Transmission, drive shaft and differential question

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MorganKane

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Hi to all,

I recently bought -64 valiant with 170 slant six and manual three on tree tranny.
I start with most noticeable problem what is vibration in highway speeds.

I removed drive shaft (where trunnion boot is broken), and checked joints, front with needle ball bearings and rear u-joints
Surprisingly needle bearings and trunnion seems to be in good condition, there was plenty grease still inside even rubber boot was broken. I can't feel or see any wearness or gap neither front or read joints. So I am planning to replace only boot for now.

Then I opened diff cover. It has a big free play when I turn drive shaft. I noticed that play comes from little gears which move as much as 1-2 millimeters up in the axle when I turn drive shaft. So I think that I need to at least adjust gear play. Is there video or guide how to check and adjust/rebuild this diff (I believe it is 7.25 ?)

Last, I noticed that there possibly has been floor shifter because there is covered hole for it in bottom (see picture).
What kind of shifter and tranny would it have been?

Is it possible to put four speed manual there or even automatic transmission? Is there something that can just bolt in?

I am not big fan on this column shifter and non-syncroniced first gear, and my wife even less

Sorry if those questions are already asked and answered, I am new here and with this car.

IMG20231113183050.jpg
 
I don't know your year very well but it looks like a three and or 4 speed shifter opening.
 
It looks like the floor opening is oval shape like for 1966 & up boot, it also looks like you could change trans to updated 3 or 4 speed and go with a floor shifter.
 
moparlvr166 said:
It looks like the floor opening is oval shape like for 1966 & up boot, it also looks like you could change trans to updated 3 or 4 speed and go with a floor shifter.
Click to expand...
What are compatible trans types? Will they fit without modification to drive shaft or floor?
Thanks for helping beginner
 
A-230 3 speed with synchro in all forward gears, will need same bellhousing the A833 4speed trans uses.
Your 3-speed trans has a output flange with 4 bolts for ball and trunnion front joint driveline. You can find a 4 speed A833 with the same output flange, only made in 1964-65

You can upgrade to a front slip yoke for the A-230 and A833 trans or A833OD It looks like a A833 but has overdrive instead of 4th gear. If you use this OD trans, you will need a different bellhousing with a larger opening due to the larger front input bearing needed on this trans.
You can use the Search Forum tab on this site to look items up and get familiar with the options.
 
Why are we getting him off on a transmission tangent when he asked about the rear end? It normal for the rear differential to have play like that regarding the smaller pinion gears inside the case. A video would really help here, as we could tell if it is too much. I have a 64 Valiant with the original rear end and when I serviced it awhile back, it had some similar play, but three years and counting and it's fine. As long as they do not leak all the gear oil out, they will last virtually forever.
 
MorganKane said:
What are compatible trans types? Will they fit without modification to drive shaft or floor?
Thanks for helping beginner
Click to expand...
With your drive shaft, your choices are what you have now, OR the early A833 flange type four speed. But I don't think your vibration is your transmission. It is most likely the pinion angle had changed due to worn leaf springs or a bad transmission mount.
 
Hi Guys,

Thanks a lot for answers.

Sorry I was confusing you with different questions in same thread.

First, I don't think there is anything wrong with transmission, I just wanted to know if it is possible (quite easy way) to upgrade to floor shift trans, maybe fully synchroniced one. I dive in to this subject.
Is there automatic transmission what would fit? And if yes, will it need push buttons to dash or is there floor shifter option?

For vibration, I assumed that it would be caused by worn trunnion bearings as boot was broken. But there is no noticeable gap and I can't see any wearness in needle bearings. They still were holding grease and not dirty even boot was broken.

When car is cold, there is no vibration. But when I drive longer journey with higher speeds (50-60Mph), it slowly starts to vibrate.

Once I accelerated with full throttle in speed about 70Mph when it was vibrating and it suddenly kept loud rattling noise. I of cource released throttle and was sure that something went badly broken, but nothing. Driving with lower speeds is okay. Vibrating goes worse when speed increases, and car warms up. First 30-40 mails you cannot feel it at all.

Engine and trans mounts has just been replaced. Rear springs look okay, there is no broken leafs, but certainly rear of the car is quite low, so maybe springs have just worn out?

I will post video from rear end when I Am on the garage.
 
You started off correct in removing and checking the shaft

Have you tried reving the engine to simulate cruise speed, both in neutral with clutch engaged (foot off the pedal) and with clutch depressed? Might be engine/ belt/ accessory such as alternator

at what road speed does this occur? Is it possible, EG, that due to rear axle ratio and small tires, you are simply running on the highway at overly high engine RPM?

Also consider that sometimes something simple like an exhaust pipe rattling against some part of the vehicle can SEEM like a vibration, when it is only "that."

I assume you vigorously wiggled the pinion at the rear axle to feel for play in the bearings.

Also I had a strange vibration, with a swapped For 9" in my 67 Dart. In the end, it turned out that one of the differential side gears (spiders) had worn out the differential case in which it rides, and so the inboard (splined) end of the axle and the bearing were sloppy in there.
 
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