A833 transmission for my flathead

[Merle Coggins]

9 hours ago, nkeiser said:

... Magically, my stock speedometer is only 5 mph off after that odd combination....

 

Makes you wonder how far off speedos were back in the day. I swapped the diff in my truck with a 3.73 diff from a '50 Plymouth. Still running the stock 4 speed trans, and my speedo is only a few MPH off. Since they didn't have GPS, and cops with radar,  to confirm the accuracy back then I suppose they didn't care. 

[Tony_Urwin]

nkeiser, If you have a 3.09 from an 80's pickup, I'm assuming that must be the overdrive A833:

1. 3.09
2. 1.67
3. 1.00
4. .73 (overdrive)

How do you like the shift points on the overdrive transmission? Do you find yourself winding it up in first and then dropping a lot of RPMs for 2nd gear?

[nkeiser]

On 11/5/2024 at 10:04 AM, Tony_Urwin said:

nkeiser, If you have a 3.09 from an 80's pickup, I'm assuming that must be the overdrive A833:

1. 3.09
2. 1.67
3. 1.00
4. .73 (overdrive)

How do you like the shift points on the overdrive transmission? Do you find yourself winding it up in first and then dropping a lot of RPMs for 2nd gear?

Honestly, I really haven't paid attention or noticed any issues. Drivability was pretty rough initially when I had idle set around 500. Bumping that up to around 1000 really helped drivability. The issues were mainly around starts, but the higher idle likely helped between shifts as well. 

[Merle Coggins]

8 hours ago, nkeiser said:

Honestly, I really haven't paid attention or noticed any issues. Drivability was pretty rough initially when I had idle set around 500. Bumping that up to around 1000 really helped drivability. The issues were mainly around starts, but the higher idle likely helped between shifts as well. 

 

If you need the idle speed to be that high for good drivability then you likely have something wrong somewhere. Either your carburetor is not properly adjusted to be too lean, or to fat, or your ignition timing is off. It could also be that your points aren't providing the proper dwell time for good coil performance, which causes weak spark and sometimes maladjusted ignition timing. Another possibility is that you have a vacuum leak somewhere. This will also cause an over lean condition at idle which makes the engine not want to perform correctly at idle. 

[nkeiser]

On 11/7/2024 at 6:53 AM, Merle Coggins said:

 

If you need the idle speed to be that high for good drivability then you likely have something wrong somewhere. Either your carburetor is not properly adjusted to be too lean, or to fat, or your ignition timing is off. It could also be that your points aren't providing the proper dwell time for good coil performance, which causes weak spark and sometimes maladjusted ignition timing. Another possibility is that you have a vacuum leak somewhere. This will also cause an over lean condition at idle which makes the engine not want to perform correctly at idle. 

Good point. I actually had to raise the idle a few years ago due to a carb tuning issue. I got that resolved (combination of junk stuck in the seat causing flooding and idle mixture) and never readjusted down. It runs great, but the higher idle helps starting from stops. I haven't messed with tuning much the past few years since I started a new project car. I'm avoiding wiring issues on that one, so I may tinker on the Dodge this weekend.

 

I have dual Webers from Langdon and electronic ignition. I had it purring great then ran into an issue at the Salina show a few years ago. After fixing it in the hotel parking lot, I haven't messed with it--just start it and drive.

[Sniper]

Rear mounted shifter means e-body. To the best of my knowledge there are no different length input shaft. They are all the same length. As for your gear ratio concerns before you spend any money just put in what you got test driving to see if you like it or not if you don't then you can think about a gear swap.

[9 foot box]

   I suggested that a week ago. Our car first gear ratio is 2.57, higher than a truck three speed gearing. 2.47 is high but I think the torque of a flathead engine would offset that. Nothings going to happen for awhile, if Tony got his scheduled new hip today. Classic car database.com.

[Tony_Urwin]

Deleted incomplete post.

 

Edited November 13 by Tony_Urwin

[Tony_Urwin]

I really appreciate the feedback from everyone. As 9 foot box mentioned, I had a hip replacement done yesterday morning, came home in the afternoon. It went extremely well, the anesthesiologist did a great job. He did a nerve block in my hip using ultrasound, and as a result he could use less fentanyl and propofol. I woke clear-headed which has never been the case with previous surgeries.  I even made a trip to the bathroom at 1:30am with no assistance, no crutches, nada. Pretty amazing.

Back to trucks. I had a busy week beforehand, getting things in order at work, end of season yard work, etc, so I had little time for the truck. I have read over the comments and want to make some replies, especially to anyone interested in possibly doing the swap themselves.

                                          

If you are considering an A833, do your research. There are a bewildering number of differences in the A833 models (1964-1987). For the purpose of this post, all my comments refer to A833 with 23-spline input shafts, used for the Aok Boys adapter plate.

