Transmission mount...solid?
Thread Starter
Melting Slicks
Joined: Sep 2004
Posts: 2,655
Likes: 19
Transmission mount...solid?
I'm installing a Richmond 6 speed attached to an LS motor with polyurethane motor mounts. With my crossmember, it would be easiest to just use a solid spacer to mount the trans. The standard 1 3/4" mount will be too tall.
Any problems with mounting the trans solid to the crossmember?
With the poly motor mounts, there shouldn't be a lot of movement of the motor, so I wouldn't think breaking the transmission mounting tabs would be a problem.
Any problems with mounting the trans solid to the crossmember?
With the poly motor mounts, there shouldn't be a lot of movement of the motor, so I wouldn't think breaking the transmission mounting tabs would be a problem.
Tech Contributor
Joined: Jun 2004
Posts: 20,855
Likes: 959
From: I tend to be leery of any guy who doesn't own a chainsaw or a handgun.
I'm installing a Richmond 6 speed attached to an LS motor with polyurethane motor mounts. With my crossmember, it would be easiest to just use a solid spacer to mount the trans. The standard 1 3/4" mount will be too tall.
Any problems with mounting the trans solid to the crossmember?
With the poly motor mounts, there shouldn't be a lot of movement of the motor, so I wouldn't think breaking the transmission mounting tabs would be a problem.
Any problems with mounting the trans solid to the crossmember?
With the poly motor mounts, there shouldn't be a lot of movement of the motor, so I wouldn't think breaking the transmission mounting tabs would be a problem.
Melting Slicks
Joined: Oct 2002
Posts: 2,317
Likes: 111
From: St Louis MO
A solid transmission mount will cause additional stress and flexing through the bellhousing area - especially with an automatic. If you have ever seen an automatic case with a crack - it's not pretty. Use the stock trans mount instead (I don't even like polyurethane).
Further, I have very little faith with solid motor mounts either. A few years ago, I added a popular brand of solid motor mount to my 406 SBC engine in a C2. In approximately 6 months, one had crack about 45% through one of the vertical legs near the bend. I replaced the mounts using (newer fail-safe) rubber mounts - haven't had a problem since.
Thread Starter
Melting Slicks
Joined: Sep 2004
Posts: 2,655
Likes: 19
Makes sense. It looks like I might have to try to find a lower profile mount or modify an existing one.
Anyone know of a lower profile trans mount?
Anyone know of a lower profile trans mount?
It isn't the motor movement you need to worry about. These frames have a crappy torsional strength level, and if you drive it hard, or hit an apex curb on the track, the frame will twist, and your engine/trans will act as an involuntary torsion bar down the middle of the frame. The tailshaft is not designed to function as a torsion bar. If you are a slow/easy driver, you might be fine. But, the solid trans mount concept scares me.
Le Mans Master
Joined: Jan 2005
Posts: 8,226
Likes: 2
From: Lake Wylie SC
As one moves the other needs to move the same way........ difficulty shifting at RPM and vibrations will be both the start and the least of the problems associated with a motor that moves and a transmission that does not
Doug
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Tech Contributor
Joined: Jun 2004
Posts: 20,855
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From: I tend to be leery of any guy who doesn't own a chainsaw or a handgun.
I just cut and reshaped my (bolt on) trans bracket when I put in my DN5spd a bunch of years ago. IIRC, the Richmond 6spd has a somewhat similar tailhousing shape, so a bit of bracket cutting and welding should get you where you need to go.
Le Mans Master
Joined: Jan 2005
Posts: 8,226
Likes: 2
From: Lake Wylie SC
It isn't the motor movement you need to worry about. These frames have a crappy torsional strength level, and if you drive it hard, or hit an apex curb on the track, the frame will twist, and your engine/trans will act as an involuntary torsion bar down the middle of the frame. The tailshaft is not designed to function as a torsion bar. If you are a slow/easy driver, you might be fine. But, the solid trans mount concept scares me.
Thanks for sharing that
Doug
Le Mans Master
Joined: Dec 2003
Posts: 5,727
Likes: 38
From: Fremont CA
DON"T DO IT! Even on race Vettes with solid front mounts I run a std rear mount to prevent cracking of the transmission tailhousing. I will just about GUARANTEE you that this will happen if you go to a solid mount.
