My custom 32RH crossmember for the Savvy skid - JeepForum.com
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Unread 08-25-2013, 05:52 AM   #1
Sahara Surfer
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My custom 32RH crossmember for the Savvy skid

I really like the Savvy skid plate setup. Unfortunately, the good folks at Savvy don’t make a crossmember that fits the 32RH three-speed auto transmission in my 99 TJ (Not yet).

So… with some basic engineering and fabrication skills on hand, I set out to build my own custom crossmember for the Savvy skid. The design is based around AEV’s vibration isolation kit, which AEV was nice enough to sell it to me by itself along with all of their tummy tucker hardware. I mounted this on a piece of 1/4" plate.



Before I could size the support cross section, I needed to find out how much transmission dead load the crossmember would be supporting. I went about this by getting creative with a large bathroom scale.



The scale reads 225 lbs, but this includes the weight of the support blocks. However this does not include the additional weight of the removed drive shafts. As a conservative measure, I go ahead and design for 250 lbs.



On the AEV tummy tucker, the bottom of the low profile isolation pads are about an inch below the frame rails without the use of a body lift. I figured I can locate the isolation pads level with the bottom of the rails with a 1.25" body lift. Taking a straight edge along the top of the Savvy aluminum skid, I see I have about 1.25" inches for a crossmember section depth.



Time for a preliminary check of clearances… With the 1.25" inches of spacers under the isolation pads (0.25" plate + 2 x 0.5” wood boards), I jack up the Savvy skid onto the frame rails.




Last edited by Sahara Surfer; 08-27-2013 at 01:26 PM.. Reason: Wrong transmission type called out.
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Unread 08-25-2013, 08:13 AM   #2
Sahara Surfer
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Little close to the tub but still good…



Looks like the low profile cat leaves a lot of room for the crossmember.



If you are interested in math and engineering design, I have the crossmember stress calculation on the following link.

http://home.comcast.net/~juceda/Jeep...memberCalc.jpg

Short of doing computer simulation, I made a lot of conservative assumptions and simplified the problem to a box beam with pined connections at both ends with a maximum stress under the highest load under one of the isolation pads. I checked this bending stress against a fraction of the yield strength of the material per the AISC steel design manual.
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Unread 08-25-2013, 08:18 AM   #3
Sahara Surfer
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Enough of the nerd talk…, here is the fab work. I started out by cutting a 2 x 3 x 3/16 rectangular tube in half and laying sections of them on the Savvy skid:



The center section has to have access holes to tighten the bolts on the isolation pads. I reinforce those areas with ¼" thick tube to transfer the stresses. Note the interior reinforcement plate at the end. The bottom side will have internal plate reinforcement at the joints.



Assembled center section…



You can follow the progression. I have marked the location of the center section on the Savvy skid and use it as a reference guide. Note that the transmission mount is not centered. Also, I welded the ½" bolt sleeves made from ¼" thick tubes. These will tie in to padeyes welded to the 2 x 3 angles shown on the photo below. The angles will be fillet welded to the insides of the frame.

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Unread 08-25-2013, 08:23 AM   #4
Sahara Surfer
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Fish plates at the seams and top sections boxed in... Some of my welds are ugly, but they will hold.



I added tabs that will attach to the aluminum skid at four locations. I had to drill two new countersunk holes on the Savvy skid.



Finished crossmember… ready for painting.



I use Eastwood chassis primer and topcoated it with satin finish black paint.



Back to work on the frame mounts…



I made the padeyes from 3/16" thick angle.



Another view of the padeyes… with cheek plates about to be welded on.

Note the plug weld hole inside.

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Unread 08-25-2013, 08:27 AM   #5
Sahara Surfer
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Frame mount rails are now welded onto the interior sides of the frames.



This is an area that is prone to rust, so I covered it with POR-15 for protection.



A view of the finished driver’s side frame rail.



Savvy aluminum kid plate gets loving from Eastwood paints.

At this point, I need to stop and crack open the transfer case to install my SYE kit from JB Conversions. More to come!

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Unread 08-25-2013, 09:04 AM   #6
Unlimited04
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very nice work!


....btw, the 42RE (A500) is a 4-speed auto found behind 3.9L V6's and 5.2L V8's in trucks and vans, the 32RH (A999) is the factory 3-speed Jeep trans. Source.
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Unread 08-25-2013, 09:18 AM   #7
afusco1222
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Looks good. Maybe you can sell your design to Savvy.
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Unread 08-25-2013, 09:30 AM   #8
ctorres018
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Wow this is great work maybe savvy will finally make one for the 32rh, nice work post pics on after the install !
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Unread 08-25-2013, 10:23 AM   #9
hustler905
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Great work, I like an organized approach.
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Unread 08-25-2013, 10:43 AM   #10
yelset
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http://www.jeepforum.com/forum/attac...-armor-061.jpg

Good work. I took a different approach. A buddy of mine who has done quite a bit work on my jeep, built a custom trans mount bracket and did some work on the Savvy cross member. Love the way it performs.

Post 2276 http://www.jeepforum.com/forum/f9/sa.../index152.html
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Unread 08-25-2013, 11:58 AM   #11
Sahara Surfer
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All: Thank you for the encouragement!

Quote:
Originally Posted by Unlimited04 View Post
very nice work!


....btw, the 42RE (A500) is a 4-speed auto found behind 3.9L V6's and 5.2L V8's in trucks and vans, the 32RH (A999) is the factory 3-speed Jeep trans. Source.
Whoops, Google failed me! Don't I feel sheepish... Thank you for the clarification. Too bad I can't edit the thread title.

UPDATE ***Figured out how to fix the thread title. Still feel dumb.***
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Unread 08-26-2013, 06:50 AM   #12
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Great work man. Bumping this back up to the first page where it belongs.
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Unread 08-26-2013, 09:43 AM   #13
Sahara Surfer
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Quote:
Originally Posted by Imped View Post
Great work man. Bumping this back up to the first page where it belongs.
Thanks, Imped!
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Unread 08-31-2013, 03:06 PM   #14
Sahara Surfer
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The skid tie in bolts on the rear side of the crossmember will be difficult to reach, so I made the adjustable flag nuts at these locations. The bottom surfaces are coated with POR-15.



Once they are in place, I shot some weld through primer on top for rust protection. I then added some small welds to keep the flag nuts from sliding out.



Once I touch up the crossmember with black paint, it is ready to install.
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Unread 08-31-2013, 03:23 PM   #15
Sahara Surfer
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Crossmember installed

I finally finished my SYE install. It took me all day... If there was ever any doubt, lock rings are the devil. I finally got frustrated with the blasted things and in a fit of rage, I took at cut wheel to the OEM output housing. Good thing JB conversions gives you all new hardware at the output shaft.

Anyhow, that is done and I can install the new crossmember. Here is a view from the rear. Still clears the tub.



A view of the front side:



Another view of the back. That low profile cat kicks ar$$e!



Profile shot. All it needs is the Savvy skid.



I ran out of time and will have to test fit the skid later, my daughter is giving me dirty looks because Jeep time is cutting into daughter time. I still need to refill my transfer case with ATF, tighten some bolts on the cable linkages, and attach my front drive shaft. I love how I can now access this area while keeping everything supported.
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