Just wondering if anyone has mounted their 4T65E-HD using the stock grand prix / regal mounting location on the side of the trans, instead of the two fiero locations.
It was a lot easier to fab a mount here so I went with it. The actual mount is a trans mount from a Ford.
[This message has been edited by MRose (edited 12-21-2011).]
IP: Logged
10:11 AM
PFF
System Bot
Alex4mula Member
Posts: 7405 From: Canton, MI US Registered: Dec 1999
That looks nice and easy but you will need a very good dog bone(s) to hold the rocking. I think thes GPs use two at the top. I really do not like dog bones at the top as they are a big distraction to the engine. But that's just me.
My intention is to install it exactly as it was in the GTP, single trans mount, single engine mount and two dog bones.
No reason to try and re-invent the wheel...There is a reason no one has used the method you are going to attempt...Save your self some time and add mounts to either side of the trans also..The dogbone you will be adding to the trans side of the motor with end up ripping the firewall up under all the torue....Save youself some time and install some trans mounts....
I use this mount setup on my personal cars, but only round out a total of 4 total cradle to engine/trans mounts.
Putting dogbone mounts on a fiero is really a mess, as there is no real good mounting place for them on both the fiero and the top of the motor. There are tons of very good solid points to bolt to on the lower half of the motor, and you can get away with "not so pretty" mounting systems down low as well.
Other perks:
Easier fab, no installing into the car, measuring, then removing.
Easier install/removal of the motor... Might be trivial sounding but honestly it is so easy to take the cradle out that even the little things add up quick.
Thanks for your input guys. Have any references to horror stories with dogbones mounted to the trunk wall?
I have seen a homemade mount rip the firewall up in just a month and this was behind a Duke on an auto. Just listen to what others are saying and follow suit...Add 2 more trans mounts and be done with it....
IP: Logged
07:53 PM
1fatcat Member
Posts: 1519 From: Zimmerman, Mn Registered: Dec 2010
I like your idea, but I do have to wonder about the strength of the dogbone mounts holding all the power. Another plus of using lower mounts would be that the center of gravity is lower.
I use this mount setup on my personal cars, but only round out a total of 4 total cradle to engine/trans
With the two mounts that I have, plus the two stock fiero transmission locations, could the dogbones be omitted? I think that's what you're saying you run on your car(s).
IP: Logged
08:57 PM
darkhorizon Member
Posts: 12279 From: Flint Michigan Registered: Jan 2006
I have never used a dogbone mount on an automatic car. Look at a Hbody car with a 3800 SC for inspiration on how to mount the trans in. They use 3 mounts from the factory, and a crazy "claw" mount to hold the block in. after you mount the trans with 3 mounts, the engine mount is just there to hold the motor up.
IP: Logged
09:25 PM
MRose Member
Posts: 267 From: west palm fl Registered: Nov 2011
Building a mount on the front (firewall) side should be pretty straightforward, the rear one might be a bit tricky. In lieu of the rear I could probably use 1 dogbone in the stock location.
I use a similar mount on newer autos that do not have the mounting bosses on the trunk side to work with but I also use the firewall side tranny mount along with it and a weaker trunk side mount to line things up. Dan
IP: Logged
04:53 PM
Dec 21st, 2011
MRose Member
Posts: 267 From: west palm fl Registered: Nov 2011
Anyone know the bolt size in the 4T65E for the two side mounts?
quote
Originally posted by fierofan25:
Do you have a part number for that mount. I was going to go the same thing with my N/A series 3. Thanks Lonnie
The one I'm using is from a '77 Ford Maverick (no idea how it got in the garage). Here's the Durajunk version: Durajunk Trans Mount
The two studs on the top are not an exact fit for the grand prix mount, i had to elongate the holes a bit. I would have used the stock grand prix mount but had already scrapped the cradle.
[This message has been edited by MRose (edited 12-21-2011).]
IP: Logged
10:49 AM
MRose Member
Posts: 267 From: west palm fl Registered: Nov 2011
I was able to make the motor mount the other day. I used an 84-87 motor mount, shifted forward as far as possible on the cradle. This was the only way the studs would come close to lining up with the grand prix U shaped motor mount bracket on the engine. I had to modify the 3800 side of the motor mount to clear the bump in the '88 cradle.
The engine is rocked forward quite a bit in this photo, there's actually a lot more clearance.
After that, we test fit it in the formula to check clearance of the oil filter adapter and the side transmission mount.
Too bad it's far from being in there permanently.
There's a lot going on in the shop
Hopefully the 3800SC formula will be faster than my LT1 '88 GTA.
This weekend I will be making the two side trans mounts and then starting on some other stuff.
