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3500 swap question

Posted: Mon Oct 14, 2013 10:08 am
by Tylerlp
I have everything installed in my 95 beretta when it comes to a 3500 swap, but the only thing i have ran into an issue with is the engine to trans bracket that connects the extension housing of the trans to the "back" of the engine on the passenger side. What have you all done great 3500 swappers to make a bracket for this. and in case it wasnt obvious i have a 4t60e auto. thanks in advance!

Re: 3500 swap question

Posted: Mon Oct 14, 2013 11:14 am
by 3X00-Modified
Build one... You have to re-design it to fit to the block bosses... that's about all you can do.

Re: 3500 swap question

Posted: Mon Oct 14, 2013 11:38 am
by Barry
When I bought my 3500 it came with a bracket there for a different trans. I was able to cut it off where it bolts to the block, then cut the trans bracket for your 4l60 so it mates up to it, then weld them together. Add a gusset if you like.

I did it with my manual but it's the same concept. You reall don't even need the 3500 bracket. Just bolt a flat plate to the block and weld your stock mount to wherever that plate lands.

Re: 3500 swap question

Posted: Mon Oct 14, 2013 5:45 pm
by Rettax3
How essential is this bracket on the auto? Has anyone left it off and had a problem with the case cracking or flexing? The 3T40, and even more so the 4T60E, seems really strong along that area, it is hard to imagine it having problems...

Re: 3500 swap question

Posted: Mon Oct 14, 2013 8:21 pm
by Asylum
Just left of off on my 3t40.

Jettisoned the front sway bar too.

Car never broke anything in that area, and it was beaten on pretty good.

In fact the only thing it ever broke was a 120,000 mile axle and that was my fault.

Don't sweat it.

Re: 3500 swap question

Posted: Tue Oct 15, 2013 9:00 am
by 3X00-Modified
Eh, I don't know... I know you never broke anything in the time frame you had it but I really feel that after a long duration of street driving the trans case will flex enough to start cracking somewhere. It's not exactly the same but the manual mounts will crack the aluminum bracket so you KNOW there is a form a flex happening. I'd do what Barry said... just get a flat plate in that area and adapt it to the old bracket. Simple fix if you have the ability to weld something.

Re: 3500 swap question

Posted: Tue Oct 15, 2013 10:52 am
by SummitBalt08
Am I gathering that a Manual transmission needs a bracket also?

Re: 3500 swap question

Posted: Tue Oct 15, 2013 10:53 am
by Asylum
Well it may be true that I didn't drive it "a lot" on the street as a daily thing, and Barry seems to have the easy fix, I think mine would have shown some evidence of a problem.
Had pretty aggressive gearing, great traction and a lot of stress, but again that was a 3t40.
My trans was out of the car two or three times a year and I'm sure Billy would have noticed something.
But GM did put it there for a reason.

Re: 3500 swap question

Posted: Tue Oct 15, 2013 10:58 am
by Asylum
SummitBalt08 wrote:Am I gathering that a Manual transmission needs a bracket also?
I think on a manual it might be more important, especially if you are going to beat on it.

Re: 3500 swap question

Posted: Tue Oct 15, 2013 12:10 pm
by 3X00-Modified
SummitBalt08 wrote:Am I gathering that a Manual transmission needs a bracket also?
Most definitely... I have no idea what the 6 speed extension housing looks like in that area but the old 282 aluminum extension housing was really easy to break, Ask Mike pride he blew up the one on Cliff's car... the quad version of the extension shaft was much better and is what I put on Roberts combo. You can see that in the build thread I did.

Re: 3500 swap question

Posted: Tue Oct 15, 2013 2:25 pm
by Rettax3
Asylum wrote:But GM did put it there for a reason.
That is about what I was thinking -GM doesn't waste a lot of materials on unnecessary bracing, but I still have a hard time seeing where that one is required. Either way, probably nothing really wrong with however you do it -but it isn't quite so simple for someone who doesn't have access to welding equipment.
3X00-Modified wrote:
SummitBalt08 wrote:Am I gathering that a Manual transmission needs a bracket also?
Most definitely... I have no idea what the 6 speed extension housing looks like in that area but the old 282 aluminum extension housing was really easy to break, Ask Mike pride he blew up the one on Cliff's car... the quad version of the extension shaft was much better and is what I put on Roberts combo. You can see that in the build thread I did.
The 282 five-speed had two major variations -most I've seen had an aluminum extension housing that bolted onto the right side of the transmission and covered the intermediate shaft running to the right-side drive axle. It housed the oil-seal at the end, and had an aluminum bracket bolted to it that attached to the engine-block, like the autos have. That aluminum bracket was very thin, and not built well at all. It wouldn't take much to start cracking one, but as Jon said, it is indicative of flexing or movement caused by the CV moving, and possibly from torque reactions from the drive-line. The housing is likewise small (maybe two inches in diameter), and has no other support until attaching to the transaxle about twenty inches or so away from the inner end of the CV axle.

The other version of the 282, which was originally on my '90 3.1 'Retta, does not have the aluminum housing at all. Instead, an oil-seal is placed into the transaxle case, where the extension-housing bolts on the other versions, and the drive axle has a support-bearing at the end by the inner CV joint that has a thick steel bracket that attaches to the engine to keep everything from wobbling around. It is a much tougher piece than the aluminum bracket.

The six-speed F40 uses something very similar to this design, with an intermediate shaft (or 'jack shaft') that plugs into the transaxle at the differential, then runs behind the engine and is supported by a bracket and bearing at the far right end, where a short CV axle plugs into it.

Re: 3500 swap question

Posted: Tue Oct 15, 2013 7:41 pm
by 1988GTU
for the later design engine mounts, it would be fatuous to not at least try and make that bracket. For the L bodies with the rear engine mount AND that bracket... I could understand deep sixing it.

Re: 3500 swap question

Posted: Tue Oct 15, 2013 8:38 pm
by Rettax3
1988GTU wrote:for the later design engine mounts, it would be fatuous to not at least try and make that bracket. For the L bodies with the rear engine mount AND that bracket... I could understand deep sixing it.
I'm definitely not arguing against you here, just to clarify, but why do you think it would matter to the transmission brace if the engine had a rear mount or not? That brace's sole purpose is to support the right side of the transaxle to keep it from flexing from either torque side-loads generated by force applied through the CV joints/drive axle and radial (relative to the axle-shaft) loads caused by steering and suspension movements transmitting forces through the axle... I don't see where the older-style mounts need this brace any more or less than newer-style mounts... What is the reasoning behind this statement?

Re: 3500 swap question

Posted: Tue Oct 15, 2013 11:27 pm
by Cliff8928
Probably because with the older style engine mounts, everything uses the same 2 bolts. For what it's worth, It took a TON to break that aluminum bracket, which is now replaced with a steel version.

Re: 3500 swap question

Posted: Tue Oct 15, 2013 11:53 pm
by Rettax3
Cliff8928 wrote:For what it's worth, It took a TON to break that aluminum bracket, which is now replaced with a steel version.
Breakage wise, the aluminum would be fine. What kills them is back-and-forth flexing over time -they are too thin and bent too sharply, they just don't last over the years very well. They aren't stiff enough to keep from flexing either. I don't think I've found a single one that wasn't cracked.