Transmissions

Transmission archives.

Manual trans gear ratios and teeth counts.

Post Admin Today at 4:28 am
Manual trans gear ratios and teeth counts.
A833 RATIOS FINE PITCH GEARS

SMALL SPLINE 2.66 1.91 1.39 1.00
70 AND EARLIER

SMALL SPLINE
'70 T/A '74 - '74 2.47 1.77 1.34 1.00

'65 6CYL &
'74 - '75 318 3.09 1.92 1.40 1.00

'75 - '80 O.D. 3.09 1.67 1.00 0.73

COARSE PITCH GEARS

LARGE SPLINE
'70 AND EARLIER 2.65 1.93 1.39 1.00

LARGE SPLINE
'71 - '74 2.44 1.77 1.34 1.00

RACE RED STRIPE
GEAR SETS 2.65 1.64 1.19 1.00

GEAR TEETH COUNT

LOW GEAR RATIOS............D/P..........MAIN SHAFT GEARS
...................................GEAR..........3 RD.....2ND......1ST
2.44..............................22.............2 6.......30........33
2.47..............................25.............2 9.......34........35
2.65..............................21.............2 6.......30........33
2.66..............................24.............2 9.......34........35
3.09..............................22.............2 7.......32........35
2.65 RED STRIPE.............21.............24.......28..... ....33
3.09 O.D........................22.............18 O.D..30........35

LOW GEAR RATIOS..........DIRECT.......COUNTER SHAFT GEARS
.................................................. .3RD......2ND.......1ST
2.44..............................26.............2 3.......20.........16
2.47..............................30.............2 6.......23.........17
2.65..............................27.............2 4.......20.........16
2.66..............................31.............2 7.......23.........17
3.09..............................33.............2 9.......25.........17
2.65 RED STRIPE..............27.............26.......22.... .....16
3.09 O.D........................33.............37...... .27.........17

...3 SPD..............1ST....2ND....3RD
- '72 A903..........2.95....1.83....1.00
.........................3.22....1.84....1.00
'73 & UP A250......3.18....1.83....1.00
SLANT SIX ONLY

'73 & UP A230.....2.55....1.49....1.00
V8 AND SLANT 6..3.08....1.70....1.00

NP 2500 DAKOTA 5SPD
1ST......2ND.....3RD.....4TH.....5TH O.D.....REV.
3.79.....2.29....1.48....1.00.......0.79........3. 90
Tell everyone to join our forum, today!! Have fun and enjoy.

www.moparperformancechat.forumotion.net

To calculate the correct speedometer pinion to match your gear and tire combo so the speedometer will read properly, but follow the match equation below and pick the correct speedometer pinion gear from the list below.

((63360/tire circumference)*gear ratio)/76.3 = number of speedometer gear teeth

tire circumference = tire diameter * PI(3.14159)

You should round the number of teeth to the nearest whole number. If you round down, the speedometer will read a little fast. If you round up, the speedometer will read a little slow.


TOOTH COLOR PN#

24 ... WHITE 3410024
25 ... BLUE 3410025
26 ... RED 2538926
27 ... WHITE 52068149
28 ... BLUE 52068150
29 ... BLACK 52068151
30 ... YELLOW 52068152
31 ... GREEN 52068153
32 ... BLACK 52068154
33 ... YELLOW 52068155
34 ... GREEN 52068156
35 ... ORANGE 52068157
36 ... RED 52068158
37 ... WHITE 52068159
38 ... BLUE 52068060
39 ... GREEN 52068061
40 ... ORANGE 52068062
41 ... RED 2538941
42 ... WHITE 2538942
43 ... BLUE 2538943
44 ... BLACK 2538944
45 ... Yellow 2538945

The small block bell housings and small block A904 and A727's will fit the following blocks.

273
318
340
360
3.9 V6
5.2
5.9

They will also fit the 4.7 and 5.7 Hemi with this one distinction.All of the bolts holes line up except the one in the 3 o'clock position. It's about a half inch off. If need be, it can be modified so ALL of the bolts fit. Otherwise, just leave it out. IT does not effect the alignment of the torque converter or clutch assembly.

Will an A500 or 518 fit in a car?

First off I would never use the A500. It is the weakest of the o.d. transmissions. And in a simple word, the A518 wont fit. It's too wide for the standard transmission tunnel and frame. To force it to fit would require mounted the car on a frame machine in a body shop and cutting, notching, plating and reinforcing the frame work in the transmission tunnel area. The transmission tunnel would also require a cut down the center and a wider piece of sheet metal installed. Not only does this lower the value of the car, if the frame work is not done correctly, you'll end up with a car that the doors wont open and close properly.

