The Ford Barn

39flyer · 12-06-2020, 02:49 PM

I’m changing my 39, 3.78 ratio rear end to a 3.54. I purchased a new 3.54 gear set from a Barn member. While installing new bearings I find the pinion shaft has a smaller diameter than the 3.78 shaft. In doing a little research l see there two different part numbers for the 3.54. Looks like one 3.54 is for a hollow driveshaft used on the 32 to 34. Both are six spline shafts.
Question is can I make the one I have work by getting the correct bearings and using it on a solid driveshaft?

deuce lover · 12-06-2020, 02:56 PM

Something strange there as late '32 -36 are 10 spline .Pinion bearings changed in '35 and pinion is also a bit longer.

bobH · 12-06-2020, 04:03 PM

Like Sheldon posted... There should be only three possibilities (for car/pickup). The L32-34, 10 spline, slightly smaller pinion bearing shaft and slightly shorter (9/16) pinion shaft. Next, 35-up to somewhere in the 38 era, 10 spline, slightly larger pinion bearing shaft and 9/16 longer pinion shaft (compared to L32-34). And, third, same as second except 6 spline. As for driveshafts... yes, L32-34 are hollow, 10 spline. And, 35, 36, and SOME 37, 38 driveshafts are hollow. And, the ones I've seen (few) are 10 spline. Beginning with SOME in 37 & 38, and up, the driveshafts are 6 spline and solid. What Sheldon posted, something strange. It seems like your post does not jive with the possibilities. There is one more possibility that I can think of (and I have done this). Take a 35-up pinion, and modify it to fit a L32-34 rear end. So, you get a pinion that had a shaft for the later bearings, turn it down to fit L32-34 bearings, and also trim off the tips of the pinion gears to fit the L32-34 banjo housing. This modification could be for either 10 or 6 spline.
For your case, I don't know of any way... I'm not aware of bearings that fit the smaller pinion, and also fit the later banjo that accomodates the solid driveshaft. And if you are working with a solid driveshaft, that implies 37-38 era-up, and 6 spline.
Caveat... I see in a catalog that current REPLACEMENT gears are offered with MORE possibilities. This suggests that I can't begin to make a guess as to what you actually have. I see in a Mac's catalog that they offered 3.54, 6 spline, to fit L32-34. This might explain your comment regarding smaller pinion shaft. IF (big IF) this is what you have, and IF they didn't shorten the pinion shaft for L32-34, then you could possibly make it work. I'm assuming L32-34 pinion bearings, and possibly a custom-machined sleeve to make the OD of the bearing compatible. I'm only babbling and speculating here.

Ronnieroadster · 12-06-2020, 07:06 PM

Quote:

Originally Posted by 39flyer

I’m changing my 39, 3.78 ratio rear end to a 3.54. I purchased a new 3.54 gear set from a Barn member. While installing new bearings I find the pinion shaft has a smaller diameter than the 3.78 shaft. In doing a little research l see there two different part numbers for the 3.54. Looks like one 3.54 is for a hollow driveshaft used on the 32 to 34. Both are six spline shafts.
Question is can I make the one I have work by getting the correct bearings and using it on a solid driveshaft?

If the bearing diameter area your referring to is where the two Timkin tapered roller bearings and twin bearing race is located there is another reason why that location is smaller. Halibrand six spline quickchange housings used modified Ford pinions the area where the Timkin bearings are located on a Ford pinion are reduced in diameter for the Halibrand the diameter I believe its .100 smaller. In original Halibrands the two pinion support bearings are ball bearings not the stock type Ford tapered bearings.
The 354 ratio is available for the Halibrand application sounds like you may have that set. I know this because I have Halibrands in everyone of my cars {5 so far} plus I build them for others.

