Because different transmission gear ratios can greatly affect a drivetrain combination, it’s important for anyone performing a transmission swap to know the gear ratios of the gearboxes you might be installing in your vehicle.
We’ve assembled a variety of manual gear ratio charts for General Motors vehicles that we hope can help you avoid choosing the wrong transmission only to discover your hot rod or truck is performing like a 19th-century horse-drawn chuckwagon, minus the delicous beans and salt pork.
Planning a manual transmission swap in your Chevy or GM vehicle? Double-check your gear ratios. Here’s a good start.
This Sting Ray’s Muncie M21 is connected to a super-cool Hurst reverse lockout lever poking through the boot. (Image/George Lyons)
[NOTE: Not every transmission in GM’s history is listed here. It is mostly Camaro/Firebird/Corvette-focused. We’re sorry if you love a particular transmission not shown on this list. We promise it wasn’t intended as any sort of slight to the excluded GM-made transmissions.]
I ran a M-21 in my Big block Chevelle with 3:55 gears. Great torque. I was shifting into 3rd around town. I then swapped a 454 in and I run an M-20 and it is much better all around. Great low but not so great highway speed. 3500 T 65 mph or so. Gear Venders is in the future
Why not just get TALLER tires?
According to what you wrote, your tires are only about 22″ tall.
That’s pretty short.
P245/60-14’s would drop your engine rpm (@ 65 mph) by around 500 rpm’s.
…either that or you need your tach recalibrated.
I run a BB 454/425 with Ford 9” rear at 3:89. But I use the ZF Black tag early helical gears ( not straight cut of later design) 6spd @ 65mph tachs 1521 rpm’s Vehicle is a 1934 Ford pickup weight 3800# It also runs the real good on the non ethanol gas
Then someone jury rigged it in there.
NEVER seen a spec showing the Ford T&C in a mid size GM vehicle.
Base tranny for GM early 70’s would be the Saginaw.
If you mean the 4-spd overdrive, I believe the ratios were 3.29, 1.67, 1, .81 with the older cast iron box.
The newer aluminum cased one was similar; 3.25, ?, 1, .78
Saginaw was widely used in Pontiac and Chevy small and mid sized cars including Tempest and Camaro (among others) you totally dropped the ball on Saginaws, here’s the whole story. Saginaw 3-speed
Apparently they did, because I have an issue of a rare “Diesel enthusiast” magazine called “Diesel Digest” and it mentions the new 6.2L GM diesel engine in a 1981(?) issue and the tranny listed for the truck is the A833.
It is a rare application, though. I think I’ve ever only seen one truck that was equipped as such.
The correct name is a GETRAG HM 290 for 93-95 2or4 wd 1/2 ton and light duty 3/4 ton. The S series V 6 used the NV 3500. The NV4500 was in HD 3/4 and 1 ton application.
Hey Greg, as long as it’s stock, it’s pretty straightforward. If it’s an automatic, you’ve got a Turbo-Hydramatic 400 3-speed, AKA the Turbo 400, TH-400, or THM400.
…
If you’ve got a manual transmission, we’re assuming it’s a four speed, because (from what we can tell) Chevy dropped the base manual 3-speed after 1969.
…
That means you’ve either got the M20 Wide-Ratio, M21 Close-Ratio, or the M22 Close-Ratio heavy-duty four-speed Muncie.
…
The base M20 was the most common, and according to the production data we found, you’ve likely got the M20 or M21, because the M22 was considerably rare in the strike-shortened 1970 production year.
…
So how do you tell if it’s an M20 or M21? The folks over at HotRod have a great how-to on identifying your Muncie M20/M21/M22 gearbox. Check it out here.
…
Hope this helps!
I am planning to get an MM88 Getrag 7 Speed manual transmission and put it in my Colorado pickup truck. Does anybody know where to purchase this transmission? They are found in the Bronco, but i need an aftermarket one.
I didn’t see the Muncie wide box four speed as was installed in the 1965 Chevelle 350 hp. 327 cars.
I ran a M-21 in my Big block Chevelle with 3:55 gears. Great torque. I was shifting into 3rd around town. I then swapped a 454 in and I run an M-20 and it is much better all around. Great low but not so great highway speed. 3500 T 65 mph or so. Gear Venders is in the future
Why not just get TALLER tires?
According to what you wrote, your tires are only about 22″ tall.
