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General Forums => The Mess Hall => Topic started by: neale_rs on March 15, 2013, 05:25:47 PM
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Currently, the transmission mount bolts go through my skid plate. They are protected by some metal ramps but the part of the ramps closest to the bolts is a sharp edge and it hangs up on rocks:
(http://i138.photobucket.com/albums/q277/neale_rs/000_0575.jpg)
I'm going to grind down the sharp edges to a bevel for now but it may be better to get everything above the skid plate eventually.
Here is a picture of what I would like to do. The blue things are rubber donuts, they would be raised off the bottom of the skid plate to keep the same height as with the stock transmission mount and to allow the nuts to be above the bottom of the skid plate. The bolts would tighten on a sleeve just barely compressing the rubber donuts.
The one thing that bothers me about the design is that the 3/8" plate would be in metal to metal contact with the sleeves. Would this be ok? All comments/opinions are appreciated.
(http://i138.photobucket.com/albums/q277/neale_rs/Transmount_tiff_zps8a5b72f9.jpg)
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you can also weld something a bit higher right where the holes are now and sink the bolts, it would raise your transmission and t-case by 1/2 an inch let's say (don't know if you have room), you can achieve this with a 1/2'' flat bar in which you machine a recess about 1/4 inch or so, add that to your existing skid thickness and it's what the head of the bolts should be at. The other option is to use coutersunk bolts, you can probably get away with a 1/4'' flat bar welded to the skid in that case.
I like your idea and would add to the torque rotation resistance, my suggestion is just cheaper way (i think) and reuse your mount, don't mean or think it's better.
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With the custom skid plate, there is no room to raise the trasmission more, its in there pretty tight. The other complication is that the rear support ring for the Atlas would have to be redone.
My description was a bit misleading. What currently goes through the skid plate is the pair of studs that are part of the transmission mount, with the nuts being under the skid plate. But your ideas do make me consider just changing the ramps to something with round holes in it instead of a straight across sharp edge. Something like that should hang up less.
I've also seen some poly mounts that have threaded holes instead of studs so that bolts from the bottom can be used. Then some countersunk flat head bolts could be used, like you suggested.
Thanks for the ideas.
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Well you could put a wedge with a hole bored into it. Not through it. Then have smaller flush bolts that hold that to the plate.
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With the custom skid plate, there is no room to raise the trasmission more, its in there pretty tight. The other complication is that the rear support ring for the Atlas would have to be redone.
My description was a bit misleading. What currently goes through the skid plate is the pair of studs that are part of the transmission mount, with the nuts being under the skid plate. But your ideas do make me consider just changing the ramps to something with round holes in it instead of a straight across sharp edge. Something like that should hang up less.
I've also seen some poly mounts that have threaded holes instead of studs so that bolts from the bottom can be used. Then some countersunk flat head bolts could be used, like you suggested.
Thanks for the ideas.
i hope you can find 1/4 inch there, if you can then it's a matter of welding it on the other side and countersink the holes, you can machine down the head a bit if it sticks out, the hex has a champher so it's not really helping with holding the allen socket in the bolt - there is a problem with this though, if you go over rocks and scrape the bolts you might have trouble taking them off.
keep us posted, i need to make a custom skid too and i'm looking for a clean solution
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Well you could put a wedge with a hole bored into it. Not through it. Then have smaller flush bolts that hold that to the plate.
A cover, this is an interesting idea. Thanks
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i hope you can find 1/4 inch there, if you can then it's a matter of welding it on the other side and countersink the holes, you can machine down the head a bit if it sticks out, the hex has a champher so it's not really helping with holding the allen socket in the bolt - there is a problem with this though, if you go over rocks and scrape the bolts you might have trouble taking them off.
keep us posted, i need to make a custom skid too and i'm looking for a clean solution
Will have to think this over for a while but will eventually post what I finally do. Thanks
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You have a tile floor in your garage??? Mad props. :beers:
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Currently, the transmission mount bolts go through my skid plate. They are protected by some metal ramps but the part of the ramps closest to the bolts is a sharp edge and it hangs up on rocks:
(http://i138.photobucket.com/albums/q277/neale_rs/000_0575.jpg)
I'm going to grind down the sharp edges to a bevel for now but it may be better to get everything above the skid plate eventually.
Here is a picture of what I would like to do. The blue things are rubber donuts, they would be raised off the bottom of the skid plate to keep the same height as with the stock transmission mount and to allow the nuts to be above the bottom of the skid plate. The bolts would tighten on a sleeve just barely compressing the rubber donuts.
The one thing that bothers me about the design is that the 3/8" plate would be in metal to metal contact with the sleeves. Would this be ok? All comments/opinions are appreciated.