Ronnieroadster

jetmek · 12-07-2020, 09:45 AM

Those are for the earlier 33-35? Rear ends. Instead of tooling up for a different gear set the suppliers simply grind the bearing seating area on the late style gears for the smsller bearings. AFAIK there are no bearings that will retro fit those for later rears

39flyer · 12-07-2020, 10:12 AM

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Thanks, guys, for the info. I have found out that this is a special gear set cut down for the 33-34 rear ends so won’t work in mine.

12-06-2020, 02:49 PM	#1
39flyer Senior Member Join Date: Aug 2014 Location: Oshkosh, WI Posts: 107	3.54 ratio change I’m changing my 39, 3.78 ratio rear end to a 3.54. I purchased a new 3.54 gear set from a Barn member. While installing new bearings I find the pinion shaft has a smaller diameter than the 3.78 shaft. In doing a little research l see there two different part numbers for the 3.54. Looks like one 3.54 is for a hollow driveshaft used on the 32 to 34. Both are six spline shafts. Question is can I make the one I have work by getting the correct bearings and using it on a solid driveshaft?

12-06-2020, 02:56 PM	#2
deuce lover Senior Member Join Date: May 2010 Location: Southern France Posts: 5,301	Re: 3.54 ratio change Something strange there as late '32 -36 are 10 spline .Pinion bearings changed in '35 and pinion is also a bit longer.

12-06-2020, 04:03 PM	#3
bobH Senior Member Join Date: May 2010 Location: so cal, placerville, vegas Posts: 1,394	Re: 3.54 ratio change Like Sheldon posted... There should be only three possibilities (for car/pickup). The L32-34, 10 spline, slightly smaller pinion bearing shaft and slightly shorter (9/16) pinion shaft. Next, 35-up to somewhere in the 38 era, 10 spline, slightly larger pinion bearing shaft and 9/16 longer pinion shaft (compared to L32-34). And, third, same as second except 6 spline. As for driveshafts... yes, L32-34 are hollow, 10 spline. And, 35, 36, and SOME 37, 38 driveshafts are hollow. And, the ones I've seen (few) are 10 spline. Beginning with SOME in 37 & 38, and up, the driveshafts are 6 spline and solid. What Sheldon posted, something strange. It seems like your post does not jive with the possibilities. There is one more possibility that I can think of (and I have done this). Take a 35-up pinion, and modify it to fit a L32-34 rear end. So, you get a pinion that had a shaft for the later bearings, turn it down to fit L32-34 bearings, and also trim off the tips of the pinion gears to fit the L32-34 banjo housing. This modification could be for either 10 or 6 spline. For your case, I don't know of any way... I'm not aware of bearings that fit the smaller pinion, and also fit the later banjo that accomodates the solid driveshaft. And if you are working with a solid driveshaft, that implies 37-38 era-up, and 6 spline. Caveat... I see in a catalog that current REPLACEMENT gears are offered with MORE possibilities. This suggests that I can't begin to make a guess as to what you actually have. I see in a Mac's catalog that they offered 3.54, 6 spline, to fit L32-34. This might explain your comment regarding smaller pinion shaft. IF (big IF) this is what you have, and IF they didn't shorten the pinion shaft for L32-34, then you could possibly make it work. I'm assuming L32-34 pinion bearings, and possibly a custom-machined sleeve to make the OD of the bearing compatible. I'm only babbling and speculating here.

12-07-2020, 09:45 AM	#5
jetmek Senior Member Join Date: May 2010 Location: albany Posts: 465	Re: 3.54 ratio change Those are for the earlier 33-35? Rear ends. Instead of tooling up for a different gear set the suppliers simply grind the bearing seating area on the late style gears for the smsller bearings. AFAIK there are no bearings that will retro fit those for later rears __________________ engine and component overhauls my specialty! Website- www.godevilgarage.com

12-07-2020, 10:12 AM	#6
39flyer Senior Member Join Date: Aug 2014 Location: Oshkosh, WI Posts: 107	Re: 3.54 ratio change Sponsored Links (Register now to hide all advertisements) Thanks, guys, for the info. I have found out that this is a special gear set cut down for the 33-34 rear ends so won’t work in mine.