That’s pretty short.
P245/60-14’s would drop your engine rpm (@ 65 mph) by around 500 rpm’s.
…either that or you need your tach recalibrated.
I run a BB 454/425 with Ford 9” rear at 3:89. But I use the ZF Black tag early helical gears ( not straight cut of later design) 6spd @ 65mph tachs 1521 rpm’s Vehicle is a 1934 Ford pickup weight 3800# It also runs the real good on the non ethanol gas
How about the T&C HD 3-speed – yes, a Ford box, which was the base transmission in pretty much every GM musclecar? 1970 Buick GS455 had it…
Then someone jury rigged it in there.
NEVER seen a spec showing the Ford T&C in a mid size GM vehicle.
Base tranny for GM early 70’s would be the Saginaw.
Dearborn 3speed is the nomenclature.Ford 3.03
If you mean the 4-spd overdrive, I believe the ratios were 3.29, 1.67, 1, .81 with the older cast iron box.
The newer aluminum cased one was similar; 3.25, ?, 1, .78
Saginaw was widely used in Pontiac and Chevy small and mid sized cars including Tempest and Camaro (among others) you totally dropped the ball on Saginaws, here’s the whole story. Saginaw 3-speed
No Lines (grooves)
2.85
1.68
1.00
1 Line
2.54
1.50
1.00
2 Lines
3.11
1.84
1.00
3 Lines
3.50
1.89
1.00
Saginaw 4-speed
No lines
2.84
2.01
1.35
1.00
1 Line
2.54
1.80
1.44
1.00
2 Lines
3.11
2.20
1.47
1.00
3 Lines
3.50
2.47
1.65
1.00
Read more: Transmission Ratios Chart http://www.roadkillcustoms.com/hot-rods-rat-rods/garage-shop-reference-Transmission-Ratios.asp#ixzz4wwRJejBN
The “no groove” 3-speed was the standard truck tranny in the 70’s.
The “1 groove” 3-speed was the standard car tranny in the 70’s.
Hi there
Are you aware if Chevy 1/2 ton trucks from 1980 to about 1985 were fitted with overdrive A833 New Process transmissions?
Thanks
Apparently they did, because I have an issue of a rare “Diesel enthusiast” magazine called “Diesel Digest” and it mentions the new 6.2L GM diesel engine in a 1981(?) issue and the tranny listed for the truck is the A833.
It is a rare application, though. I think I’ve ever only seen one truck that was equipped as such.
Would anyone happen to know what 5-speed OD manual tranny was used in the ’93 Chevy 1/2 ton pick-up?
NVG 4500 I think, made in same plant as the “Muncie 4 speed” back in the day.
“NVG” stands for “New Venture Gear”.
It is the successor to the old “New Process” gear company.
Nv 3500 1/2 ton nv4500 3/4 1 tom
Fred that would be a HM290 trans if it was a V-8 and a smaller version for the 4.3 L V-6. Hope that helps.
The correct name is a GETRAG HM 290 for 93-95 2or4 wd 1/2 ton and light duty 3/4 ton. The S series V 6 used the NV 3500. The NV4500 was in HD 3/4 and 1 ton application.
How do I tell what transmition is in my 1970 Corvette stingray?
Hey Greg, as long as it’s stock, it’s pretty straightforward. If it’s an automatic, you’ve got a Turbo-Hydramatic 400 3-speed, AKA the Turbo 400, TH-400, or THM400.
…
If you’ve got a manual transmission, we’re assuming it’s a four speed, because (from what we can tell) Chevy dropped the base manual 3-speed after 1969.
…
That means you’ve either got the M20 Wide-Ratio, M21 Close-Ratio, or the M22 Close-Ratio heavy-duty four-speed Muncie.
…
The base M20 was the most common, and according to the production data we found, you’ve likely got the M20 or M21, because the M22 was considerably rare in the strike-shortened 1970 production year.
…
So how do you tell if it’s an M20 or M21? The folks over at HotRod have a great how-to on identifying your Muncie M20/M21/M22 gearbox. Check it out here.
…
Hope this helps!
Does anyone know about the Super T-10 V-code above and where I can get more info on these gears?
Would be appreciated.
Mark
I am planning to get an MM88 Getrag 7 Speed manual transmission and put it in my Colorado pickup truck. Does anybody know where to purchase this transmission? They are found in the Bronco, but i need an aftermarket one.