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JH rear end information...  Rating:  Rating
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 Posted: 06-25-2006 12:08 am
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Frank Schwartz
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Can anyone tell me if the rear transmission on the JH is the same for every year.
Reason: My daughter has a 74 with transmission (4sp) that needs rebuilding.  I am  hoping to purchase a 76 (5 sp) that is for parting out, and would want to swap the transmissions over.  And is the drive shaft the same for both?
To be more succint..do all JHs 73-76 have the same rear end...and do all, both 4 speed and 5 speed, use the same drive shaft??
Thanks...

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 Posted: 06-25-2006 08:36 pm
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Scott Robinson
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Hi Frank.

Since no one else has replied...

The 4-spd and 5-spd rear ends are slightly different. The 5-spd rear end has a slightly higher (lower numerically) ratio and the pinion flange is different from the 4-spd. The 5-spds came with 2-piece drive shafts with a center coupling/support. (Sherman just replaced his with a 1-piece Delta sells.)

My wife and I are visiting Nashville and Franklin next weekend. Isn't that your neighborhood? Any tips on must sees around Franklin besides the Carnton Plantation?

Scott

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 Posted: 06-26-2006 01:06 pm
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Mitch Ware
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During the convention there a couple of years ago, Frank aranged for us all to go to the Lane Motor Museum, it is a must see imho. http://www.lanemotormuseum.org/

Mitch Ware

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 Posted: 06-28-2006 04:31 am
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Frank Schwartz
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Consider the Hermitage...well worth the visit...
ABOUT THE HERMITAGE
 
The Hermitage, Home of President Andrew Jackson, is one of the largest and most widely visited presidential homes in the United States. The State of Tennessee purchased the property from the Jackson family in 1855-56. Since 1889 the Ladies’ Hermitage Association has cared for the property as a historic site museum. Today The Hermitage is a 1,120-acre National Historic Landmark. Thanks to the Association’s efforts, almost all of the mansion’s contents are original. The Hermitage is a national model for authenticity, conservation, and preservation. The Hermitage mansion recently underwent an award-winning, extensive $2.5 million interior restoration, making this dwelling the most accurately preserved early presidential home in the country. In the past couple of decades, new initiatives and preservation programs have enhanced the visitor’s experience at The Hermitage--in such areas as archaeology, gardens and grounds, education, and the history of slavery. The Hermitage is Nashville’s first Smithsonian Institution Affiliate Museum. The site draws nearly 200,000 visitors annually, including 30,000 schoolchildren. The property also receives another 30,000 annual visits from the local community for a variety of recreational purposes, including over 1,000 children who play Little League baseball at The Hermitage's Rotary Park.

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 Posted: 06-28-2006 04:32 am
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Frank Schwartz
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or...call me for help or information....824-5467

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 Posted: 06-28-2006 04:45 pm
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Ron Earp
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Scott basically has it right from what I can tell.

The 4 speed rear ratio is like a 3.75, and the 5 speed rear ratio is like a 3.45 (numbers not exact).

The five speed will go right on the motor with no issues.  It will also go in the mount with no issues, but I re-designed mine to work with a stout common Chevy mount.

The drive shaft will be the issue, if you don't have one.  As Scott mentioned, the flanges are different on the differential, and, the yokes for the transmissions are different too if I remember right.

I got lucky and the 5 speed I bought came with a shaft that went to a 4 speed rear end, which was perfect.

If you are getting a five speed transmission and drive shaft you've got a couple of options:

*swap the five speed rear in too and use it all
*have the five speed shaft modified to bolt to the four speed (which would be easy to do).

All you'd need to do is carry the 5 speed drive shaft to a driveshaft balancing/repair place and they could weld a proper flange on the end of it for you.  Carry a pencil rubbing of the 4 speed differential input flange with you.

I have a four speed too, that is working fine, if you want that. Gladly trade it, some money, and labor to get another five speed for racing.

Ron

Last edited on 06-28-2006 04:52 pm by Ron Earp

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 Posted: 07-21-2006 04:26 am
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pbahr
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Frank,

All the responses are quite correct.

My opinion is that you should install both the 5spd Tranny and Rear.  You'll get lower rpms at highway driving by about 8%.  Replace the two piece Driveshaft with a one piece unit - buy from Delta, Pete's Kits (http://jhppg.com/pk1204.htm), or have a local shop make one for you (just be certain what you are buying).  A one-piece shaft will get rid of the troublesome center support as well.

When you make this conversion, you will have to move the rear Tranny mounting plate either forward or rearward (I don't recall which).  You will also have to drill a hole in the Tunnel to accept the upper mounting bushing.

Be aware, the Shifter mechanism on the 5spd is a troublesome device.  Check very carefully before you buy.  Many are worn in the linkage, and will give you a very unsatisfactory shifting experience - see: http://jhppg.com/pk0604.htm.

I'm not trying to sell stuff here, I'm only trying to help............   The links above will give you lots of technical details.

Pete

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 Posted: 07-22-2006 06:21 pm
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Jon Plowe
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Don't forget you'll need a  5sp speedo cable as well. You have to shift the mounting plate backwards

Jon

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 Posted: 07-22-2006 07:39 pm
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pbahr
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Jon,

Exactly correct - Speedo cable needed.  I did mine two years ago, and didn't look up the details.

Pete

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