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Hey Guys, I wanted to share this info with all of you. I did a lot of searching for answers and found this subject had come up many times over the years here on the forum both in C3 and over in C2. It may save some of you a lot of grief in the future. If you have to replace your transmission mount, which is a fairly common wear part on both automatics and standard transmissions, check for this design flaw before you install. GM no longer offers the original 3792133 mount, so only aftermarket is available to us.
Just got my car back on the road last week and I was trying to run down a noise transfer that I would swear is a bad transmission mount. But it's brand new and looks like a good quality after market piece.
So I start to do some homework and decide maybe this mount is a bit too tall, and it's pushing the exhaust hanger bracket up to the point where the exhaust pipes are touching the cross member ports.
I check it and the pipes look pretty close. I remove the mount and measure it, it is 1 3/4 tall. So I reach out to the forum members here for a measurement of an original mount and almost instantly Richard454 (many thanks brother) sends me this pic of his almost new, original mount and it is the exact same height as my after market piece, so I have to rule that out.
I start to look closer at the part I have and check the separation of the two steel pieces. I will call them steel part "A" and steel part "B" here just for clarification.
I know that the orig. mount did not have a bottom to the threaded holes as this one appears to and it looks like both of the arrows point to part of steel "B'.
I use a slim punch to tap steel B and get the expected bounce. I tap the bottom of the hole and it is rock solid. So the bottom of the hole is part of steel A. This looks bad as I use a pick to determine there is literally a hair's breadth between these two pieces of steel.
What looked like extra rubber flashing at the bottom of the hole is actually the only area NOT in contact from steel A to steel B.
I can see the mounting bolts have actually scraped the bottom of the bore touching steel A together with steel B making them one solid piece ! How can this be?
So I check the bore depth.
And find I only have about a half an inch. Difficult to tell by this pic as my camera focused on the higher plane, but there is a mark from the stock original mounting bolt bottoming against the lower piece, where the white arrow points.
So I've been able to determine that although this looked like a very good quality part, it's design is completely without research or test fit as to functionality.
In short, it is junk.
I will order another mount from a different source tomorrow but I'm convinced I've located my problem.
Cheers, Greg
Greg,
Very nice write up and tutorial on the trans mount. I have a nos due to go in mine someday. I have what I believe is the orig mount currently and have 88k on her now. I want to change it out for good measure as well someday. Great info, thanks again.
Marshal
Is that an energy suspension poly mount?
Have one but it transmitted vibration (poly engine mounts).
Canf find a good rubber one...even the Napa pieces are junk from China....threads dont know if they are standard or metric somewhere in between lol
i just did min e a few months ago rubber..
rockauto made in korea it said on side..seemed pretty accurate when i put it in..remeber OEm was hollow under it too.. this one kinda carved out?
it is less than 4 bucks not including shipping.. and not China.. could not locate USA mount..
@Greg or @marshal135
Would you have any NOS or original pics of the rubber form the side ( how solid or deep)? I am still tracing a high speed shifter vibration and wondering if my Korea Anchor mount is too loose or too tight?
Impossible to find USA or NOS.. so my collection is starting on differences..
It almost seems the aftermarket too solid? but forgot to document my original before i tossed it..
thanks!
Bought a mount from LIC for my 67 (non side pipe.
Body was off trame so it was easy, but the exhaust would not fit thru the frame. Checked the part # and it was correct.
Went to local auto parts with it and their hight was different and half of what I paid from the vette vender. Problem was solved, so I called the vender to let them know that the part # was wrong and I got a very RUDE remark. It ended with them saying they don't make mistakes.
Their mistake cost me hours, and I still have the bogus mount.
I don't get it. I would gladly pay double for a good part made in North America. These aren't grocer-getters owned by people on a tight budget, there are our babies. Why doesn't somebody make good quality parts for us????????
here is a new napa one..
China..
the measurement i get is over 2 inches where i see Greg posted 1.7"
would love to know what a manual mount should be and not a universal mount auto /manual.. Was there a difference auto to manual? height? other?
Not sure what my Korea one i installed is but will try to look later..
anyone have that? i really wish i didn't toss my old one for a manual.
Yeah I remember the grief that it was to get a good mount- 18-20 years ago. Back then things were just starting to go South, meaning more and more parts were imported but there were still quality USA made parts. No so much today.
The ES mount I bought I think is still on my parts rack somewhere. There was no way that part, 19 years ago was going to work in my 72 with TH400. Although the summit catalog online said it was universal. The same lousy customer service we get today from many online vendors was a problem then too. There was no one at Summit at the time that could do anything but read off a line card. I had to call ES directly, get a hold of a product engineer only to have him tell me the Summit listing was wrong and that mount would not work on a corvette. Prothane had one that was the same dimension as GM and I used that.
I think I stashed a GM rubber mount away but I would have to go look for it.
Many, many parts we took for granted growing up with these cars are no longer the same quality. No surprise there I guess. People ask me why I rebuild new out of the box posi's!
so i quickjacked to see my Korea rock auto mount i put in a while back..
interesting things i didn't notice before;
- Best i could measure with weight on mount (whatever that is..) i get ~ 1.85"
- The damn thing is SOLID! there will be limited squish and assume not much vibration control on shifter??? (over 80 MPH). the picture shows not solid..
the search continues.. hollow mount rubber right size. Heh Gary, i'll take that mount if for sale and you ever find it!
will update searches..
maybe put the short poly in and drill some holes to hollow it?
interpon, I can't tell by your pictures, but are you having issues with your exhaust touching the cross member due to the trans mount height? I was and that's where my noise transfer/vibration was coming from.
Koreans are known for making great kimchi, not for making great transmission mounts for American muscle cars.
I shall look when up again. GREAT POINT
I use ss worm clamps to hold tight against exhaust hanger as i use band clamps instead of standard exhaust clamps.The u bolt type indent the pipes and you cannot get off and on and still a PITA with these.. but doable. not that i remove them often!!!
round 4 O'reilly's coming and if 1.8 or less and hollow i will be changing..shall report..
really researched a lot and many rebranded same type.. NOTHING on ebay...
Hell, i would have thought Korea better than China or India??
i did find some pics when i went to duals and added bracket with 2 sides. that original sure looks lower.. 28000 miles here
Last edited by interpon; Apr 20, 2022 at 09:27 AM.
Looks like enough clearance currently in holes.. could be a little lower. with no hollow mount there is no give so hoping new hollow 1.8 or less will help more if it can slightly crush. passenger side higher for some reason.
if i put that chinese 2 incher on it would be almost touching!
Last edited by interpon; Apr 20, 2022 at 11:15 AM.
I agree, that looks like enough clearance.
Damn, I just realized that I did not do a follow up post to my original. I should have posted which mount I ended up getting and that it did solve my vibration/noise transfer problem. I'll dig through my file on this car today and see if I can find the correct receipt with source and part number.
Cheers, Greg
ding ding ding!!!
we have a winner..
Chinese Oreillys A2378 Power torque brand!!! https://www.oreillyauto.com/detail/c...?q=a2378&pos=0
- measures 1.75"
- has a cutout similar to OEM (more air less rubber)
- the Napa one is 0.14 " thick metal (2.25" width overall) and the power torque is 0.1 " (2.37 overall width). i don't see this as a big deal.
I can even slightly move the power torque one by pressing on it where the Napa 2 inch has less opening and very ridgid. And of course the Korea anchor is solid..so no give there..
getting closer!
EDIT.. i did review all sponsors and most carry the anchor Korea solid.. no USA anywhere
Last edited by interpon; Apr 20, 2022 at 03:41 PM.
All Mounts Are NOT Created Equal