[This message has been edited by MRose (edited 12-21-2011).]
IP: Logged
11:15 AM
phonedawgz Member
Posts: 17091 From: Green Bay, WI USA Registered: Dec 2009
When you dropped your 2.8 you took the harness off the engine IN THE CAR?
Wow - you are into pain. It is SO much easier to drop the harness with the engine, and then strip it off outside the car. Unplug C203, C500, the ECM and disconnect it from the power distribution posts.
3800 swap harness installation in the car isn't so bad however. Still given the choice I would still re-install it with the harness on the engine. I route my harness topside as much as possible to keep it away from the exhaust heat.
--- 56 or 57?
[This message has been edited by phonedawgz (edited 12-21-2011).]
IP: Logged
11:31 AM
MRose Member
Posts: 267 From: west palm fl Registered: Nov 2011
When you dropped your 2.8 you took the harness off the engine IN THE CAR?
Wow - you are into pain. It is SO much easier to drop the harness with the engine, and then strip it off outside the car. Unplug C203, C500, the ECM and disconnect it from the power distribution posts.
3800 swap harness installation in the car isn't so bad however. Still given the choice I would still re-install it with the harness on the engine. I route my harness topside as much as possible to keep it away from the exhaust heat.
I bought the car that way. Prev owner had started to replace the 2.8 with one from an 86 and thats how it was.
The front cross-member on the 'Prix is a great deal more rigid and designed to take the load of two "dogbones". I've seen first hand what mounting a "dogbone" towards the center of the firewall can do, the cross-member will separate from the strut towers. The "dogbone" on the right side of the cross-member only works because of the triangulation that's there. Pushing the firewall in isn't hard either.
I like your transmission mount, very creative. I would highly recommend an anti rotation anchor at the front of the transmission though. Possibly one by the engine too. Keep the axial loads on the cradle, it will handle them well, straightening a bent and separating trunk cross-member isn't an easy task.
IP: Logged
02:21 PM
MRose Member
Posts: 267 From: west palm fl Registered: Nov 2011
At this point I'm planning to add mounts in the original two locations, bringing me to four total mounts (3 trans, 1 engine) and then evaluating if I can come up with a mount for a dogbone in the original, triangulated location on the passenger side strut tower.
Also, you're the one who sells braided fuel lines, correct?
IP: Logged
02:42 PM
L67 Member
Posts: 1792 From: Winston Salem, NC Registered: Jun 2010
The tranny mount brackets from the 92 to 95 Trans Sport and Lumina vans that had the 4T60E 4 speed auto work quite nice with the Fiero lower mount pieces, on the firewall side it is a direct bolt on and the trunk side needs two new holes drilled into the cradle for mounting. Dan
The firewall side was as simple as some angle iron and a chevy trans mount.
The trunk side took some more work. I made a little platform for the mount to sit on, then made the associated bracket for the transmission. This one also uses a chevy trans mount.
Here's the front mount now that the motor is level.
All the trans mounts.
Seems to be mounted pretty firmly now.
IP: Logged
10:01 PM
Dec 31st, 2011
L67 Member
Posts: 1792 From: Winston Salem, NC Registered: Jun 2010
My only regret Is that its slightly crooked. It's perfectly level, but the passenger side axle is about 3/8" farther forward than the drivers side. Hardly noticable but enough to annoy the piss out of me.
Also it could be slightly lower. The transmission pan sits about 1/4" above the cradle.
IP: Logged
10:41 AM
Dennis LaGrua Member
Posts: 15526 From: Hillsborough, NJ U.S.A. Registered: May 2000
My only regret Is that its slightly crooked. It's perfectly level, but the passenger side axle is about 3/8" farther forward than the drivers side. Hardly noticable but enough to annoy the piss out of me.
Also it could be slightly lower. The transmission pan sits about 1/4" above the cradle.
The engine should really sit square and level to the cradle otherwise you could experience early axle failure. CV Axles don't like operating at a forward angle. They already have to cope with up/down movement and adding another angle of misalignment is not advisable.. Misalignment is one of the prime causes of early axle failure.Otherwise the job looks neat clean and well done.
------------------ " THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Flotech Afterburner Exhaust, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, HP Tuners VCM Suite. "THE COLUSSUS" 87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H " ON THE LOOSE WITHOUT THE JUICE "
Wow, great job mounting that thing! I love the simple yet strong mounts you got going there. I wouldn't worry about the axle...3/8" is not enough to be worried about it IMHO.
Can you share the part number/manufacturer of that chevy trans mount? I would like to use it for my swap as well.
IP: Logged
11:37 AM
MRose Member
Posts: 267 From: west palm fl Registered: Nov 2011
