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I'm building a truck out of 3 and I'm trying to decide which transmission to use. 2 of my donors have 4 speed manuals and the other is shown on the shifter as a 3 speed manual with an over drive. Is one better then the other? 82 and 84 have the 4 speeds and an 83 has the 3 speed with overdrive.
The 4 speeds are probably the T18 style “Granny” 1st gear type transmissions. Basically a 3 speed with a compound low first gear. Never was a fan myself but they are strong/heavy. The 3 speed overdrive if original could be either the SROD or TOD depending on the shifter location.
The Single Rail Overdrive has the shifter mounted toward the rear and the TOD has it mounted on top like the 4 speeds.
Although weaker and lighter I much prefer the 3 speed overdrive unless it’s a work truck that will be hauling/towing a lot. Parts are sometimes harder to find for them, make sure the shifter assembly is in good shape. They get a bad rap cause people use them to haul and tow in overdrive and burn the small overdrive gear up.
In case it’s been swapped There’s also the 78-79 T170 style 3 speed overdrive that is side shifted via rods like an old Toploader car trans. Similar gearing as SROD. I have an original one in a 78 and happen to like it other than the large rpm drop from 2nd to 3rd.
Just depends on what you’ll be doing with your truck but for general daily driving street cruising the 3 speed overdrive hands down. You’ll like extra gas mileage too.
Everyone on here will tell you to put a five speed in but nothing wrong with using what you have there if they’re in good shape.
My '85 E150 had the iron cased, side shifted 4 speed OD.
I know Ford and everyone else calls these 3 speed with OD but just a few model years earlier that would be a Borg Warner 3 on the tree with a separate OD.
All the 4 speed OD were patterned on the performance top loader transmission. The top shifter is popular with hot rodders and was also available in Jeeps.
Chrysler did the same thing with their performance 4 speed the A-833. Also known as the NP440, GM also used it in pickups and I'm not sure what else.
The 2nd to 3rd gap is worse with taller gearing. I had 3.50s and 31-10.50s and it was intolerable on back country hilly roads. With the stock tires it was "just" OK.
Back to the OP--you are building trucks--for what? Truck stuff use the granny gear box. Mild cruise, the OD.
Performance? Sell all of them and get a beefed up automatic. None of the transmissions in question is a good performance transmission--slow shifting, overwide gearing, and strength, all or one in each box.
A quote from a Numberdummy post. I thought the 3 speed with the OD were offered later. '71 was the last year. Passenger Cars (1949/67) and F100's (1953/71) were available with a Borg-Warner 3 speed manual with Overdrive w/a column mounted gear shift lever. These trannies have a non synchro 1st gear.
I believe
If the trans is an OD it is a car trans based on the Toploader (in a round about way)
Those T18's and 19's shift slow but are strong truck transmissions
A quote from a Numberdummy post. I thought the 3 speed with the OD were offered later. '71 was the last year. Passenger Cars (1949/67) and F100's (1953/71) were available with a Borg-Warner 3 speed manual with Overdrive w/a column mounted gear shift lever. These trannies have a non synchro 1st gear.
Never seen or heard of a Ford car or truck with a column mounted 4 speed shifter. And a 3 speed transmission with a overdrive gear is ridiculous just thinking about it. How in the world would you get from a take off gear ratio to a overdrive ratio with only 3 speeds?
i have heard of little foreign trucks with a 4 speed column shift. Very difficult to get reverse on those.
The transmissions in question from the OP are the floor shifted 4 speed OD models. "Everyone" calls them 3 speed + OD but they're not......
The early 80’s SROD and the 78-79 T170 Toploader style are exactly a 3 speed + overdrive even though they have 4 forward gear positions (speeds). Third gear is 1 to 1 and High gear is around .78 to 1 which is considered overdrive because it’s a higher ratio than 1 to 1. Same concept as any other overdrive such as ZF5 and M5OD for example where high gear is higher (numerically lower) than 1 to 1.
No, the ZF5 and M5OD examples aren’t referred to as 4 speed + overdrive but that is exactly what they are.
As said we need to know what you are building the truck for, pulling heavy loads or just driving around?
Would this be the 82 F250 with the 4.9 or something else?
My 81 F100 with a 4.9 / 300 I built as a back up to pull my open deck 20' car trailer and wanted the granny first transmission.
Truck started with a T18 from the factory but found it was bad when I got the truck on the road.
My replacement is a NP435 also with a granny first and at the same time added Advance Adapter over drive and can split each gear.
Yes the granny first transmissions shift slow but they are a TRUCK transmission.
I dont have any issues with the way the transmission shifts and I drive it in town mostly.
If I wanted a race truck it would not have a straight six for a motor!
Dave ----
As a side gig/hobby I’ve been rebuilding these old 3,4,& 5 speed transmissions for the past 15 years or so, got them laying all over my shop. A lot of people either don’t remember or have a clue what the early 3 speed overdrive with solenoid is including many folks I’ve bought truck loads of cores from. The only one I’ve had the pleasure of working on was on a GM Saginaw trans.
People, rightly so, call the SROD and T170 a “3 speed overdrive” to differentiate it between the old 3 speeds and 4 speeds that were available or previously available at the time, just like Dave Kee does on his website that 85e150 linked.
Nowadays the 5 speed (and 6 speed) moniker is used mostly to simply differentiate from an automatic transmission whether overdrive or not. The majority of people could care less if their 5 speed is overdrive unlike the late 70’s early 80’s when overdrive (without a solenoid) was still something relatively new.
But Back on topic, to the OP, do you know what rear gears you have? My ‘78 with the 302 3 speed overdrive came with 2.75 gears and needless to say it was a real turd especially in hilly country. This also puts a lot of stress on the transmission especially the tiny overdrive gear!
I installed 3.70 gears and it does a good job with the 28” tires on it. Turns around 2300 rpm at 65 mph in overdrive. Down shift to 3rd (direct) for longer hills. Granted it’s not the performance trans that a true Toploader is due to the very wide gear splits, but it shifts smooth without the “clunkiness” of a granny truck trans and does fine in my stockish 78. It’s also correct original for the truck which is important to me. The 3.70 gears help pull through the 2-3 rpm drop. And contrary to what some believe the 3.25 first gear isn’t affected as bad as it would seem. My old F100’s are high end builds/restorations that are cruised around like cars, not race cars or work trucks.
On the other hand I know a fellow who has a T18 “granny low” behind a 302 in a F100 with 2.75 gears and loves it. Again It’s a street cruiser, not a race truck or work truck. To each his own.
After looking at castings it appears as though I have a run of the mill T18 with an incorrect **** screwed onto the smart end of the stick. So a T18 it is for the project