First: Tail housings and shifters, very important to consider. 

• Sniper mentioned rear-mount shifters as E body cars (correct) Some tail housings have dual mounting points for the shifter, like mine which also has a forward mount (B body). There were also other tail housing in different lengths and different shifter mounts (A body, B body, E body, F body). Some have a single mounting point, some have two. Some even have one set undrilled.  The 1964-65 A833s used a less desirable trunnion-style output (along with an A body shifter mount), later units used a slip yoke output. Look for a tail housing with the forward (B body) shift mount or your shift handle will want to come up through the middle of the bench seat.
• Most of these A833 models used a Hurst shifter.  Those Hurst shifters have three plates which control the shift linkages. The plates and linkages are also different for different tail housings and vehicles.  The shifter plates and linkages are interchangeable. Mopar also used a less desirable Inland shifter (‘66-mid ‘68)with a shift lever that can be pulled out of the shifter.

Next: Gear sets, Input Bearing Retainers, and Throw out Bearings.  

• Gear sets. 9 Foot Bed posted the list of gear sets (See Above). Most common for the AoK adapter would be the A833 Overdrive, which has 3.09 first gear and a 5.125” Input Bearing Retainer. My transmission has the 2.47 first gear, often are referred to as a close-ratio A833. I like the close ratio non-Overdrive gear splits and I have a 3.55 rear axle from a Jeep Cherokee, so I don’t really need the overdrive.  Some here have suggested that my 2.47 first gear will be too high behind my 230 truck engine. (2.47 X 3.55 = 8.77.)
• The most common first gear in the non-Overdrive units is 2.66.  Just know what you are getting, and how will work with your rear axle. I have found that most of the sellers don’t know the gear ratio of their transmissions. I had to wrap my input shaft with masking tape, and then mark it as I turned the slip yoke after I shifted the gears.
• I haven’t approached throw out bearing situation yet. A throw out bearing came with my A833, but I don’t know if there I a chance it will work with my clutch fork and clutch assembly.

It will probably be Spring before I attempt to install the transmission, but I have other things to do on the truck (paint, interior, power windows, etc.) so after a few weeks of physical therapy I’ll be back at it.

 

Most of my information here came from Jamie Passon's book, Chrysler A833 Transmissions, the factory Service manual, or discussions with Dan Brewer. I have found lots of questionable info on the internet. Hit me up with any questions, tips, disagreements, etc. I’d love to hear what you think. I may even decide to sell the A833 I bought, especially if I find a rare one-year-only 1975 non-Overdrive A833 with the 3.09 first gear😊

Edited November 13 by Tony_Urwin

[Sniper]

The early ball and trunnion A833 also came in the long variety, for B and C bodies.  Had one in my 64 300.

 

There are basically two lengths of A833.

 

Short, for A, F, M body cars.  F and M only ever had the OD variety.  Some A body versions used the smaller (A904 style) slip yoke.  Most used the larger (A727) style slip yoke.

 

Long, for B.C and trucks,  later ones had the dual shifter mount set, truck ones were all OD variety.  All used the larger slip yoke.

 

There were a couple of flavors of gears sets, but that's been covered.

 

I have two A833OD's out of trucks on the shelf.  Thinking about putting one in my 51, but maybe not with the adapter mentioned.

 

 

 

 

 

 

[Tony_Urwin]

 Sniper, you're right about the longer ball & trunnion types. Jamie Passon's book says there were 3 different tail housings in 1964-1965. The A-body had the 3.09/1.92/1.40/1.00 that I like, but I believe it only came with the shifter positioned farther back than B-body cars. B-body cars had better tail housing, but a 2.66 first gear.

 

I'd love to see your A833 in a 51 swap.  I saw a YouTube video where they put an OD unit in a '50 Plymouth.

[kencombs]

My A833OD came from a van.   Long tail shaft, two shifter locations, Hurst shifter and a weird mount that placed it forward, upward and angled down.   To fit the van's seat/engine configuration.   Using the shifter, will make new mount and shift rods, someday, when I put the whole thing together.   Right now the engine/trans is sitting beside the frame/cab waiting for the firewall to get painted.  My painter (ME) is busy with other things that are higher priority.   Tornado damaged roof replacement etc.

[Tony_Urwin]

Thanks, Ken (and Los Control) for the suggestions about the countersink bit. Something I could get done while I wait for my hip to get stronger. Did you post any pictures of your transmission/shifter mount? Everyone loves pictures.

 

I probably covered this already, but I took my E-body Hurst shifter and linkage to Dan Brewer, since I wanted to change shifter location. He changed one of the plates in the shifter and swapped my linkage for the shorter ones I needed to use the B body mount. He also gave all new clips for the linkages.  All for $56 if I remember correctly.  BrewersPerformance.com  Good resource if you need parts for your eventual tranny swap.