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Discussion Starter · #1 ·
Four speed transmissions are a great buy as they are still reasonable as well as durable, but in the past few years so many rebuilders have moved into this business it was only inevitable that some of them would cut corners to increase profits. How do I know this? I have seen it first hand since I have been in this business for over 35 years. In the past few years this has gotten a lot worse. A percentage of my business is in fixing or repairing mistakes that other transmission rebuilders make. I know this because guys bring me these transmissions to fix so that they work properly.
I wish that I could show you all the degree to which this problem of cutting corners, using worn out parts, and improperly rebuilding these transmissions is taking place in the market today. To begin with, the quality muncie used parts are in very short supply today. The reasons are manifold: The muncie transmission has not been offered by General Motors since 1974 and the parts went off the shelves in the 1990's. Since then folks have been hoarding parts causing a further short supply and driving the cost of parts up.
Recently a customer brought me a 1967 Muncie M-21, 2:20 ratio that he had purchased from a company in the mid west. He described several problems and told me he had paid $1200.00 for it. Upon a visual inspection the main drive gear was worn excessively on the very tip of the part that engages the pilot bearing. So I explained to him that the only fix was to replace the main drive gear. So I tore the box down in front of him and found an average rebuild. The new front bearing was a cheap 7 ball bearing. The original bearing was a 11 ball bearing, which is a big difference. The brass blocking rings were cheap cast rings rather than the good forged brass rings which will last twice as long. Next we discovered that the front aluminum case was bad. There is an area where the steel pin goes through the rear of the case and passes through 112 needle bearings and then entered the front of the aluminum case. At this point the fit should be so tight that it takes at least 12-16 whacks with a brass hammer to set this pin to the proper depth in the aluminum case. The hole for the steel pin was enlarged and needed to be bushed or the case replaced.
So now this poor fellow has $1200.00 in this box and now has to ante up money for a main drive gear, a front case, a small parts kit, a set of forged blocking rings and a new front and rear bearing. We also found a pair of bent scissors on the inside of the side cover. Oh yes he needed two new sliders. I have had two of these types muncies in my shop since the first of the year. (speed clutches). Lets not forget my fee to rebuild his box.
When you decide to look for a rebuilt muncie and see advs that say completely rebuilt $750.00 think about whether it is realistic to purchase a core and put new parts in it for that amount of money. A good core is $250-450.00, an american made master rebuild kit is $250.00, then if you have to put sliders in it or a case and finally add in your labor you are over the $750.00. So for these rebuilders to sell a trans at $750.00 the only way he can do it is with used parts. So buyer beware. How can a novice judge a muncie trans: The answer is........you can't by a visual or a promise from someone.
I am always ready to talk transmissons, drivelines and trans parts. Tech info is at N/C
Garys Gearbox 267 424 5838
 

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I appreciate the information Gary. I just purchased an M20 Muncie. I hope that it works ok. I'm going to install it into my 69 Camaro that currently has an M21. This will tell me 2 things.
1. To see if the M20 actually works like I was told.
2. To see if the gear ratio change warrants selling the M21 to fund another M20 for the old Camaro.

I hope not to need your services, but at least I know of a knowledgeable rebuilder here on Trifive.
Thanks, and take care. Jason
 

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Agree with everything you said Muncieman. These days I'd just as soon buy a complete new unit for $1700 from Paul at 5speeds.com..


New Super Case
New iron mid plate
New rollerized side cover
New Heavy Duty Tailhousing with line honed bushing
Torque locking sliders with matching hardened hubs
All new internals
Hex head sealing plugs
Forged synchro rings
Babbit and nitrided thrust washers.
Dynamic oil feed first gear sleeve
Sealed front bearing w/ std slinger nut design
Universal Shifter Shafts
 

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Totally unrelated, and not tri five, but it is always good to get advice from an expert.

I am giving serious thought about changing my 1981 corvette over to a manual from the current automatic as that is the one thing about my car that I have always disliked. If I do pursue this, it will be over the course of the winter when I am not rushed as the vette requires substantial dashboard disassembly and also the steering wheel removed to install the new pedal assembly.

I would like to install a Tremec 5-speed (or a Richmond 6 speed) but have not decided if I can justify the additional cost for a "week-end" car. If I decide to go Muncie, which one would you recommend? Do you sell rebuild transmissions?

I will need to start collecting everything for the conversion.
 

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Discussion Starter · #9 ·
Five or 6 speed

Totally unrelated, and not tri five, but it is always good to get advice from an expert.

I am giving serious thought about changing my 1981 corvette over to a manual from the current automatic as that is the one thing about my car that I have always disliked. If I do pursue this, it will be over the course of the winter when I am not rushed as the vette requires substantial dashboard disassembly and also the steering wheel removed to install the new pedal assembly.

I would like to install a Tremec 5-speed (or a Richmond 6 speed) but have not decided if I can justify the additional cost for a "week-end" car. If I decide to go Muncie, which one would you recommend? Do you sell rebuild transmissions?