Now if you had a truck with a standard transmission or 3 spd auto you could swap in an A518. You would need an early model without the electronics. You would have to run a switched wire to the o.d. solenoid and manually shift it to o.d. every time you needed it. Towing capacity would be effected as well. The A518 cannot take the heat and abuse of the other 3 spd auto's. You cannot tow with the o.d. turned on or you will destroy the o.d. unit. IT does not have enough clutches to hold sufficiently to tow a load.

If you just had to have an o.d. transmission in a truck or a car I would go with the A833 4spd. o.d. units from the mid '70's till the late '80's. That would be your best option for the money and it's a complete bolts in. The swap can be done in just a few hours even by an armature.

The A833 4spd.

Chrysler began using "833" four speeds in passenger cars in 1964. The transmission was designed by Chrysler and manufactured by New Process Gear Co. Chrysler installed the 833 four speed behind the Slant Six and every V8 produced up till the late '80's.

How 833 Four Speeds Differ

There are several characteristics of the various A-833s that determine which four speeds fit in which chassis and with which engines. For the passenger cars, Chrysler manufactured two different length four speeds. The A/F-bodies received a short tailshaft A-833 and the B/C/E-bodies received a long tailshaft A-833. The short A/F-body tailshaft places the shifter pad behind the cross member mounting . The "shifter pad" is the 3 bolt bosses set in a triangle shaped pattern on the side of the tailshaft and servers as the mounting point for the shifter. A/F-body 4 speeds have only one shifter pad. The 1964-1969 B/C-body A-833s place the shifter pad ahead of the cross member mount flange, and the 1970-74 B/E-body long tail housing four speed has two shifter pads, one ahead of the cross member mount flange for B-bodies, and one behind the the cross member mount flange at the very end of the longer B/E tailshaft housing and this position is used in E-bodies.

The tail shaft length is the most apparent at first glance. Perhaps the most troubling is the diameter of the Input Bearing Retainer that is located on the front of the four speed and fits into the large hole in the back of the bell housing. There were three different sizes on production four speeds. There was the 5.125" dia. used on the 1975 and later Overdrive units, the 4.80" dia. used on "Hemi" transmissions, and a 4.35" dia. used on everything else. The 4.80" Hemi units are also known for their special course cut gears, 18-spline input shaft, larger input bearing, and the requirement of a larger clutch release bearing. Calling it a Hemi unit is not entirely correct, the 18 spline units were also used in most 440 6 pack applications as well. Hemi units are rare compared to the regular 23 spline four speeds, however there are generally a few floating around at most major swap meets or you can order one up from Passon Performance.

With any transmission swap, the drive shaft type and length must be carefully observed and adapted to the vehicle.

For the "early" 1964-1965 A-833s, both the A-body and the B/C-body units used the ball & trunnion output flange type. All later 66 & up A-833s were slip yoke types. The ball & trunnion 4-speeds are easily identified by the four bolt non-sliding flange attached with a large nut on the end of the thicker cast iron tailshaft. The larger tail housing allows room for a third ball bearing at the rear of this 833, making it a very strong and stable gearbox. Even with this added bearing, this trans. should probably be avoided by anyone who doesn't have a 1965 or earlier car or isn't prepared for the challenge of shortening a ball & trunnion drive shaft or locating the B & T replacement parts. I picked up a rebuild kit for ball and trunnion drive shafts from my local NAPA stores. They are easy to install and they are actually the precursor to the CV joints that are used today. Ball and trunnions use a two bearing set up where as the cv joints use three bearings and a tri pod device.

Gear Ratios

There were several gear sets used in production 833 four speeds. Below is a list of the most common gear sets:

(Year and Application 1st - 2nd - 3rd - 4th)
More on 833 ratios and applications (Click Here)

1964 thru midyear 1966 A-body 3.09:1 - 1.92:1 - 1.40:1 - 1:1 = G/RG and LA engines. (These all used a 4.35" IBR.)

1964 thru 1970 B/RB engine 2.66:1 - 1.91:1 - 1.39:1 - 1:1 = (The "close ratio" V8 gearbox)

1970 T/A & AAR 340s 2.47:1 - 1.77:1 - 1.34:1 - 1:1, = 1970 thru 1974 high performance
(A 2.44 first gear was also produced in this time period and some units had 1.91:1 second gears.)

1975 thru 1987 Overdrive 3.09:1 - 1.67:1 - 1:1 - 0.73:1 (Trucks used a 0.71:1 fourth)

The Overdrive four speed was a regular A-833. The shift lever on the side cover was flipped over and the gears were swapped on the shafts to get the o.d. ratios. You can swap OD A833 parts as a set into the correct case. All of the parts are the same in any o.d. or A8233 4spd.

