03-25-2015, 10:59 AM | #1 |
Senior Member
|
Rear end swap
I have a 36 Fordoor with a 4:11 rear. What years can I do a straight swap to a 3.78 without modifications? I'm thinking 36-40?? Can I swap out just a center section? Thanks guys.
__________________
Tim Carlig |
03-25-2015, 01:25 PM | #2 |
Senior Member
Join Date: Sep 2011
Location: Muskegon, MI
Posts: 252
|
Re: Rear end swap
look here; http://www.flatheadv8.org/fordrear.htm
|
Sponsored Links (Register now to hide all advertisements) |
|
03-25-2015, 01:31 PM | #3 | |
Senior Member
Join Date: May 2010
Location: Southern California
Posts: 7,031
|
Re: Rear end swap
Quote:
Charlie Stephens |
|
03-25-2015, 01:41 PM | #4 |
Senior Member
|
Re: Rear end swap
Charlie, can't I swap out a center section and make necessary adjustments with the shims? Looks like spring perches are different 36-40....will the 36 spring still fit?
__________________
Tim Carlig |
03-25-2015, 01:46 PM | #5 | |
Senior Member
Join Date: May 2010
Location: Southern California
Posts: 7,031
|
Re: Rear end swap
Quote:
Charlie Stephens |
|
03-25-2015, 01:51 PM | #6 |
Senior Member
|
Re: Rear end swap
Sponsored Links (Register now to hide all advertisements)
__________________
Tim Carlig |
03-25-2015, 02:36 PM | #7 |
Senior Member
Join Date: Jul 2011
Location: SF Bay Area
Posts: 6,641
|
Re: Rear end swap
Tim, The center section of any early Ford differential having the gear ratio you want will swap in without modification. You will need a 6/10 driveshaft coupling, and a set of banjo gaskets. Likely you will need a set of shackles also. I suggest teflon shackles from Speedway. I also suggest that you get two sets of gaskets. Split one set for a quick determination of correct shims per side to avoid complete disassembly/reassembly for each trial fit. Never rethread the banjo threads and bolts, as they are meant to thread tightly to prevent leaks. On final assembly, use thread seal on those banjo bolts.
__________________
Alan |
03-25-2015, 03:52 PM | #8 | |
Senior Member
Join Date: May 2010
Location: Near Rising Sun, Maryland
Posts: 10,858
|
Re: Rear end swap
Quote:
If you just want to swap your existing 4.11 ring and pinion gear set, that more than likely has a 10 spline pinion now, without making other modifications, you would need to find a 3.78 matched ring and pinion gear set that also has a 10 spline pinion. This requires going through all the bearing preload steps and setting the mesh of the ring and pinion gears by placing the correct number and thicknes of gaskets/shims between axle housings and center banjo housing. There is no quick and easy way of doing this correctly that I know of. All of this assembly must be done by the correct procedures or its not going to work.
__________________
John "Never give up on what you really want to do. The person with big dreams is more powerful than one with all the facts". Albert Einstein Last edited by JM 35 Sedan; 04-14-2015 at 02:23 PM. |
|
03-25-2015, 04:19 PM | #9 |
Senior Member
|
Re: Rear end swap
Thanks for all the info guys, now I can make an offer for one I found.
__________________
Tim Carlig |
03-25-2015, 04:24 PM | #10 |
Senior Member
Join Date: May 2010
Location: Powell, TN
Posts: 2,509
|
Re: Rear end swap
I think you will find that a used gear set will need no additional gaskets. I have put several together with just silicone to seal them. Over the years they easily wear so if anything they need tightning up. Put the side with the ring gear on first and see if there is any resistance, if so then add gaskets.
|
03-25-2015, 06:21 PM | #11 |
Senior Member
Join Date: Jul 2011
Location: SF Bay Area
Posts: 6,641
|
Re: Rear end swap
You guys...! I don't understand your confusion! All he wants to do is swap out a center section. He'll be using all his '36 parts but the center section, and will need a 6/10 drive shaft coupling, period. No other fuss.
Maybe I'm the one behind that 8 ball? I don't see the problem you guys see?
__________________
Alan |
03-25-2015, 06:54 PM | #12 |
Senior Member
Join Date: May 2010
Location: East Shore of LAKE HOUSTON
Posts: 11,108
|
Re: Rear end swap
Gotta be careful about axle tooth count/spiders. DD
|
03-25-2015, 07:48 PM | #13 | |
Senior Member
Join Date: May 2010
Location: Near Rising Sun, Maryland
Posts: 10,858
|
Re: Rear end swap
Quote:
Also, his question about swapping out just the center section was his second question. Go back and reread his first post to understand his first question.
__________________
John "Never give up on what you really want to do. The person with big dreams is more powerful than one with all the facts". Albert Einstein Last edited by JM 35 Sedan; 03-25-2015 at 08:09 PM. |
|
03-25-2015, 09:16 PM | #14 |
Senior Member
Join Date: Jul 2011
Location: SF Bay Area
Posts: 6,641
|
Re: Rear end swap
John, I've never actually seen a 6/10, so I assumed it would work either way by flipping ends. It didn't even occur to me that the hollow shaft has a female spline....So, I sure am behind the 8 ball on that one!
On his question, I just understood that he meant center section from the git go. Sometimes these long distance conversations get twisted between sender and receiver, don't they? And to Coopman, assumption on my part was that he was aware of tooth count on the spiders, or at least would have discovered the difference all in good time!
__________________
Alan |
03-25-2015, 09:48 PM | #15 |
Senior Member
Join Date: Oct 2011
Location: Shelton, WA
Posts: 3,800
|
Re: Rear end swap
I didn't see anywhere the mention of the spiders. The axle ends have different number of teeth but are the same length. If you use the 40 axles, no problem, if you are going to use the 36 axles, you need to change the spider gears.
|
03-26-2015, 07:47 AM | #16 |
Senior Member
Join Date: May 2010
Location: Powell, TN
Posts: 2,509
|
Re: Rear end swap
YOu can use the 40 drive shaft and torque tube. If necessary, relocate the boss that radius arms bolt to. 35-40 TT and DS are same length.
|
03-26-2015, 08:34 AM | #17 |
Senior Member
Join Date: Jul 2010
Posts: 2,593
|
Re: Rear end swap
We also have to pay mind to the carrier bearings don't we? Just asked a question about these on the modern bearing thread. Was informed that the carrier bearings need to match the axle casings. So if you use a 40 center section with 35 axle casings, you need to swap on the 35 carrier bearings.
Unless I got it all fuddled up. Martin. |
03-26-2015, 06:37 PM | #18 |
Senior Member
|
Re: Rear end swap
Ok Guys, I found a complete assy less backing plates from a 37 pickup, am I good to go?
__________________
Tim Carlig |
03-26-2015, 08:32 PM | #19 |
Senior Member
Join Date: May 2010
Location: East Shore of LAKE HOUSTON
Posts: 11,108
|
Re: Rear end swap
If it has the spring, torque tube and bones attached, it should glue right in place. Only thing to consider is the brake rod routing for the '36, as the '37 used cables.
If you have hydraulics, you're golden. DD |
03-27-2015, 03:10 AM | #20 |
Member Emeritus
Join Date: May 2010
Location: Fitzgerald, Georgia
Posts: 2,204
|
Re: Rear end swap
I REALLY doubt the 37 pickup rearend has 3:78 gears. Better do some checking before installing a 4:11 in place of a 4:11.
|
|
|
Sponsored Links (Register now to hide all advertisements) |
|