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[C2] Bang and Crunch Sound

 
Old 07-04-2019, 04:52 PM
  #61  
tuxnharley
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Originally Posted by 68hemi View Post
With those ratios a wide ratio trans will be better.
Originally Posted by AZDoug View Post


Doug
Yup, x2!
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Old 07-04-2019, 05:46 PM
  #62  
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Originally Posted by DansYellow66 View Post
Suggest having the transmission shop determine your rear ratio and also the transmission gear set (WR or CR). Locking it in first gear it will either take 2.2 turns of the input for 1 turn of the output (CR) or 2.5 turns of the input for 1 turn of the output (WR). If you really have a CR and 3.36 or higher rear, a wide ratio as suggested by others is probably a good choice. If your "big" engine is not too badly cammed (maybe a hydraulic roller?) and has good torque you can get by with a CR and 3.31 gears but around town it will take more than normal clutch slipping and care in getting away from a stop.

If you decide to invest some money in the transmission and build a WR one, I would recommend the Autogear M22W (wide ratio). The gears are made in Italy and are really nice.




I sort of splurged and used a new Autogear Supercase also.





Without looking up my invoice I think my parts bill for new case, rebuilt kit, new gear set, new bearing retainer, etc was around $1200. I worked with Larry at D&L Transmissions and he recommended re-using my tailhousing, mid-plate and side plate as long as they were in good condition. The Autogear tailhousing is noticeably bulkier and he said had been a little bit of an issue with Corvette tight tunnel clearances. It seemed like he said he had seen some issues with the billet mid-plates by Autogear but I know Paul's 5-speeds has developed a billet mid-plate also, and it looked really nice if one is needed. They are probably not an issue now.
This is absolutely the way to go with a big-inch engine that is use to its potential. New case, new gears, no headaches associated with worn and tired 50+ year old parts. As hard as these units are to R&R, and at this point in most of our lives, who needs the hassle of marginal/weak components?
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Old 07-11-2019, 08:57 PM
  #63  
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Okay, finally heard back from the transmission rebuilder. It is a close ratio and most of the parts are toast. He said he could turn it into a wide ratio, no extra cost, so I told him to go ahead. Going to be $1400 for the tranny, $600 uninstall/install.
My questions to you guys are, is there anything else different between the M20 & M21? How about the side case? Shifter linkage? Etc.?
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Old 07-11-2019, 09:02 PM
  #64  
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Let him fix what you have with the wide ratio change, I think you will be quite happy with that option especially on the highway.

Last edited by Pilot Dan; 07-11-2019 at 09:04 PM.
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Old 07-12-2019, 04:56 AM
  #65  
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Originally Posted by Pilot Dan View Post
Let him fix what you have with the wide ratio change, I think you will be quite happy with that option especially on the highway.
Dan:

Fourth is direct on all the boxes. Do you mean city driving?
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Old 07-12-2019, 07:05 AM
  #66  
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Originally Posted by 59BlueSilver View Post
Okay, finally heard back from the transmission rebuilder. It is a close ratio and most of the parts are toast. He said he could turn it into a wide ratio, no extra cost, so I told him to go ahead. Going to be $1400 for the tranny, $600 uninstall/install.
My questions to you guys are, is there anything else different between the M20 & M21? How about the side case? Shifter linkage? Etc.?
No - the gears are the only difference. Physically and operationally, everything else is the same. Do you know what gears he plans to use? I really recommend the Autogear M22W Italian gears like those in my pictures. The only real issue with a standard Muncie WR gear set is little too large of a gap between 3rd and 4th. I typically shift my engines up to the highest gear that I can roll along with w/o drama but at certain speeds I found 3rd was sounding like I could shift to 4th but if I shifted to 4th it felt like I was lugging the engine and I would go back to 3rd. The M22W slightly alters and closed up the 3rd and 4th gear ratios a little and seems to make the gaps between each gear more uniform. It's really the gearing that GM should have used. There is a bit more whine in the lower gears with the M22 pattern but I have found it to be pretty minor and seldom notice it (very loud sidepipes). I also suspect the Italian gears are better finished and may diminish some of the whine themselves. And they are stronger than the M21 and M20 standard gears. Ask DZAUTO (Tom) - I'm sure he would strongly recommend them.

There are also China (Korea??) gear sets around but with the Italian ones available I was told to avoid them.
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Old 07-12-2019, 01:09 PM
  #67  
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Originally Posted by Dan Hampton View Post
Dan:

Fourth is direct on all the boxes. Do you mean city driving?
Don,

He mentions in post #52 that he has a 3.08 or 3.36 rear in the car which is a nice combo with the wide ratio tranny if you cruise on the highway. The wide ratio makes for better overall driveability with the low rear going through the gears IMO.
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Old 07-14-2019, 07:36 AM
  #68  
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Another question, changing over to a wide ratio, how does that affect my speedometer readings? Before I was going 5mph faster than the speedometer showed.
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Old 07-14-2019, 07:37 AM
  #69  
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Originally Posted by 59BlueSilver View Post
Another question, changing over to a wide ratio, how does that affect my speedometer readings? Before I was going 5mph faster than the speedometer showed.
Not at all.
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Old 07-14-2019, 08:41 AM
  #70  
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Originally Posted by Pilot Dan View Post
Don,

He mentions in post #52 that he has a 3.08 or 3.36 rear in the car which is a nice combo with the wide ratio tranny if you cruise on the highway. The wide ratio makes for better overall driveability with the low rear going through the gears IMO.
There was no mention of overall in your past post---just highway driving. Thanks for clearing that up.
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Old 07-14-2019, 11:38 AM
  #71  
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Originally Posted by 59BlueSilver View Post
Another question, changing over to a wide ratio, how does that affect my speedometer readings? Before I was going 5mph faster than the speedometer showed.
As stated, not at all. You will still be going 5 mph faster than the speedometer shows if you make no changes to the speedometer driven gear. All stock 4 speeds have a 1:1 4th gear. So all will read the same MPH. What affects speedometer accuracy is final drive ratio of the rear end and rear tire diameter. I'm betting with your car indicating 5 mph slow, that you have tires about an inch taller than stock, or the wrong driven gear.
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Old 07-14-2019, 01:51 PM
  #72  
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I’m running 215/70R-15 (26.9 dia.) so should be compatible. Someone must have changed the gear. What color should it be, blue?
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Old 07-14-2019, 09:11 PM
  #73  
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Originally Posted by 59BlueSilver View Post
Iím running 215/70R-15 (26.9 dia.) so should be compatible. Someone must have changed the gear. What color should it be, blue?
With a 3.36:1 rear axle ratio and 27" tires, you need a 20-tooth (blue) speedo driven gear.
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