Group N Transmission height issues

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BSOD2600
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Group N Transmission height issues

Post by BSOD2600 »

Searching the forum for people who have installed the 'group n transmission mount', it seems to be mixed. Lots state afterwords their 3" DP bangs against the tranny/driveline. Others say there is no problem. A few posts I found, stated the group n is ~0.25" taller than the stock one.

I found this over at nasioc:
Image

Does anyone have the height measurement of the stock transmission mount for our car? Or is it just like the one on the far right in the picture and 3.250" high?

Depending on the stock height, it might be better to get 6-speed mount, since its 0.25" shorter, instead of the 5-speed one I assume most get. Thoughts?

'11 WRX Limited
'94 SS | 3" TBE, 07 TMIC, TD05H-16G, Revtronix Stage 2, Walbro -- Sold
'94 TW | R.I.P.
farfrumwork
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Post by farfrumwork »

I had installed a Group N (5spd) and had to remove it as it caused contact with my driveshaft (unsettling noises for sure).

I always thought that it was due to the stock mount being able to compress more, and the Group N mount holding the driveline up higher.

I liked the feel of the mount, so maybe I'll try it again with the 6spd version. I was going to compress the stock mount and fill it with the windshield seal material for a DIY fix, but I'd rather just swap a "lower" verison straight in.

What do the 6spd mounts run$$?


BTW, anyone want a 5psd Group N mount? <500mi total on it, $40 + shipping. It's been taking up spce in my garage for years now.

-Chad
Old - '93 T-Leg - 14.693 @ 92.68 at 5800ft ASL (Bandimere Speedway)
New - 07 Spec B/stg 2

"bloodstains - speed kills -fast cars - cheap thrills -rich girls - fine wine
i've lost my sense - i've lost control - i've lost my mind" Agent Orange
BSOD2600
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Post by BSOD2600 »

farfrumwork wrote:What do the 6spd mounts run$$?
RST-4101 STi Group N Gearbox Mount 5MT $75
RST-4102 STi Group N Gearbox Mount 6MT $75
http://www.rallispec.com/prod_mount.htm

'11 WRX Limited
'94 SS | 3" TBE, 07 TMIC, TD05H-16G, Revtronix Stage 2, Walbro -- Sold
'94 TW | R.I.P.
DLC
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Post by DLC »

farfrumwork wrote:
BTW, anyone want a 5psd Group N mount? <500mi total on it, $40 + shipping. It's been taking up spce in my garage for years now.

-Chad
I'll take it
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93forestpearl
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Post by 93forestpearl »

farfrumwork wrote: I liked the feel of the mount, so maybe I'll try it again with the 6spd version. I was going to compress the stock mount and fill it with the windshield seal material for a DIY fix, but I'd rather just swap a "lower" verison straight in.

The 6 speed mount does not work with the 5 speed. The mounting point on the transmission itself are different. THe crossmember side is the same.
→Dan

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BSOD2600
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Post by BSOD2600 »

Really? From that picture, they look about the same...

'11 WRX Limited
'94 SS | 3" TBE, 07 TMIC, TD05H-16G, Revtronix Stage 2, Walbro -- Sold
'94 TW | R.I.P.
brand
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Post by brand »

If someone wants to give it a try on their car, I'll buy it at full price for my STI if it doesn't end up working.
91 SS with a bunch of parts waiting on the shelf
94 SS with things and such
08 STI with stuff and junk
93forestpearl
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Post by 93forestpearl »

The mounting points for the tranny are different. I tried to line the holes up when I had it all apart two and a half years ago, and they were not the same. If they were the same, I would have noted it in my build thread at the time.

It takes two cuts and two welds to modify a downpipe for 1/2" of extra clearance.

Driveshaft, well that depends on what it is rubbing on. The BFH comes into effect.
→Dan

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farfrumwork
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Post by farfrumwork »

^^^^ Guess I'm back to the DIY modified stock mount plan then.

Thanks for the info Dan.
Old - '93 T-Leg - 14.693 @ 92.68 at 5800ft ASL (Bandimere Speedway)
New - 07 Spec B/stg 2

"bloodstains - speed kills -fast cars - cheap thrills -rich girls - fine wine
i've lost my sense - i've lost control - i've lost my mind" Agent Orange
BSOD2600
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Post by BSOD2600 »

Can anyone else confirm/deny the 6MT group n tranny mount won't fit our 5MT?

Do people just get the OEM 5MT tranny mount when theirs is going out and getting soft?

'11 WRX Limited
'94 SS | 3" TBE, 07 TMIC, TD05H-16G, Revtronix Stage 2, Walbro -- Sold
'94 TW | R.I.P.
BSOD2600
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Post by BSOD2600 »

Bump.

Thoughts? What do ya'll use when replacing the transmission mount? I've already replaced the engine mounts with group n. Have a helix DP and custom 3" exhaust.

There is quite a bit of [mis]information if they work or not:
* n2x4 stating using "STI group n"
* ultrasonic stating "transmission mount will fit if you have a 5MT and you get the 5MT Group-N mount. "
* ultrasonic (again) stating Group N transmission mount works for the 5MT
* farfrumwork stating Group N does NOT work and raises tranny/engine about .25"
* Threshld1 stating Group N worked, yet in his pics it appears the Group N is a little taller...
* kleinkid & simonasaur having clearance problems while BAC5.2 & -K- having none.

