How much abuse can the Ford 3.03 take?

I've got one from a '74 F100 sitting around, and I've thought about using it for something. But I'd hate to put it behind a big torque/high HP engine only to watch it fail right away. Does anyone have any numbers to their limits?

 

WTF is a 3.03?

 

bullet proof...

 

the 3 speed version of the Top Loader trans.

I think the 2 barrel 390 is the biggest motor they put it behind

 

I think you are right. And I forgot to mention mine was behind a 302cid, so I'm assuming it's the 1 1/16th input diameter.

 

That's why I love this place, learn something new everyday. I have a 3.03 (but didn't know what it was called), if anybody needs one.

 

I've heard that you can install a top shifter in these by using the top plate from the Jeep 3-speed. Havent done it myself.

 

Heard the same thing. May try it if I can't locate a Hurst Indy shifter.

 

http://www.davidkeetoploaders.com/imposters.htm

 

A friend bought a F-100 new in 1978 with one of these RUG overdrive transmissions behind a 300 six. He had to rebuild the thing two or three times in the years he owned it, they weren't very strong at all.

 

Back in the 60's GM didn't have a three speed trans that would take the HP of their Muscle Cars - Pontiac engineers tried everything and they tore up with less then 10 launches - Finally is desperation they tried the ford 3 speed 3.03 Toploader and it withstood anything the threw at it including the Catalina's with the 421 Super Duty - They made a deal with Ford and used them for a numbers of years until they designed one strong enough to hold the power.
Why were they so desperate for a 3 spd? - The insurance company's had declared that any car with a 4 spd manual trans was a high risk and they jacked up the rates.
There are all sorts of posts on the INTERNET about the "Good" 3.03 vs the "Bad" 3.03 - Look threw the parts catalog and it turns out that the only difference's that you can find are gear ratio related IE the number of teeth on the shafts and the gears
If anyone has any concrete info (Part Numbers) on the strong vs week please post the info.

 

Are you talking about the 4 speed, 4th OD? If so, yes those are JUNK.

The 3 speeds are pretty tough.

 

Here is a link to the Dearborn Three Speed Transmission manual that was used in Poncho's
You can see by the pictures that it is identical to the 3.03 Ford

http://thefirstgensite.com/library/68sm/3spddear/3spddear.html

 

I worked for Ford for 32 years the 3.o3 3 speed is almost bullet proof. A customer brought in a 65 Belair with a396 in it that had a 3.o3 colum shift in it. I remember put a clutch in it. He was an older man some kind of traviling salesman. I ask him about the trans and said thats the way the car was built.

 

Its a toploader minus one gear. They're about as strong as they come.

 

Local guy swapped a 3.03 into a 427 63 Galaxie R code to replace the destroyed factory T10. Seemed to hold up quite well.

The RUG problem was wear on the countershaft. I wore out 2 of them (countershafts) in my 6 cylinder 79 Ford Van.

 

We couldn't keep bearings in them on my 78 F150, my B-I-L's 79 F150, and a buddy's 150.

 

I have one in my 27 that has been in there for over 20 years. It came out of a 68 Galaxy with a 390 in it. I have a Hurst Sycroloc shifter on it and it has never missed one shift or given me any problems.

Originally the car had a 302 but a year ago I went to a 331 stroker Ford and wondered if the trans had reached it's limits. But I just ran it at the BP drags, with slicks and some hard launches, and the transmission just kept on ticking along. You won't ever hurt it with a 302.

Don

 

There is a 2.42 three speed manual that I recall (and I could be wrong) has a larger input and was used behind the biggest of FE's in heavy cars.

The ratios are 2.42/1.61/1.00.

EDIT: Apparently GM used them in GTO's as well.

 

What I have found is the listing for three input shafts that correspond to the three ratios listed here - All 3.03 transmissions that I have seen all have the 1 1/16 inch input shafts - I have found only one input shaft bearing retainer and it is for the 1 1/16 inch shaft - I have seen mentions of wider synchronizer units but no part numbers - I have seen mention of a smaller front blocker ring but no part number - I have seen mention of the longer RAT main case but no part numbers that will account for the differences - I have seen listings for three different output (Main) shafts lengths and the can be accounted for by the 4x4 version, the truck version and the car version
3.03 Toploader ratios
2.99 1.75 1.00 3.17
2.79 1.70 1.00 ?
2.42 1.61 1.00 2.33
GM used their own specs for the 3.03 and called it the Dearborn Transmission - The first of these were made by Ford and then by Borg/Warner - I have seen them, drove them, and raced one in a 6 cyl Altered - They were a tough as the Ford ones

I have a diagram of a generic transmission with measuring points for specific dimensions - If anyone would like to contribute to a data base please PM me and I will send you the diagram

 

Falcon George,..YES you can !!!! Bulletproof, behind a Henry Flatmotor. For 3 speed units, get a CJ5 shifter, remove the rails and forks,...plug the side shift holes in the case, and you're in business . You do have to plug one hole in the case front, where the rail went thru.

There are 2 variations of the 3 speed toploader,...One being the small spline (input) T150 and the other is a big (input) spline, known as the "RUG" unit. Both can be converted by using the CJ shifter.

4TTRUK

 

I wish I had some better pictures of the one in my 27 but this is all I have. Been running it for over 20 years without even having to put seals in it and it has taken some serious abuse.

Don

 

The T150 was an AMC/Jeep version of the 3.03 that was a toploader Top shift it is the unit that you mentioned that you get the topshifter from
The RUG Transmission is a four speed thansmission some of which are the weaker 3+1 OD units

 

I had one behind my hopped up A-code 289 and it survived alot of abuse.

 

Love 3.03's. They can take some serious abuse. Grew up on em and any time we could get our hands on one it was gettin used.

 

A friend in college (1974) had a '67 GTO with the 3.03 behind a 400. The trans had "fomoco" on the side.

We abused that car and it took everything we threw at it

 

My plans are to put the one I have behind a Ford 400 stroked to 434cid. Tim's dyno has these engines pushing 500+ hp and 500+ ft lbs at a pretty low rpm starting. I would anticipate with 3.73 gears that my Fairlane will get up and go plenty good even with only 3 gears. I thank everybody for confirming my thought that these are plenty stout.

Dick, I'll get those measurements as soon as I can..... sometime in the next month or so. We've been lucky that we haven't had hardly much snow, so I can still make my way down the trail to where it's sitting.

I've also heard these were used in "other" makes and models for awhile, too.

 

I had a couple that were close ratio with 1 3/8" inputs. They where from trucks, had the early narrow pattern. One had a short tailshaft, one long. They would have been in something like a '63 F100 with a 292.

This picture isn't one of mine, but that's what they looked like.

 

I bought a new Pontiac in '69 with a three speed. Trans had FoMoCo cast in to it. Kind of a surprise. I have used a top loader three speed in my Bonneville Vega behind a 460 (197 mph) and a 455 Pontiac (208 mph) and ity still works fine. I also have a fresh one with a Gear Vendors OD for sale.

 

My first car was a '56 Ford. I went through nine transmissions in 1-1/2 years. I put in a 3.03 and never tore out another.