4 speed driving?

[jerrysdustydog]

I need some feedback from original roadrunner owners with the A833 tranny. I believe I have a 491 8 3/4, but not a sure grip. As some of you know, I just got all my issues resolved and got to drive the car finally. I have only put 6 or 8 miles on it, but have noticed that first gear feels alot like 2nd should. Very tall, but when shifting into 2nd or 3rd it seems normla, just getting it up to 10 or 15 miles an hour is tougher than it should be. Are all 1st gears that high in ratio? I have not looked at the transmission specs to see what ratio they should be, but wonder if someone may have changed the gear out. I have got the car up to 70 or so and it does wind out, but no tach to see what it's actually turning. I guess depending on what you guys say, I will verify the rear end ratio, and maybe add a tach to see what it's doing. I may have to go back into the timing chain, for the guy that helped me build my engine may have not got the "marks" lined up on the gears correctly (what I get for letting someone else do it). Engine does not sound 'right', and sure doesn't feel like it has the power it should. The car kinda acts like it has the power of a 350 chevy with a 2 barrel. Yeah, it never ends.

 

[Big John]

Check the linkage. Maybe you are in third gear instead of first.

 

[69hemibeep]

I'm with John on the linkage and the video you posted I think last week the engine had a funny popping going on. Timing or firing order?

 

[69hemibeep]

Getting any rain yet?

 

[moparmonk]

While it shouldn't make a difference in First or Second, check to make sure the shift arms (not the rods to the shifter) coming directly off the transmission are both the same direction.... Not one up and one down. (both up or both down, I can't remember) That was a trick I believe MaMopar started in 74 to make the Overdrive version of the 833. In other words 4th gear location became 3rd gear and 3rd gear became "overdrive" due to clearance locations in the case for the bigger gear. Just food for thought. Solve your motor issue first and the rest will come to you.

 

[Bee Keeper]

Hard to diagnose without knowing your rear end ratio and engine rpm's, but checking the shifter linkage is definitely the place to start.

For what it's worth, I'm running 391's with the same 4 speed and I have no problem taking off in second gear.

 

[jerrysdustydog]

No John, it's definately not 3rd, the shifting sequence feels right once you go through the gears (all 4) with each shift dropping the rpms as they should, just not near low enough in 1st. I know the original owner used to run a different rear end at the track, and who knows what has been done with the tranny over the past 40 years.
Yes Bob, rained on me this morning all the way from Williams to Gallup. Just slow and steady with lots of water standing along the way. No miss at all in the engine, just doesn't sound correct and everything points to the timing chain being off. Just not off enough to cause backfiring through the carb or exhaust. Maybe a tooth or two? Guess I'll find out when I have the time.

 

[moparmonk]

Lift the car up from the back and count the drive shaft revolutions. Put a white out mark on the tail housing and the front u joint. If it is a "1 legger", have someone on each side of the car turning the wheels in the same directions and count the revolutions of the shaft. (way easier with a sure-grip) 2 and 3/4 turns will be 2.76 ratio. 3 1/4 turns would be 3.23 ratio which was very common. 3 1/2 turns would be 3.55 Almost 4 turns??? You guessed it! 3.91's Over 4? I wont even ask because the first 4 gear runner with 4.10's I tried with a stock 383, I started out in 3rd gear and thought I was in first. By your description, you clearly appear to not have that issue! LOL! That will teach me to learn a standard on a Toyota Corolla! Or you could check the tag on the rear end but if they have been changed, not so much!

 

[jerrysdustydog]

Yeah, tag is long gone. This car came with a 3.23 sure grip originally, was changed to an A-body 391 sure grip at some point for the track use with wrinkle tires, and when I got it, someone had put a open diff. rear in it. Yeah I will check it out closer this time. thanks!

 

[jerrysdustydog]

Looks like I have found the problem. I jacked up one side of the rear, rotated the wheel 1 revolution and the drive shaft turned 2 1/4 times. Yeah, no wonder I had problems taking off.

 

[moparmonk]

I am glad you responded but do have a question. If you leave one tire on the ground, I think that the spider gears in the rear end will also spin. That is why both wheels have to spin together. (theoretically) with one wheel fixed, it should turn 1/2 of what it should. I guess I would leave the car on the ground and roll it in the driveway stopping and watching for one complete turn of the tires. Strap your camera under it and video the revolutions. This may be more accurarte but it sure sounds like your in the 2.76 range. Anyone know of anything higher for an 8 3/4?

 

[jerrysdustydog]

OK, now I'm really confused, I marked the tire rolled the car forward and counted the revolutions of the drive shaft. I did it twice just to be sure, but it came out just over 4 complete revolutions of the drive shaft for one complete revolution of the wheel/tire. This goes along with what the owner told me that it had a 3.91. But, still why so high when I take off? Will look at getting a tach put in the car and check each gear/mph/per RPM to see what the hell is going on. Surely no one re-geared the tranny.

 

[moparmonk]

Thanks for the update! I guess I may be confused as if it went more than four turns, and you think 3.91? My Guess would of been 4.10's. Let's add some more questions. Most birds I believe came with 14 inch wheels. Does yours have low profile tires? I think only the A-12 cars got 15 inch wheels. Anyone else have more info on this? Also, since you had a gear change, maybe the speedometer pinion in your transmission is stock and not changed to the gear ratio you have. They are color coded with different number and different pitch on the teeth to coincide with the gear ratio you have. I think the service manual has what color to what gear ratio. Another thought was these cars had 120 MPH and 150 MPH speedometers. Maybe that was changed? Not sure if they are calibrated different. I guess you could pull the wheels and use the drums instead of the wheels but it would be hard to have them synced as if they were on the ground. I am digging here but trying to help!

 

[69hemibeep]

Jerry it seems you have a 4;10 or 3;91 I don't understand the first gear issue unless the cam is off. As far as tire size it won't make that much difference in first gear Hemis and A12s came with 15" tires and the GTX had the 150mph Speedo

 

[jerrysdustydog]

Bob, I am going to have to dig into this a bit. No, the engine does not sound "right", also has no power to speak of. I need a real Mopar guy to help with tuning, and it might just be the cam is off as you stated. Did drive the car 6 miles into town (Williams) last weekend, tends to run hot at an idle even with a huge aluminum radiator. Have carb issues as well to deal with, and may pull off the edelbrock and and try to make the 750 Holley work. It does appear to be over 4:1 to me and might be 4.10, as it does wind up going down the highway, maybe 55 to 60 MPH is winding up to 3 grand or so, still don't have a tach. Maybe gonna be a long winter. To top it off, leaks out the front valley pan area, going to order a new one to stop that. I did advance the timing some and didn't seem to make much difference.