'11 WRX Limited
'94 SS | 3" TBE, 07 TMIC, TD05H-16G, Revtronix Stage 2, Walbro -- Sold
'94 TW | R.I.P.
kimokalihi
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Post by kimokalihi »

I will take a look probably tonight at my 6spd STI group N tranny mount. I bought it and installed it the other day but the tranny has not been installed into the car. Keep in mind this is a 97 JDM forester tranny so I don't know if there's any difference in mounting or not but they looked identical aside from the rubber material in the mounts.

I sure hope it fits though. I will find out for sure soon though.
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kimokalihi
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Post by kimokalihi »

Here's the segment from my build thread comparing the stock 5spd 97 forester tranny mount with the 6spd STI group N mount. Now that the old 91SS tranny is out I can compare all 3 and take pictures and measurements. I'll try to make the most accurate measurements I can.

I'll also try to compare the mounting points of the bolts.

From this picture it looks as though the heigh difference of the 6spd STI group N vs. 97 Forester stock mount is about 1/4" shorter than stock.

I also installed the Group N motor and tranny mounts. I reused the stock mounting plates because they have welded on heat shields and the Group N plates do not. Other than that, they are identical. The holes all line up the same in a straight line and they're the same thickness and everything.

The mounts are significantly stiffer. Particularly the tranny mount, that thing was so soft. I actually measured with a ruler that I was able to bend it about 1 and 3/4" with hand alone. I took a picture to demonstrate with my foot how much it bends. The Group N mount doesn't bend at all. Maybe 1/4" at the most.

The Group N 6speed tranny mount is the one I used. It's almost 1/4" shorter than the 97 Forester mount.

The motor mounts weren't much stiffer though.


Image
Image
Image
Image
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91 SS EJ20G Engine/Tranny/Diff Swap Build Thread Here
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kimokalihi
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Post by kimokalihi »

Actually after taking a second look at that picture on the bottom it looks as though the stock mount may have a wider bolt hole pattern than the Group N 6spd STI mount....

I dunno, I'll find out tonight.
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91 SS EJ20G Engine/Tranny/Diff Swap Build Thread Here
"Your testes are close to your bottom but you still play with them all the time." Jeremy Clarkson
93forestpearl
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Post by 93forestpearl »

The bracket to the tranny is what I'm looking at.
→Dan

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kimokalihi
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Post by kimokalihi »

Just got done putting my engine and tranny in. There's no exhaust so I can't comment on the clearance with the transmission being 1/4" lower but I'm sure I can work around that if it's a problem.

It does fit though. I have pictures which I'll upload when I'm done eating dinner. It went right in without a hitch.

Confirmed! 6spd Group N Engine AND tranny mounts fit just fine. The bolt patterns and bolt hole patterns are identical. The mounting surfaces are identical. The only things different about the two is the bushing is bigger and of harder material and the height difference with the 6spd Group N being 1/4" shorter.

Also, I checked my stock 91SS tranny mount and it has the same part number as the 97 forester mount so I didn't bother taking pictures of the 91SS since it's the same.
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91 SS EJ20G Engine/Tranny/Diff Swap Build Thread Here
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Post by kimokalihi »

Top - 97 Forester mount (Same part# as my 91SS mount)
Bottom - Group N STI 6spd Mount

Image




Group N mount is aproximately 1/4" shorter.

Image
Image
Image
Image




Bolts are spaced exactly the same distance apart in the same exact locations.

Image
Image




Here you can see it fits right on the crossmember.

Image




Installed in my 91SS with 97 Forester tranny/engine swap. No exhaust yet.
Image
Image
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91 SS EJ20G Engine/Tranny/Diff Swap Build Thread Here
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kimokalihi
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Post by kimokalihi »

I would say the 6spd mount is not 3.00 inch as pictured above. It's about 2 and 29/32 of an inch.
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91 SS EJ20G Engine/Tranny/Diff Swap Build Thread Here
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brand
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Post by brand »

Awesome, thanks for the pics and confirmation.
91 SS with a bunch of parts waiting on the shelf
94 SS with things and such
08 STI with stuff and junk
kimokalihi
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Post by kimokalihi »

No problem!
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91 SS EJ20G Engine/Tranny/Diff Swap Build Thread Here
"Your testes are close to your bottom but you still play with them all the time." Jeremy Clarkson
brand
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Post by brand »

Let us know how your clearance with the exhaust works out if you don't mind :)
91 SS with a bunch of parts waiting on the shelf
94 SS with things and such
08 STI with stuff and junk
BSOD2600
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Post by BSOD2600 »

Thanks for the detailed pics! Now I'm strongly considering getting that 6MT tranny mount...

'11 WRX Limited
'94 SS | 3" TBE, 07 TMIC, TD05H-16G, Revtronix Stage 2, Walbro -- Sold
'94 TW | R.I.P.
kimokalihi
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Post by kimokalihi »

I'll let you guys know for sure but I won't have my exhaust on for a while I imagine. I could probably throw my 3" downpipe on there if you'd like to see how it fits but I don't have the rest of the exhaust except the cat and muffler.

Is it the downpipe or the midpipe people were having trouble with?
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91 SS EJ20G Engine/Tranny/Diff Swap Build Thread Here
"Your testes are close to your bottom but you still play with them all the time." Jeremy Clarkson
BSOD2600
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Post by BSOD2600 »

Thought it was just the downpipe... well at least with my helix dp, that comes fairly close to the side of the tranny mounting stuff.

'11 WRX Limited
'94 SS | 3" TBE, 07 TMIC, TD05H-16G, Revtronix Stage 2, Walbro -- Sold
'94 TW | R.I.P.
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