TH350 late shift into 3rd and shaky reverse
#1
TH350 late shift into 3rd and shaky reverse
Hey guys. So.... I already have consigned myself to the bad news, but it's not actually THAT bad because my brother in law has a good friend who rebuilds transmissions for a shop and is prepared to give both of us a class on how it works and how to rebuild it. We've recently overhauled the engine, so it's not that much of a surprise the tranny is on it's way out.
But just in case there's something I haven't read about already, here are the symptoms:
When it's cold, I have no reverse. I have to wait for the engine to warm up before I can get full reverse to pull out of my carport. Even then, reverse seems a little shaky and I cannot apply too much throttle when in reverse or else I can feel the bottom end shake quite a bit.
The next symptom that only recently started happening is the late shifting into 3rd gear. 1-2 is nice and noticeable around 15-20 mph, but 2-3 doesn't want to happen until about 45mph, if at all. And when it does shift into 3rd, it stays there just fine until I decrease speed. However, from a stop, those things happen all over again.
I've read that reverse and 3rd gear share the same clutch pack, and even though I have no clue what that is, I did read that it generally means a rebuild. But I have also read that maybe it's the governor. I don't know, I'm not sure.
Things I have done recently to help with the no reverse when cold problem include: install new transmission fluid filter, new fluid and Lucas transmission fix. - Didn't seem to fix.
Also, when the problem started with not wanting to shift into 3rd, I bought and intalled a new modulator. There are no vacuum leaks and all the way down from the manifold to the modulator i'm getting a good 19in of vacuum. I also tried to field adjust the modulator for the late shifting, and got a nice hard 1-2 shift, but nothing affecting 3rd.
If it could possibly be anything else, I'm willing to give it a shot before yanking the thing and getting help rebuilding it, even as much as I dearly want to learn about it; I'd rather be driving it.
Any info or advice is appreciated.
I don't want to be without my 72 Vista for too long! So thanks!
But just in case there's something I haven't read about already, here are the symptoms:
When it's cold, I have no reverse. I have to wait for the engine to warm up before I can get full reverse to pull out of my carport. Even then, reverse seems a little shaky and I cannot apply too much throttle when in reverse or else I can feel the bottom end shake quite a bit.
The next symptom that only recently started happening is the late shifting into 3rd gear. 1-2 is nice and noticeable around 15-20 mph, but 2-3 doesn't want to happen until about 45mph, if at all. And when it does shift into 3rd, it stays there just fine until I decrease speed. However, from a stop, those things happen all over again.
I've read that reverse and 3rd gear share the same clutch pack, and even though I have no clue what that is, I did read that it generally means a rebuild. But I have also read that maybe it's the governor. I don't know, I'm not sure.
Things I have done recently to help with the no reverse when cold problem include: install new transmission fluid filter, new fluid and Lucas transmission fix. - Didn't seem to fix.
Also, when the problem started with not wanting to shift into 3rd, I bought and intalled a new modulator. There are no vacuum leaks and all the way down from the manifold to the modulator i'm getting a good 19in of vacuum. I also tried to field adjust the modulator for the late shifting, and got a nice hard 1-2 shift, but nothing affecting 3rd.
If it could possibly be anything else, I'm willing to give it a shot before yanking the thing and getting help rebuilding it, even as much as I dearly want to learn about it; I'd rather be driving it.
Any info or advice is appreciated.
I don't want to be without my 72 Vista for too long! So thanks!
#4
Just an Olds Guy
Join Date: Jul 2008
Location: Edmonton, AB. And "I am Can 'eh' jun - eh"
Posts: 24,525
When it's cold, I have no reverse. I have to wait for the engine to warm up before I can get full reverse to pull out of my carport. Even then, reverse seems a little shaky and I cannot apply too much throttle when in reverse or else I can feel the bottom end shake quite a bit.
The next symptom that only recently started happening is the late shifting into 3rd gear. 1-2 is nice and noticeable around 15-20 mph, but 2-3 doesn't want to happen until about 45mph, if at all. And when it does shift into 3rd, it stays there just fine until I decrease speed. However, from a stop, those things happen all over again.
Also, when the problem started with not wanting to shift into 3rd, I bought and intalled a new modulator. There are no vacuum leaks and all the way down from the manifold to the modulator i'm getting a good 19in of vacuum. I also tried to field adjust the modulator for the late shifting, and got a nice hard 1-2 shift, but nothing affecting 3rd.
The next symptom that only recently started happening is the late shifting into 3rd gear. 1-2 is nice and noticeable around 15-20 mph, but 2-3 doesn't want to happen until about 45mph, if at all. And when it does shift into 3rd, it stays there just fine until I decrease speed. However, from a stop, those things happen all over again.
Also, when the problem started with not wanting to shift into 3rd, I bought and intalled a new modulator. There are no vacuum leaks and all the way down from the manifold to the modulator i'm getting a good 19in of vacuum. I also tried to field adjust the modulator for the late shifting, and got a nice hard 1-2 shift, but nothing affecting 3rd.
No reverse till warm likely a blockage somewhere in the valve body for reverse gear. Warming the fluid may be what's allowing partial flow and stutter in reverse.
When you pulled the pan and changed fluid did you check for filings in the bottom of the pan? It's normal for a blackish gunk (that's clutch material), but if you had filings that's an indication of a more serious problem. It doesn't take much contamination to cause transmission problem.
#5
I did notice the blackish gunk, but no filings. I was told to look for that and found none.
I do believe we will rebuild the thing in the next couple of weeks. I was just hoping that maybe there was something I could have missed reading about.
Thanks for the responses! I'll most likely post about my rebuild experience in case it can help anyone else out.
I do believe we will rebuild the thing in the next couple of weeks. I was just hoping that maybe there was something I could have missed reading about.
Thanks for the responses! I'll most likely post about my rebuild experience in case it can help anyone else out.
#6
Just an Olds Guy
Join Date: Jul 2008
Location: Edmonton, AB. And "I am Can 'eh' jun - eh"
Posts: 24,525
If you use this car a lot for highway? Go find a used 200 4R or 700 4R and use it instead. It will give you much better highway mileage. Final drive ratio on a TH350 is 1:1. Final drive ratio on a 200 or 700 4R is .67:1. Cost of rebuild is about the same. Just need to relocate the trans cross brace and install a throttle valve (TV) cable to your setup. You won't have to change the driveshaft, but may have to change or shorten the e brake cable.
On the other hand, if you already have tall gears in the VC, carry on with the TH350. It's a good strong trans that should give you many more miles of trouble free motoring.
On the other hand, if you already have tall gears in the VC, carry on with the TH350. It's a good strong trans that should give you many more miles of trouble free motoring.
#7
It's a cruising around town and gulf coast on the weekends car. Not too too much highway traveling except the occasional 30 mile ride to New Orleans and maybe to Pensacola, Fl once a year. I did think about going with a 4 speed, but I might tackle that a couple years down the line.
I definitely appreciate the input!
I definitely appreciate the input!
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