Hello everyone!! I have a question about the 4-speed transmission in my 1963 Impala. It is a Muncie transmission, but I would like to know if it is a M-22 or not. Cruising RPM at 60 mph is about 3000 with a 3:36 posi rear end. I read somewhere that with a M-22, there is not much of a RPM difference between 2nd and 3rd gear, which is true with me. Is there some numbers that I can look for or any telltale signs to look for? It won't make a difference with me one way or the other, just to satisfy my courisity. Thanks!!
Transmission ID
- Thread starter Impala Lover
- Start date
If its the factory, original trans in your 63 its not an M-22. Those weren't released until late 1965, I belive. Plus, the M-22s have quite a whine in first, second and third, due to the steeper angles of the gears. They were considered a close ratio trans and had a 2:20 fist gear and, like you described, they were pretty close between 2nd and third. What you most likely have in an M-21. It was a close ratio and had the same gear ratios, just not the same "rockcrusher" whine!
You might want to post the casting numbers off of the maincase and the tail housing. That will give you some where to start as far as identifying the year.
Ross
You might want to post the casting numbers off of the maincase and the tail housing. That will give you some where to start as far as identifying the year.
Ross
Actually the M21 has the "steeper" helix angle on its gears.That's why it's quieter than an M22 which has LESS helix angle ,but has a higher load capacity...It's a stronger tooth form but it's noisier. Only reason I know this is because I've been inspecting gears at gear shops the last 20 years.
the heavy duty M-20 and M-21 built from 1970-1974 also had the 26 spline input and t400 (32spline) output.
Thanks for all of the reply's!! I will crawl under the car and see if I can find some numbers. I will post the numbers when I can. By the way, this is not the orginal transmission. Thanks for the help!
Not all M-22s have the large output shaft (th400 style) The early M-22s had a 10 spline input shaft and a 27 spline output shaft. I'm not sure when the M-22s went to the fine spline input and large spline output.
You won't be able to tell if it's an M-20/21 or M-22 from the casting numbers. You'll have to pull the side cover and look at the angle of the gear teeth. As has been mentioned, the odds are you don't have a M-22. The main case casting number will tell you what year it is though. Also look for any stamped numbers on the main case and post those also. These will better help ID the trans.
You won't be able to tell if it's an M-20/21 or M-22 from the casting numbers. You'll have to pull the side cover and look at the angle of the gear teeth. As has been mentioned, the odds are you don't have a M-22. The main case casting number will tell you what year it is though. Also look for any stamped numbers on the main case and post those also. These will better help ID the trans.
muncie
Go to D & L transmission.com He is a 4 speed GODDDDDDD!!!!!!!!!
I rebuilt an M-21 that I thought was an M-22 but couldnt realy tell, I talked to him over the phone and after a few questions He Imediatly told me It was a late M-21 with a borgwarner gear set that some one installed at one time (supposedly BW made replacement gear sets for muncies at one time). I have delt with him MANY a time, He is truely a GOD in my book!!!!
Go to D & L transmission.com He is a 4 speed GODDDDDDD!!!!!!!!!
I rebuilt an M-21 that I thought was an M-22 but couldnt realy tell, I talked to him over the phone and after a few questions He Imediatly told me It was a late M-21 with a borgwarner gear set that some one installed at one time (supposedly BW made replacement gear sets for muncies at one time). I have delt with him MANY a time, He is truely a GOD in my book!!!!
