Tranny troubles

[Belair348]

Hey,

I finally got up the gumption to have a 700R4 put in my 58 this Spring. Well after weeks of waiting I finally got it back only to find that the drive angles are wrong. Whenever I take off I get a big clunk. Well, due to work, vacations, the Hades like heat, and all the other crap that can happen during the summer, I'm finally taking it back to the shop on Thursday.
Here's my question. Can anyone tell me in the ballpark what the correct driveshaft angle should be from the carrier bearing to the rear of the transmission for a 1958 Belair 348 / 700R4 setup ? I can't go by the manual since the driveshaft is shorter.

Also, I used the bowtie overdrive cross member, but the shop says it was impossible to install it the way that bowtie says to do it. So they created a spacer to level out the tranny. Has anyone else installed one of these, and did you have to bang out the tunnel to get it to work?

Thanks for the help

 

[mac1]

It may not be the ds angle. The first ujoint is very close to the parking brake cross shaft with a 700 r4 and might be coming into contact with it. Also check and see if the ds enters the tunnel more or less in the center of the opening. You can experiment by raising and lowering the trans using shims. I would also recommend checking the carrier bearing assembly. Sometimes the rubber boot pops out of the housing and makes the clunking sound you are describing.
Here are some pictures of a 700r4 behind a 327. Good luck, Mac

 

[Belair348]

Mac,

Thanks for the work to get those pics. I see you have your bowtie cross member installed in the bottom holes, they say it's supposed to be in the top holes. SO apparently it will work on someone's car. I saw how close the PB assembly was to the U-Joint but I was thinking that there shouldn't be that much movement in the driveshaft assembly to hit it. I'm going to take the PB assembly off and try it. It'd be great if that's really what it was. Also, I assume you're using a rubber boot carrier bearing? I see the hard plastic ones advertised and was thinking that if the drive shaft assembly is moving that much, it might eliminate it.

 

[409newby]

I've had a few cars that the slipyoke would hang up when first starting out from a start then free itself causing a clunk and a dropping of the rearend, this usually only is with a new yoke, as it wears it gets better.

 

[Belair348]

OK, flipping the PB assembly over seems to have made that sound go away, now I'm hearing something in the rear end. This is a new 348 (3x2) pulling about 325 hp, not alot but it's a hell of a lot more than the 283 had. I'm getting the clunking sound only under hard acceleration from a stop. Could the rear end be trying to twist down and that's causing the rear U joint to chatter?

 

[mac1]

Mac,

Thanks for the work to get those pics. I see you have your bowtie cross member installed in the bottom holes, they say it's supposed to be in the top holes. SO apparently it will work on someone's car. I saw how close the PB assembly was to the U-Joint but I was thinking that there shouldn't be that much movement in the driveshaft assembly to hit it. I'm going to take the PB assembly off and try it. It'd be great if that's really what it was. Also, I assume you're using a rubber boot carrier bearing? I see the hard plastic ones advertised and was thinking that if the drive shaft assembly is moving that much, it might eliminate it.

Bowtie Overdrive installed this transmission back in 2003 and this is where they installed the crossmember. I now use the standard CB assembly and an inland empire sliding rear DS. I tried using the inland empire neopreme HD CB assembly but I had this continuous whining sound that drove me crazy so out it went. Glad you got rid of that sound. I'm no expert on rear ends but maybe Tom Parsons will chime in. You might need a fluid change. That would be 90 wt gear oil. Mac

 

[Belair348]

Mac,

OK, the noise is not from the rearend. I had a buddy ride in the back and it's from the CB tunnel. Looked up into the tunnel and I can see where the U-Joints are actually contacting the tunnel. In looking at it, it almost appears that the rear end, CB, and tranny are not in alignment. As I said before I'm taking it back on Friday to see if they can straighten out the issue (pardon the pun). I just find it hard to believe that the CB is still in one piece and the driveshaft is moving that far, but it is.

Thanks for the advise and information.

 

[boxerdog]

Where is that thread that went through all of the driveshaft angles??? I know I lowered my CB (machined base of aluminum one) to help correct the angle change caused by the longer 700r4 tranny...but that would depend on the crossmember too.

 

[models916]

You have to lower the center bearing by about 1/2 inch to get the angles anywhere near correct. The 700R4 is so much longer than stock it changes everything. What I did is lower center bearing .5 inch. Put 0 angle on the front driveshaft to trans output shaft. Make pinion shaft the same angle as trans output shaft.

 

[Carmine]

It may not be the ds angle. The first ujoint is very close to the parking brake cross shaft with a 700 r4 and might be coming into contact with it. Also check and see if the ds enters the tunnel more or less in the center of the opening. You can experiment by raising and lowering the trans using shims. I would also recommend checking the carrier bearing assembly. Sometimes the rubber boot pops out of the housing and makes the clunking sound you are describing.
Here are some pictures of a 700r4 behind a 327. Good luck, Mac

I don't mean to steal this thread, but in your 2nd pic, I see what I think is your speedometer cable hooked up and there is something else also attached. Did you attach this cable to your stock in dash speedometer?? How did you mate the two?? What parts were used?? Thanx, Carmine.

 

[models916]

I shortened the parking brake rod on mine so the cross bar sits lower. Just cut it off and cotter pin it top and bottom so it floats in there. Mine has a spring instead of that rubber piece. My starting point is to place the car on the ground at ride height. Angle the engine so the carb pad on the intake is level or 0 degrees, shimmed at the trans mount. Shorten the center bearing to get as close to 0 degrees on the trans to front driveshaft as possible. Angle the rear differential pinion to the same angle as the transmission output shaft. If you are using the stock center bearing mount, not much you can do about it.

 

[valvefloat]

WOW! I never would have guess there could be so much trouble with a drive shaft. I fabbed my own crossmember 8 years ago. Has worked pretty well. I'd be happy to post any pics with any measurements.to help. I felt it was a tight fit. Like Models says, its a long trans. I do not know my drive train angle.

 

[models916]

The bigger gears have more problems as the driveshaft spins much faster. The 4:10 could be felt at 60 mph and up, the 4:88 was impossible to live with. I went to a 1 piece shaft.