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Bushing question: What are "secondary transmission crossmember mounts"?

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Old Jan 20, 2003 | 05:43 PM
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From: Fort Mill, SC, USA
Car: '88 Iroc, '91 RS, and a '70 RS
Engine: 5.7 TPI; 5.0 TBI; ZZ4/T56 on the ag
Transmission: A4, A4, slated to be a T56
Bushing question: What are "secondary transmission crossmember mounts"?

Anyone heard of these things? I got them with some other bushings on Ebay and the guy described them as "sway bar bushings".

I know that's not what they are, but I didn't know a 3rd gen had a secondary transmission crossmember.

Little help here...BTW, these are going right back on Ebay unless someone wants them.

Ed
Attached Thumbnails Bushing question: What are "secondary transmission crossmember mounts"?-35531109.jpg  
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Old Jan 20, 2003 | 06:37 PM
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Apeiron's Avatar
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From: Mercedes Norte, Heredia, Costa Rica
Car: 1984 Z28 Hardtop
Engine: 383 Carb
Transmission: 4L60
Axle/Gears: 3.54 Dana 44
I think I have a useless set of those too. Some cars had another piece (presumably the secondary crossmember) that went between the crossmember and the tranny mount. Those things went between the crossmember and the secondary crossmember.
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Old Jan 20, 2003 | 06:39 PM
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From: Fort Mill, SC, USA
Car: '88 Iroc, '91 RS, and a '70 RS
Engine: 5.7 TPI; 5.0 TBI; ZZ4/T56 on the ag
Transmission: A4, A4, slated to be a T56
Thanks man...Ed
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Old Jan 20, 2003 | 10:21 PM
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82camaro's Avatar
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From: NE
Car: 82 camaro SC
Engine: 350
Transmission: 700r4
It would make more sence if they were called"secondary transmission mounts" A 'mount' mounts to the crossmember with two bolts using these bushings, then the 'primary' tranny mount, hooks to the middle of this and the tranny. Not sure why they did it though. Mine has them, but I switched to poly already--or I'd buy them.
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Old Jan 20, 2003 | 10:55 PM
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From: Rowlett, TX
Car: 1988 GTA
Engine: 5.0 TPI
Transmission: T5
Axle/Gears: 9 Bolt, 3.45
They are for a six cylinder third gen with automatic transmission. If you look at the crossmember on a V6 car, there is a small crossmember bolted ontop of the normal one, and those bushings go between the 2. The transmission mount bolts to the smaller crossmember.
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Old Jan 21, 2003 | 12:41 PM
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ebmiller88's Avatar
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From: Fort Mill, SC, USA
Car: '88 Iroc, '91 RS, and a '70 RS
Engine: 5.7 TPI; 5.0 TBI; ZZ4/T56 on the ag
Transmission: A4, A4, slated to be a T56
Thanks Ward, that clears things up.

Ed
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Old Jan 21, 2003 | 01:49 PM
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RB83L69's Avatar
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From: Loveland, OH, US
Car: 4
Engine: 6
Transmission: 5
They were also used on my 83 HO 5-speed.

They seem to have been used on some, but not all, 82s and 83s. I don't recall ever seeing them on a 84 or newer. They may have to do with assembly plant even, or some such. My car is a Van Nuys car.
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Old Jan 22, 2003 | 01:17 AM
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zed
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From: Antioch, CA, USA
Car: 1991 Z28, 1984 Z28, 1990 Toyota 4x4
Engine: L98, L69, 22RE
Transmission: 700R4, 700R4, 5Speed Manual
Axle/Gears: 3.73, 3.23 Posi, 4.10
both my '84 and '85 with LG4/700R4 use these mounts. don't know why some cars have them and some don't tho.

c-ya

zed
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Old Jan 22, 2003 | 07:03 AM
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ebmiller88's Avatar
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From: Fort Mill, SC, USA
Car: '88 Iroc, '91 RS, and a '70 RS
Engine: 5.7 TPI; 5.0 TBI; ZZ4/T56 on the ag
Transmission: A4, A4, slated to be a T56
I've never seen them on the cars I've had ('83, '88, and '91) but I never got under that '83 either...


Anyone want them for cheap? They're new and run $17.99 at Jeg's.

Make an offer...I'm easy.

Ed
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Old Jan 22, 2003 | 07:16 AM
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From: Rowlett, TX
Car: 1988 GTA
Engine: 5.0 TPI
Transmission: T5
Axle/Gears: 9 Bolt, 3.45
My sisters 87 SC 2.8 700R4 has a crossmember like this. I've never seen a V8 car with one, only V6's.
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Old Jan 22, 2003 | 06:20 PM
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From: Central NJ, USA
Car: 1986 Firebird
Engine: 2.8 V6
Transmission: 700R4
I've seen v8 cars with 'em, too. Here's the deal. Know how our trans mounts have a single center screw that goes into the crossmember? Over time, that center hole in the crossmember could take too much stress, fatigue, and crack.

This "secondary crossmember" was meant to take the stress off the center bolt of the trans mount. What happens is, instead of a crossmember with a center hole, you get a crossmember with two holes, about 3 inches away from where the center hole would've been, on each side. A secondary trans mount bolts to these holes via some bushings. Then, the main trans mount- the three bolt job that we're all used to- bolts to the secondary trans mount. In fact, the main "real" trans crossmember is modified; they cut the center a bit wider so you can poke a socket up thru the middle, to unbolt the trans mount from the secondary x-member.

So the main, "real" crossmember doesn't get stress from one bolt hole anymore. It gets two bolt holes, to divide the stress.

I haven't seen these on early cars; I usually see 'em on later f-bodies, around the 88-89 era. My '86 2.8 v6 doesn't have one.
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Old Jan 22, 2003 | 06:25 PM
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From: Central NJ, USA
Car: 1986 Firebird
Engine: 2.8 V6
Transmission: 700R4
Here's some links from our v6 board, we've hashed this question over a few too many times.

Here's Dale, and his dealings with this secondary trans crossmember- with a picture! https://www.thirdgen.org/techbb2/sho...hreadid=128834

Notice Ashkay and his old crossmember with the huge hole in the middle: https://www.thirdgen.org/techbb2/sho...hreadid=128667
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Old Jan 22, 2003 | 09:56 PM
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laiky's Avatar
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i got them on an 84 lg4 and an ho, i don't recall not seeing them. they are quite inconspicuous though.
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