throttle and played with the shifter and i think it went into third.
I checked the gov and looked at the gears and appeared to be ok. Someone told me to check the cable to the gov and also adjust the shift linkage. I just want to know if any of you guys run into anything like this.
When i got the car i drove it around the block and noticed the car would not shift into second. I found the vacuum line to the trans disconnected. So i hooked it up vacuum port on the intake. Now it shifts into first and second but no third. When i get to around 45mph the car wants to shift into third but it seems like the trans is taking all the air out the engine to shift. Then the car tries to stall. I let off the throttle and played with the shifter and i think it went into third.
I checked the gov and looked at the gears and appeared to be ok. Someone told me to check the cable to the gov and also adjust the shift linkage. I just want to know if any of you guys run into anything like this.
June 18th, 2010, 05:51 AM
#2
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Join Date: Jun 2010
Location: Rogues Island, USA
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Only time this happened to me was when I had a crack in one of those cheap plastic T's that was near the water neck in the vacuum lines. Did the same thing by not shifting out of 1st until about 45mph. This is because the vacuum modulator thinks you're at wide open throttle and that's the normal shift point in that mode give or take a few miles per hour. You're saying it doesn't shift out of 2nd into 3rd?
I would check every vacuum hose under the hood that is tied in to the vacuum modulator in some way. You'll find that vacuum is taken at the intake manifold but may be branched off to several other things under there. You can replace the plastic crap with nice brass T's from a pet store that deals with aquarium supplies.
Other question: Is the vacuum modulator bad? The diaphragm inside could have a leak in it also. They are cheap to replace just to test and see. If you see trans fluid leaking from it you'll know right away. If that doesn't work you'll be going inside the trans and that should be a last resort.
You mentioned the upshift governor, I'll assume you are talking about the small canister on the passenger side that looks like a large breather. Although I've never seen them go bad I suppose a spring or weight in there could have gone bad or maybe the previous owner switched springs and weights out to make it shift at a higher rpm. Those kits are cheap also and easy to check on a Toronado. Just flip the bale wire off and carefully pull the cover off while compressing the weights inside to take a look. Hope this helps
George
I would check every vacuum hose under the hood that is tied in to the vacuum modulator in some way. You'll find that vacuum is taken at the intake manifold but may be branched off to several other things under there. You can replace the plastic crap with nice brass T's from a pet store that deals with aquarium supplies.
Other question: Is the vacuum modulator bad? The diaphragm inside could have a leak in it also. They are cheap to replace just to test and see. If you see trans fluid leaking from it you'll know right away. If that doesn't work you'll be going inside the trans and that should be a last resort.
You mentioned the upshift governor, I'll assume you are talking about the small canister on the passenger side that looks like a large breather. Although I've never seen them go bad I suppose a spring or weight in there could have gone bad or maybe the previous owner switched springs and weights out to make it shift at a higher rpm. Those kits are cheap also and easy to check on a Toronado. Just flip the bale wire off and carefully pull the cover off while compressing the weights inside to take a look. Hope this helps
George
Last edited by TripDeuces; June 18th, 2010 at 09:08 AM.
June 18th, 2010, 08:55 AM
#3
Oldsdruid
Join Date: Dec 2007
Location: Southside Vajenya
Posts: 10,282
Make sure when the shifter shows D the linkage at transmission end is actually in D and not S. You can mess with that at the trans itself. Disconnect the shift rod from the transmission end shift lever, set the lever three clicks down from Park and see what it does. If it works right then, walla!
The steel line to the modulator isn't kinked or pinched, is it?
If the shift linkage adjustment and modulator check out, you need to very carefully adjust the kickdown/converter switch linkage per the shop manual procedure. My guess is something's amiss there and the transmission thinks you want downshift, and it's trying to stay in second.
The steel line to the modulator isn't kinked or pinched, is it?
If the shift linkage adjustment and modulator check out, you need to very carefully adjust the kickdown/converter switch linkage per the shop manual procedure. My guess is something's amiss there and the transmission thinks you want downshift, and it's trying to stay in second.
June 18th, 2010, 01:27 PM
#4
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Join Date: Jun 2010
Location: Columbus, OH
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Thanks guys for the advise. I will check it all out. Too bad i didnt have the time to work on it today since it was busy at work, which is a good thing. Maybe tomorrow i will get the chance to look at the car. Ill post my findings
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