i'm sure this is a common problem with 3rd gens, but i just wanted to get a solid answer. whenever i put my car from drive to reverse, or vise versa, i can hear a pretty loud bang, which sounds like the driveshaft moving back and forth.... the only thing i can think of is the rear being worn where the driveshaft goes in, so it has a lot more play than it should...... the rear on the car is very old, so is everything else.... any ideas??

 

u joints, trans mounts, you might want to get under the car and take a look at some of the parts

 

everything is new..... i really dont know what it is

 

try getting under the car and looking at the parts that might cause it

 

With the shift kit you have, it's going to grab pretty good when you drop it in gear! What idle speed do you have in neutral and drive? Factory idle speed is only supposed to be 450rpm in gear.
When I start my car even warm, I have to wait about 5 sec. for it to idle down before I put it in any gear.
One more thing, if you have much play in the yoke going on to the output shaft in the tail housing you would have a vibration starting about 45mph and would get worse as road speed increases. I recently had to replace my front yoke when I found the teeth in the yoke were starting to twist 3 in. inside where the output shaft ended inside the yoke (found a good one at the wrecking yard). Any amount of slop in the "yoke to output" shaft will accelerate wear of the tailshaft bushing and should be replaced with the instalation of the new yoke. Usually, if the bushing is starting to wear you will find trans fluid leaking around the rear trans seal.
If you need to fix it, I can give you an idea of the price if your mech. inclined!

1. used drive shaft and front yoke from the u-pull-it yard, 10.00
(worth the price just for the yoke)
2. tailshaft bushing 3 bucks
3. new rear seal 5 bucks
4. I borrowed a bushing removal and instalation tool from a local mech. (free) 350 TH tool will work on 700-R-4's.

The hardest part of the job was getting the old seal out. The bushing tool worked great and was actually easy! You could see wear in the bushing by the size of the dimples on the inside and when I mic'ed it I had only .009 difference from one side to the other but .009 at one end of a shaft will amplify at the other.

 

well, that sounds like it would work. i'm also concerned, i should be getting a 'like new' rear end soon to put into my car, do you think this will solve the problem i'm having? i'm guessing it would, considering all the things you've said involve changing things in the actual rear end itself. thanks.

 

sounds like the u joint to me

 

u joint?

 

If you think that anything I said had anything to do with the rear end (differential?) there's no hope for you! Take your car to a transmission shop and get a free inspection and analisis.
They will drive your car and tell you if you have a problem or just need minor adjustments. This shouldn't cost you anything and you can get a proffesional opinion directing you to the exact problem if you have one. You can always say thanks, and decline the repair if it seems excesive till you have more money for the work! Good luck!

 

i dunno about taking it to a tranny shop..... i figured someone would have had the same problem, and they could give me an idea of how they fixed it

 

scroll up several people here did tell you how they fixed it

 

Get two new universal joints from local parts store. Pick up a Chiltons or Haynes book...either is adequate for a how to on this. Remove the two ubolts at the connection to the rearend..pull the driveshaft out. Hammer and 5/8ths socket to drive the old u-joints out if memory is accurate. Read the page in the book you got and it is a simple job and a good place to start learning. To drive an older car one needs a fat wallet or some wrenchnig skills....most important is safety....get two sturdy jack stands with the book and USE them. NEVER EVER get under a car supported by the jack only.

 

Your memory is accurate, for 1970! You can beat that U-Joint till your fingers turn blue and all your going to get for your effort is a smashed up 5/8 socket.

 

Sorry that you don't agree but I don't recall a ruined socket and for sure there were no mashed fingers or other destroyed hardware. I don't have a vise nor need one often enough to purchase and find a place to put it and going elsewhere to have it pressed is ridiclous.

Quote:
"1. used drive shaft and front yoke from the u-pull-it yard, 10.00
(worth the price just for the yoke)
2. tailshaft bushing 3 bucks
3. new rear seal 5 bucks
4. I borrowed a bushing removal and instalation tool from a local mech. (free) 350 TH tool will work on 700-R-4's."

I sure hope that drive shaft from the yard has good universal jonts! Cause he surely must not need to worry about them as you offered him no better option than my socket and hammer.

Oh lest I forget ty for the feed back, Einstein....I'm a jerk have a lovely day.

 

No need to get testy my man! There's just a better way. Yes the U-joints were good in the used drive shaft. You don't need a vise to remove the old u-joints, just a torch. The first time I tried to remove the factory installed u-joint where they used sealed joints, I destroyed 2 or 3 sockets before a friend showed me what was going on. We took the shaft outside and heated them up and BLAMO! You know, Einstien wasn't born a gienius, he still had to learn. Fortunatly he chose to share his learning's!
For someone who has never used a torch on u-joints I wouldn't recomend it for a first timer. It would be wise to have someone who has done it before show you how. And by all means, use safety glasses!