Topic: Opinions on transmission mount

[neale_rs]

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:



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.

[sharpxmen]

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.

[neale_rs]

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.

[Jeffy]

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.

[sharpxmen]

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

[neale_rs]

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

[neale_rs]

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

[JohnnyO]

You have a tile floor in your garage???  Mad props. 

[aw12345]

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:



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.

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.

[neale_rs]

You have a tile floor in your garage???  Mad props. 

Makes cleaning up the oil spills easier, 

[neale_rs]

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.

[aw12345]

If at all possible always KISS it.
No need to make things more complicated than they need to be.

[neale_rs]

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

[aw12345]

I would try to make a low pro mount with the rubber or urethane blocks on either side of the trans mount pad

[neale_rs]

Might as well, it most likely controls torque better too.