Are the T18 and C6 transmission mounts interchangable?

[robroy]

Hi! Does anybody happen to know if the T18 and C6 transmission mounts are the same on our trucks? Or are they different from one another?

Following a great suggestion from Fordman, I did some part number research. I found that the part numbers were different between the C6 and T18 for some vendors and the same for others--here's the rundown:

1. LMC Truck: Different
2. NAPA: Different
3. Rockauto.com: Different
4. Advance Auto: Different
5. NPD: The same!
6. Dennis Carpenter: The same!

So this isn't much to go by. Does anybody have practical experience with this?

Thank you!
-Robroy

[cdherman]

If its any help, the tranny mount from my BW t-18 was correct to be swapped over to my C4 tranny when I made that swap. So it looks like Ford was wise enough to use a pretty standard setup, so I *think* that C6 might be the same too.

Of note, the C4 was from a Mustang and quite a bit later era, and the mount from the Mustang was NOT correct. What was correct, was the bolt spacing on the C4. It was the same as the T-18. I just removed the rubber/steel mount from the t-18 and bolted it to the C4. The correct holes for the cross member were already in my frame as well.

[fordman]

post a pic of your t18 mount and i'll look at it and see what i can tell as far as differences. i think the differences in some mounts are the bolt holes on where it fits onto the trans. so if you moved the crossmember any mount would work. but who wants to drill new holes for the crossmember?

[robroy]

Cdherman and Fordman, thanks!

I'll take some photos of the T18 mount and post 'em.

Thanks again,
-Robroy

[Hawkrod]

In the case of many Ford mounts, they are often dimensionally the same but made from different rubber compounds. That situation comes up often in Mustang circles. For example the 68-70 390/428 mounts are superceded by the 71 429 mounts. They look the same but the 71 mounts are made from a different compound. For that matter the 67 look the same but had long ago been superceded by the 68 mounts. It is simply a case of a component being engineered to resolve a situation. Stick shift and auto trans have different issues such as harmonics and manipulating the rubber can prevent customer complaints. Unfortunately the aftermarket does not always see this as important and often makes replacements all from the same compounds. The other issue is errors in the replacement parts books. Many companies source their parts from a third party who produces the parts and application books. Unfortunately if they make an error then everybody that buys from them usually duplicates the error. Hawkrod

[robroy]

Hi Hawkrod! Great information, thanks. I hope that's the case with this mount, since the difference in materials won't be applicable to the upgrade mounts (and if your info applies to these mounts, I have nothing to worry about regarding mounting holes and installation).

At the moment I have two Bumpside transmission mounts. One is the factory mount installed under my T18 in the truck. The other is a mount I bought from LMC (I think) about ten years ago. I bought it for a 1968 F100 360/C6 project truck I had for a while, so I think it's designed for a C6. Either that, or it's one of the universal mounts that's supposed to work for either transmission.

The existing, factory T18 mount:




The mount I ordered for the C6 years ago (the Made in Thailand part isn't confidence inspiring to say the least):









From what I can see, these two mounts look the same. But I really need to pull off my T18 mount to do a proper side by side comparison.

Any comments? Thanks very much!

-Robroy

[fordman]

that lmc mount is offset to bolt onto the trans. the c6 bolt holes are in a straight line with center. so there is the difference. they are different with those pics. it looks like the lmc mount is the same as a 3 speed mount with the offset holes.

[robroy]

Hey Fordman! Thanks very much for the information! It's good to know that the C6 mount holes are centered instead of offset.

It's plausible that the "C6" LMC mount I have is really for a 3 speed transmission--they could have shipped the wrong part years ago.

It sounds like it's a good idea for me to look at my T18 mount and determine whether those holes are centered or offset. I took all the photos I could over the weekend but I don't think they're at a proper angle to indicate whether or not the holes are offset.

If anybody else happens to have this information it would be very helpful, since I won't be able to look at my truck again until Saturday. I wish I had space for it at home!

Thanks again Fordman,
-Robroy

[robroy]

Hey Fordman!

I found a photo that shows this characteristic of my mount:



I think this indicates that my T18 mount has its transmission bolt holes offset towards the rear, just like the mystery LMC replacement.

Do you think I'm interpreting the photo correctly?

Thanks again for all your great help,
-Robroy

[fordman]

you are right. it is offset to the back. just like this pic of fordtrucks 3 spd trans. you can see how it is offset also.

[FordTruck]

Hi Hawkrod! Great information, thanks. I hope that's the case with this mount, since the difference in materials won't be applicable to the upgrade mounts (and if your info applies to these mounts, I have nothing to worry about regarding mounting holes and installation).

At the moment I have two Bumpside transmission mounts. One is the factory mount installed under my T18 in the truck. The other is a mount I bought from LMC (I think) about ten years ago. I bought it for a 1968 F100 360/C6 project truck I had for a while, so I think it's designed for a C6. Either that, or it's one of the universal mounts that's supposed to work for either transmission.

The mount I ordered for the C6 years ago (the Made in Thailand part isn't confidence inspiring to say the least):









From what I can see, these two mounts look the same. But I really need to pull off my T18 mount to do a proper side by side comparison.

Any comments? Thanks very much!

-Robroy

That's weird my C6 mount is way different than that. The one I got for my truck was alot like the one that came off of my FMX.
Here's my C6 mount

[fordman]

that mount is broken it looks like to me. all of them i have seen bolt through the crossmember in that bolt hole. but you can see where your bolts are center where it bolts into the transmission.

[FordTruck]

that mount is broken it looks like to me. all of them i have seen bolt through the crossmember in that bolt hole. but you can see where your bolts are center where it bolts into the transmission.

It shouldn't be broken I bought in brand new from O'reily's this summer and that's the way it came. My one that came on my FMX was broke becuase the bracket that the tranny bolts to you could spin it around and take it out it was broke How could that hole be in the center it way offset.

Here's more of the mount


The FMX mount was drilled a few different times


I put my C6 mount in the FMX mount holes and this is what happend.

I don't know why but my drive shaft wasn't crooked before but its driving fine so I just went with it.

[fordman]

that isnt a c6 mount. not like one i have ever seen. i have never seen a mount with holes drilled in the top either. the c6 mount is similar to the one rob got from lmc. did you put your crossmemeber in backwards to make it set like that. maybe that was the problem too.

[FordTruck]

Hmm I don't know well I'm afraid that I may have to drop my tranny someday and check out that whine. I don't know I guess its possible I could've put it in the wrong way. Someday I'll redo that whole mess. Yeah I guess there close to the same the olny difference is how it mounts to the cross member.