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60 Valiant - general question about transmission
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Author:  Eatkinson [ Mon Jan 03, 2005 4:54 pm ]
Post subject:  60 Valiant - general question about transmission
I have a '60 V. most everything seems normal w/the transmission. It shifts fine, etc. My question is about the driving "feel" of it. I have a 64 dart w/a 225 +torqueflight auto and it runs very smoothly compared to the Valiant. I know the A904 auto trans in the '60 Valiant is a smaller version of the torqueflight, but it doesn't sound nearly as smooth.

My question is, in these cars, is the engine supposed to be torqued up at high revolutions even at speeds like 35-50? I know the trans is in 3rd gear when i drive it - I can clearly hear it shift through all three at what seem to be appropriate intervals. But the engine seems torqued high compared to the Torqueflight in my '64 dart which is absolutely smooth.

The car sat for 34+ years, and i've recently got it going again. The fluid is not old, it's clear, no bubbles, checked by a mechanic familiar with these cars.

Thoughts?
Author:  Chrycoman [ Tue Jan 04, 2005 12:06 am ]
Post subject:  Re: 60 Valiant - general question about transmission
Quote:
I have a '60 V. most everything seems normal w/the transmission. It shifts fine, etc. My question is about the driving "feel" of it. I have a 64 dart w/a 225 +torqueflight auto and it runs very smoothly compared to the Valiant. I know the A904 auto trans in the '60 Valiant is a smaller version of the torqueflight, but it doesn't sound nearly as smooth.

My question is, in these cars, is the engine supposed to be torqued up at high revolutions even at speeds like 35-50? I know the trans is in 3rd gear when i drive it - I can clearly hear it shift through all three at what seem to be appropriate intervals. But the engine seems torqued high compared to the Torqueflight in my '64 dart which is absolutely smooth.

The car sat for 34+ years, and i've recently got it going again. The fluid is not old, it's clear, no bubbles, checked by a mechanic familiar with these cars.

Thoughts?

The transmission in your 1960 Valiant is the A904 Torqueflite. The transmission in your 1964 Dart is the A904 Torqueflite.

Although the engine in your Dart is a 225 slant six with 145 bhp, the 1960 has a 170 with 101 bhp. So the smaller engine will definitely be working harder than the 225. Also, there may be differences in sound deadening materials.

Just how old is the transmission fluid? It does not sound like you changed it recently. Personally I would change the fluid in the transmission and torque converter. Although it may look good, it may have deteriorated which would affect the efficiency of the torque converter and transmission.

Finally, you may have a slipping torque converter. It would explain why the engine in the 1960 is working harder than the 1964. But change the fluid first.
Author:  Eatkinson [ Tue Jan 04, 2005 2:51 am ]
Post subject:  thanks, how...?
Thanks Bill. I do not know how old the transmission fluid is, and yes you're correct, i have not changed it recently. I will do that.

You're also probably right about the sound deadening materials - right now the valiant has next to none, with holes in the rusty floor, so I'm sure I'm hearing more transmission/engine noise just because of that than I would hear from my Dart with a solid floor and decent soundproofing material under a carpet.

However, how do I check for sure if the torque converter is slipping? The car doesn't slip in or out of gear, shifts fine through all speeds, and yet the engine sounds like it's running unduly fast at relatively low road speeds.

Thanks.

Evan
Author:  HyperValiant [ Tue Jan 04, 2005 8:11 pm ]
Post subject: 
It could also be dependent on what rear gear you have as to what the engine load sounds like,if your 60 has a lower gear( higher numerical ,very probible with the 170 as compared to the 225) it wil sound like it is revving higher.
HyperValiant
Author:  SlantSixDan [ Thu Jan 06, 2005 8:47 am ]
Post subject: 
HyperValiant is on the right track. The '60 Valiants came with 3.23 or 3.55 rear gears as stock. Most of the automatic cars got 3.23s, but some got 3.55s, either by special order or by factory decision (or by later replacement!). 3.55s, especially, will have that engine windin' way up on the highway.

The '64 Dart, on the other hand, has 2.93s.
Author:  Chuck [ Thu Jan 06, 2005 5:46 pm ]
Post subject: 
All of the 170s that I have seen came with at least a 3:23 rear ratio. This is about a 10.2% difference over the 2:93, so you can expect about 10% higher revs at the same speed as your Dart.
Author:  Eatkinson [ Thu Jan 06, 2005 11:14 pm ]
Post subject:  thanks - how come?
Thanks for the gear ratio information. That makes me ask - why would the engineers design a ratio that has the 170 torqued up high like that? The Dart is so much quieter at the same low 40 mph speeds, with not nearly the same engine-braking effect as the Valiant when you decelerate. Couldn't possibly have been for good fuel economy...was it for the resulting torque and more power they needed from the smaller engine?

thanks again.

Evan
Author:  Doctor Dodge [ Thu Jan 06, 2005 11:33 pm ]
Post subject: 
The 170 has a much shorter stroke and makes it's max. power / torque at a highr RPM, the engineers geared the rear end ratio lower to help keep the engine in it's "power band'.
DD
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