Transmission Mount

[scoutboy74]

I have the RPT trans mount in Hooty with functional, stock engine mounts. If ever there would be a chance for such vibrations (non-original engine swap) this rig would exhibit them. Happily, there are none. Jeff is right. The mounts don't cause drive train vibrations. They may amplify them, but the root cause lies elsewhere.

[mike4514]

I understand that the mount itself will not cause a vibration, but it will transmit the motor vibrations to the frame of the truck if they are very hard and basically a solid mount. My question was if it is put together correctly or is it normal for this type of mount to transmit vibrations through it without dampening the vibrations.

I had a rubber mount installed in the truck when I decided to install this new mount. With the rubber mount there were no engine vibrations in the cab, after installing the mount there is a lot of vibrations in the cab. It feels the same as installing solid steel mounts. It just seems that vibrations will travel right through the bolt to the cross member since there is no isolation from the bolt to the cross member. Shouldn't there be some type of rubber under the cross member to isolate the bolts? This is the same thing as welding a rod between the two plates with some hard rubber between them. Thats why it seems to me I am missing part of this mount, the part under the cross member.

Wouldn't a mount that is designed to dampen vibrations had a seperation between the tranny and cross member of some type of rubber or poly material so they are not directly connected? This mount is directly connected metal to metal through the bolts.

[Ristin]

Maybe you are getting some vibration because that incorrectly installed trans mount is lifting the trans up and changing angles. On our big trucks at work, if the the air ride suspension gets out of whack and rides to high or to low, we get bad drive train vibration.

I also have RPT engine mounts and trans mount on my 78 Terra. I have no vibration issues at any speeds. Well, up to 80 mph anyway, that's as fast as I have been brave enough to run up to.

[sullyscout77]

Mike4514, Like Jeff said, the white piece goes below the cross member, not on top like your picture shows! You've got your tranny jacked way up, throwing off your drive line.

[mike4514]

I completely missed Jeffs post.. I bought the mount and cross member as is, the PO put it together and I just installed it as a package. That makes sense now. I didn't have a clue to the right way it should be installed so thats why I posted, looks like I was right that something was not the way it should be.

This weekend I will switch it and report back.

Thanks all for the help.

Just for the record, my vibrations were all with the truck in PARK. So drive train was not involved.

[mike4514]

Update: This weekend I took the mount apart to switch it to the correct configuration and found that the sleeve did not fit through the tranmission cross brace.

I called IH Only North and talked to Mike, great guy very patient with my problem. The mount has 5/8" sleeves and the holes in the cross member are 1/2", no wonder it didn't fit and the PO put it in the way he did. Mike checked some cross members he had for a Scout II and the holes were bigger than the ones I have. The mount sleeves measured the same as the ones Mike had. Both the cross members I have are the 1/2" holes. They are from a 73 and 75 Scout II. It looks like I would have to drill out the cross member to use this mount.

I cleaned up my old mount and it was not in bad shape at all so, I decided to put that one in and call it good. Now my vibrations are gone and it works great. It looks like there are differences in the cross members.

If anyone is interesed in a used but in good condition RPT mount, drop me a PM.

[Jeff Ismail]

Early versions that had either the T18 4 speed manual transmission or the 727 auto used a slightly different mount that had two studs coming from the bottom of it. Later when IH switched to the T19 they used a different mount along with the auto that had much larger holes in the crossmember. For those with the early version we use a die grinder to open up the holes so that the sleeves will fit thru. Just wanted to post this so that future users who search for this info have a definitive answer on how to make the RPT mount work.

[mike4514]

Thanks Jeff,

The mount sure looks like a good mount and now it makes sense why the PO put it together the way he did. Again, thanks to Mike at IH Only North for helping me figure out what was wrong.