I will need to start collecting everything for the conversion.
For myself having an overdrive gear for the highway is a necessity. So then you have the option of a 5 speed or 6 speed. With the 6 speed you get two overdrive gears which is really not necessary. (only one OD gear with the Richmond box). But if you are anything like me you look to the future when you might sell the car and with this in the future a 6 speed car seems to get more play. If I were you I would look to Keisler Engineering in Tennessee. They have a new killer 5 speed OD trans called a Super Sport 700 or 800. The numbers stand for the amount of torque and Horde power your trans can handle. They have a video and this trans is the real deal. Its a trans for the future. Defineately go with the Keisler Super Sport box over the Richmond box Gary
 

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Discussion Starter · #10 ·
Hi

I appreciate the information Gary. I just purchased an M20 Muncie. I hope that it works ok. I'm going to install it into my 69 Camaro that currently has an M21. This will tell me 2 things.
1. To see if the M20 actually works like I was told.
2. To see if the gear ratio change warrants selling the M21 to fund another M20 for the old Camaro.

I hope not to need your services, but at least I know of a knowledgeable rebuilder here on Trifive.
Thanks, and take care. Jason
I see that you are from Ohio. I lived in the Cincinnati Ohio area all my life until 4 and a half years ago. I had a great trans business there and was known as the Muncie man. There was always a crowd at my shopo on Fri evenings. I built a lot of transmissions there over the years. I am now neear Allentown Pa and it seems more difficuklt to get the word out here. The Trading Post magizine really helped me in Cinti but they don't have anything like that here but the car shows are huge. Good luck. I will be in Cinti the week of August 19th fore a visit

Garys Gearbox
 

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Discussion Starter · #11 ·
Hi

Agree with everything you said Muncieman. These days I'd just as soon buy a complete new unit for $1700 from Paul at 5speeds.com..


New Super Case
New iron mid plate
New rollerized side cover
New Heavy Duty Tailhousing with line honed bushing
Torque locking sliders with matching hardened hubs
All new internals
Hex head sealing plugs
Forged synchro rings
Babbit and nitrided thrust washers.
Dynamic oil feed first gear sleeve
Sealed front bearing w/ std slinger nut design
Universal Shifter Shafts
If Paul can sell those boxes at that price its only because he has a special relationship with George at Autop Gear. I had heard that he had some of the original blue prints for the muncie parts and then worked with Auto Gear. I cannot swear to this though

Garys Gearbox
 

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I’m about ready to pull the trigger on a new 4 speed trans. My set-up is SBC power, (375-385hp). My little motor has a good bit of cam lift (.530) and duration (310) so it likes to rev. Ford 9” rear with a 3.73 gear-set. Rear tires are 30.5 inches tall rolling diameter. I shift around 5.5-6K rpm so I don’t hurt the mouse.

What I think I have decided I need is a Muncie 4-speed. Looking at the Auto Gear / 5Speed.com set-ups. Below is a chart of their standard ratios.

M22W - DS 2.56 1.88 1.37 1.00
M22W 2.56 1.75 1.37 1.00
M22X 2.20 1.51 1.17 1.00
M22Z 2.98 2.04 1.47 1.00

I like the “Z” gear set with the exception of the 1st to 2nd bump (.94) seems a little steep to me, as compared to the .57 between 2nd and 3rd.

Seems someone running 1/8 mile sprints would be better off with a smaller bump between 1st and 2nd when torque is needed to get the load moving and then have a bigger bump between 2nd and 3rd after the load is rolling.

I think I want a M22Z gear-set but instead of a 2.04 second gear I want a 2.25 2nd.

Tell me where I’m messing up. Hell, I always mess up!
 

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Your general trend is right but you should be dividing instead of subtracting to compare the intermediate ratios.

For example with the 2.56 1.88 1.37 1.00 gearset you have 2.56/1.88 = 1.36 between 1st and 2nd. 2nd to 3rd is 1.88/1.37 = 1.37. 3rd to 4th is 1.37/1.00 = 1.37. That's the same rpm drop with each shift.

For the 2.56 1.75 1.37 1.00 gearset, the drops are 1.46, 1.28, and 1.37. A little mismatch there between 2nd and 3rd.

For the 2.98 2.04 1.47 1.00 gearset, the drops are 1.46, 1.39, and 1.47. Similar to the second example.

If your 2.98 gearset had a 2.25 2nd gear, it would be 1.32, 1.53, and 1.47.

Generally for acceleration performance, you can stand a bigger drop between 1st and 2nd, and you want the least drop between 3rd and 4th.

Also, the hardest shift to make (and the easiest one to miss) is the one with the highest rpm drop.

I'd rather see the 2.98 gearset have 2.98 2.04 1.39 1.00. Then the drops would be 1.47, 1.47, and 1.39.

The other part of the gear ratio selection is a bit more difficult. Because of how and where you drive, a certain 2nd or 3rd gear may suit your combination better. This is very related to the axle gear ratio, and how fast you're going when you downshift and want to accelerate. So it's overall gear ratio, low end torque, where and how you drive, etc.
 

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Thanks Rick, see I knew I was looking at something wrong. Looks like the folks who designed the "Z" gearset knew what they were doing after all!


I figure the 2.98 1st shoulld really help my hole shot compaired to a standard Munice M22 2.20 1st. while top end is un-affected.
 
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