(http://i138.photobucket.com/albums/q277/neale_rs/Transmount_tiff_zps8a5b72f9.jpg)
Use flathead bolts with the nuts on top. You use a countersink drill on the bottom of the skid plate, stick flathead bolts in from the bottom, nuts on top with red loctite if need be for added security, so the bolts won't fall out and the problem is solved.
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You have a tile floor in your garage??? Mad props. :beers:
Makes cleaning up the oil spills easier, :biggrin:
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Use flathead bolts with the nuts on top. You use a countersink drill on the bottom of the skid plate, stick flathead bolts in from the bottom, nuts on top with red loctite if need be for added security, so the bolts won't fall out and the problem is solved.
So the same design with the rubber donuts but using flat head bolts from the bottom.... That would avoid the holes in the skid plate and be smoother overall. Thanks for the idea.
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If at all possible always KISS it.
No need to make things more complicated than they need to be.
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If counter sunk flat head bolts are used from the bottom, this would allow the rock catching nut protectors to be removed:
http://www.4wd.com/Jeep-Drivetrain-Jeep-Axles-Differentials/Polyurethane-Transmission-Mount.aspx?t_c=12&t_s=505&t_pt=3617&t_pn=D%2fI7-1604-BL
It says it works for 72 to 95 CJs and YJs so this one for 71 to 86 CJs would most likely also work and is cheaper:
http://www.4wd.com/Jeep-Drivetrain-Jeep-Axles-Differentials/Rubber-Transmission-Mount.aspx?t_c=12&t_s=505&t_pt=8004&t_pn=OAI18608.02
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I would try to make a low pro mount with the rubber or urethane blocks on either side of the trans mount pad
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Might as well, it most likely controls torque better too.
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These look like they could work:
http://www.4wd.com/Jeep-Lift-Kits-Jeep-Lift-Kits-Suspension/Body-Cab-Mount-Set.aspx?t_c=1&t_s=20&t_pt=6963&t_pn=ENE2.4101G
Or this, which would provide some side to side cushoning, but it's made for a 1/4" plate. Would 1/4" be good enough?
http://www.energysuspensionparts.com/proddetail.asp?prod=9.4102
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the second one
http://www.energysuspensionparts.com/proddetail.asp?prod=9.4102
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That one looks really good. Do you think a 1/4" plate would be good enough? I kind of think so....
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Have decided to try Jeffy's idea of making a cover for the bolts but made out of HDPE instead of steel.
My plan is to buy a 1/2" thick cutting board and go from there.
So how hard is it to cut and shape that material?
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you're overthinking it, just replace the bolts with flat head ones, countersink the holes and you can even leave those wedges in. worst case scenario add a 1/4'' plate if you dont have enough room to countersink the holes and weld tack it in place (but i did it on 3/16 plate so it should be enough room in your case since is 1/4'' thick if i remember correctly). if you meet a rock that hdpe cover will be gone anyway.
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So countersinking into 1/4" would be strong enough? This would allow me to do this project without involving a shop to do the welding.
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So countersinking into 1/4" would be strong enough? This would allow me to do this project without involving a shop to do the welding.
yes, it would be strong enough, what i don't know is if there's enough thickness to have all the 80deg part in the plate and not sticking out into the mount. I think those are 7/16 bolts in the stock mount
here's a pdf with the dimensions http://www.electroimpact.com/company/QMS-0003.pdf (page 5) - the head is .234 high so if you're careful and don't go below the level of the plate when you countersink it should have enough room to tighten the mount before it bottoms out.
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Thanks. That's a very good PDF too.
Ok, so stregthwise it is good but
.234 seems too risky to do by hand drill. The other thing is that I would need to get this mount:
http://www.4wd.com/Jeep-Drivetrain-Jeep-Axles-Differentials/Polyurethane-Transmission-Mount.aspx?t_c=12&t_s=505&t_pt=3617&t_pn=D%2fI7-1604-BL
so that bolts could be used from the bottom. The mount in the Jeep now has non-removable studs with nuts under the skid plate. Since the transmission mount would have to be changed anyway it might be better to go with a pair of these:
http://www.energysuspensionparts.com/proddetail.asp?prod=9.4102
To use these would require .250" spacers anyway (to duplicate the height of the stock mount) so going too deep on the countersink could be handled by opening up the hole in the spacer. Overall, getting the spacers welded in as you said might be needed seems like the best way, although I would need to get this done by someone.
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if you change the mount it will work, it has a little bit of countersink in it just enought to keep you from worrying. The other ones would work too but you'll have to make the mount really strong (as it extends away from the transmission), they're lot stiffer than the stock mount with very little "give". You can countersink by hand, use a good variable speed drill with the speed setting to low (high torque) - go little by little and check the shape, you can see if you're not centered or off from perpendicular by the shape and make corrections, is not ideal but works ok and it doesnt' have to be perfect.
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Thanks, that gives me more confidence to do it this way. I'm going to start gathering the parts and tools.