I am anal, probably way more anal than i need to be, and I have also been referred to as OCD when it comes to my cars or bike projects.
That being said, some of you may know I am in the middle of a 6 speed swap into my (automatic) 06 FXT. Actually I am still gathering parts and prepping things, and the actual swap will happen in the next couple of weeks.
Along the way, I have run into a few red flag moments.
One of those moments happened when I read something here about another member having problems with drive shaft angle when he did his swap.
Ultimately, it seems he had to fabricate a couple of spacers to gain more clearance and get the drive shaft at the proper angle to keep it from rubbing.
That thread is here: 6-speed transmission swap woes
When I started buying the parts I needed for my swap, I got an STi trans crossmember with the trans, and since my FXT is an automatic, I decided to play it safe, and buy a FXT (manual trans) crossmember. I work from the principle that says "it is better to be looking at it, than to be looking for it"
That being said, once I got the crossmembers powder coated and reassembled, I decided to take some measurements and try and spot the differences between the 2. Below are my findings:
First of all, the STi trans crossmember is much beefier, 2 of the 3 pieces are fully boxed sections, whereas the FXT crossmember is much less boxed out.
The next 2 pictures show that the FXT crossmember is much "deeper" at the point where the main transmission mount bolts to the crossmember.
It is approximately 1 inch deeper in this critical area which will actually allow the transmission to sit LOWER once everything is all bolted up. This probably explains why the other board member had to make a spacer to allow proper drive shaft clearance and angle when using the STi crossmember.
If you compare the image above to the image below, you can also see that the front part of the STi crossmember has a much more pronounced curve to it out towards the end that bolts up to the chassis. This will also place the transmission higher up into the tunnel than the FXT crossmember will, so if you combine the differences between the 2 portions of the crossmember, the total difference in mounting height is much more than 2 inches from what I can tell.
And below are separate pictures of each mount so you can see just how much more robust the STi crossmember is than the FXT crossmember.
Personally, I would much rather use the STi crossmember since I plan on eventually joining the 500 WHP FXT "club".
At the end of the day, once I get the transmission installed I will re-evaluate which mount is a better fit, and if need be, I will fabricate some spacers myself, or perhaps mix and match between the 2 crossmembers to come up with the strongest option, while still retaining proper drive shaft angle and clearance.
I will be using every Group-N bushing and mount available which will also help.
Particularly, the Group-N motor mounts will keep the twisting down to a minimum, BUT the Group-N tranny mount will transmit more energy to the crossmember, so that non boxed center section may flex a little bit which could be good, or bad.
Anyway, hope someone gets something out of this.
I sure did.
Edit to this post:
I am adding a picture to show the differences between the stock Forester XT (manual) transmission mount as compared to a new (6MT) Group-N transmission mount.
As you can see, there is an additional 1/2" difference in height between the 2. The FXT mount will place the tranny higher up in the tunnel without a doubt.
Ok so I got a call from GarageXTI and he needed some measurements to work out some drive shaft angle questions he had.
So, I bolted up the STi trans cradle with the requisite Group-N rear transmount and did the same with the FXT cradle and stock (rear) trans mount.
Then I set up some blocks on my damn near perfectly level garage floor which doubles as my surface plate-lol.
Using the same spacers (wood) and blocks for each cradle, I took a measurement to compare the height difference between the two trans mounts.
I made sure that the center section of the cradles were level, but more importantly I made sure that the contact points were sitting FLAT on the blocks and spacers the way they would when bolted up to the bottom of the chassis.
There is EXACTLY ONE INCH difference between the two.
The idea here is that if future swappers want to keep the Forester (front) crossmember in place ALONG WITH the spacers that go between the crossmember and chassis, then it may
be possible to space the transmission cradle by an inch and end up with proper drive shaft angles and NO clearance issues.
This will be confirmed by GarageXTi.
For now, here are the pictures.
FXT cradle set up:
FXT cradle measurement:
STI cradle set up:
STI cradle measurement:
So now we wait for GarageXTi to take his measurements and let us know if a spacer will do the trick for those that want to do the 6 speed swap, but NOT remove the subframe spacers.
This video explains why it is so important to get driveline angle set properly. Without the proper angle you WILL get NVH issues and premature u-joint failure without a doubt.