Strength Considerations

Chrysler engineers decided that Hemis required a stronger input shaft so the standard 23-spline shaft was replaced with a larger 18-spline unit and a larger input bearing was used to accept the additional torque. Later Chrysler decided that the 440 6 pack cars also needed this larger input shaft as well. It is one of only a couple of things that set the Hemi four speeds apart from the standard 4.35" A-833s as being heavy duty. As far as strength is concerned, outside of the input shaft, the input bearing, the retainer and some special gear sets, there were no additional measures added to A-833s for the Hemis. The only other difference between a Hemi A-833 and a Slant Six A-833 were the gear ratios used. The Slant Six, small block, big block and o.d. 4-speeds are just as strong as the Hemi units.

The Overdrive A833s used a giant 5.125" bearing retainer and a large input bearing behind the retainer as sort of a reinforcement measure. Most manual transmissions spend most of their time in a 1 to 1 ratio top gear. When a non-Overdrive A-833 is in top gear (fourth), the input shaft is locked to the output shaft by a sliding collar. This locks the two shafts together creating a 1:1 output ratio, hence the term "direct drive". In fourth gear, the countershaft cluster gear in these transmissions is along for the ride and spins with no power load being applied. In an Overdrive four speed, since third gear is really the "direct drive" gear, and the o.d. gear is really where the old third gear used to be, the transmission spends most of its time with torque being applied through the countershaft and back to the output shaft, just like the lower gear reduction ratios. The Chrysler engineered solution for the added strain on the input bearing was to increase its diameter and the diameter of the bearing retainer hence the use of #308 type front bearing. Because of the final drive speed difference between the front input shaft and the main output shaft while the OD A833 is in long term highway cruising mode, the roller bearings between the two shafts do more work, and as a result, show more wear. It is important to inspect these rollers and their races for pitting whenever rebuilding an OD A833.

Shifters, Shift Rods, and Floor Humps

All Chrysler A-833s were equipped with Hurst shifters with the exception of the Inland shifters from 1966-1968. The Inland's are pretty recognizable. A nice feature of an Inland shifter is that it has a pull-up reverse lockout lever. There was a huge variety of OEM Hurst shifters built and Hurst has anything you need from shift rods to new shifters. They also have a rebuild service for your shifter.

It is important to point out that there is a shifter mounting plate or adapter which goes between the transmission's 3 bolt shifter mount and the 2 hole shifter box. There are many different adapter plates used for different chassis. The shifter adapter plate will angle the shifter lever and has an effect on shift rod lengths. There are many variations over the years and needless to say, you need the right one for your setup. Shifter linkage rod length changed between the different platforms (A, B/C, and E bodies) as the adapter plate / shifter was placed at different locations along the tailshaft. Additionally, the A and F-body Overdrive A-833s used a different 3rd-4th rod to accommodate the up-side-down shift operating lever. On top of all that, the hole in the lever that the linkage rods fit into changed in diameter at some point during the four speed shifter years.

Four speed cars require a special floorboard hump alongside the trans tunnel to clear the shift rods and the shifter. This is because the floor shift linkage runs over the top of the transmission mount cross member, basically through an area which is currently part of the passenger compartment of an automatic car. From the factory, these floor humps were stamped steel pieces that were welded to the regular floorboard after an appropriately sized hole was stamped out of a common floor pan. Any automatic to four speed conversion will require cutting a hole and adding a hump extension and adding to the frame of the chassis in question. The hump's size and shape varied from platform to platform as well as year to year in some cases. Depending on the year and platform of the car, you will either have to procure an original hump cut from a donor car or find a fiberglass or steel reproduction. .For the A-bodies, the OEM stampings changed at least four times as follows:

1964-65 round hole for shifter.

1966 hump is the same as 1964-65, except an oblong shifter hole is used. 1967-74 available as a fiberglass reproduction, as well as a new stamped steel piece.

1975-76 similar to the 1967-74 floor humps. These turn up on eBay almost weekly. Brewers also sells new and used pieces. At one time they were producing the hump for the early A-body. Year One and The Paddock are also good sources for the humps and 4 spd parts as well as Passon Performance.

Truck Overdrive and four speeds:

There were three types of four speeds installed in trucks in the late sixties and till the late eighties. One was the A-833 4 spd. standard transmission. Same unit used in passenger car. The overdrive four speed which is basically a passenger car A833 four speed was also used in trucks from the late '70's till the late '80's. The other four speed was the A-435 which is a huge truck four speed, it has a non-synchronized granny low first gear. The A-435 requires a huge cast iron bell housing and a 143 tooth flywheel. The cast iron bell housing was not used after the '60's in the trucks. Once you are familiar with identifying A-833s, there is no way you'd confuse the two transmissions. The A-435 is a top loader, where as the other A833 and o.d. A833 4spds have a side cover and shifter linkage.