3100 Swap

[DarkKnight]

Hey guys, Sorry to hear about GMF. We lost a lot of good info there... Anyhow when last I posted I was just starting a 2000 3100 & 4T45E swap into my first gen J-body. Although the financials have been a constant struggle, I have managed to perservere. The weather here has not exactly been favorable either, however I have the old motor and trans out, the entire front end suspension rebuilt, and the main trans mount finished. I will be construsting the other brackets for the the trans and installing it hopefully this week. I would get started today, but if it weren't for bad luck I wouldn't have any at all. A power line was knocked loose right above my driveway, (damn wind) and proceded to fry above me. I lost most of the power to my house, only one phase was taken out by the wire. (most homes are a 2 phase system). So I can't work on my car till the power company repairs the line. So I'll post some basic info I have come across during my transplant.

1) a 4T45e will fit (barely), though it is somewhat larger. I will try to explain below

THC125C

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4T45E

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So they are the exact same dimensions except for the increased length, the CV joints line up, but the pass. side will need to be shorter. The main trans mount uses a 4 bolt design (2 through the bell housing into the engine & 2 into the trans case) to bolt into the 125c, the 4t45e has a filler port and no bosses for the 2 that go into the case. So it requires major modification to work. However, I have implimented a design that I think will work, when it's all done I promise pics

If anyones interested, I will try to keep you posted. Also, has anyone else done a 3100 & 4t45 swap into a J before?

[Anonymous]

Wow talk about crappy luck lately! I'm sure nothing will stop you though, and it would be cool if you'd keep us posted on the progress

[DarkKnight]

Ok guys. So I was working with the transmision bracket and I was tightening the vise, I caught my right middle finger on the end of the steel (it was very sharp), and sliced myself open. Not only that, but 3 days later the lock failed on my new pocket knife, it went into my right thumb like a hot knife through butter. I have the feeling that someone up there doesn't want my to finish this project. After a few days of rest to let my hand heal (it started bleeding everytime I bumped it), I have resumed work on my car. I finished the bracket (tranny mount support brace), and I will be going to the parts store tonight to get a new rubber tranny mount. Hopefully the weather will hold out and I will have the transmission finished this weekend. I was thinking of using a 2001 GAGT trans mount to stabilize the unit latteraly. The GAGT steel mount attaches to the bottom radiatior support. What do you guys think?

[korbendallas68]

Do you need the mount? I can sell ya mine, its practically brand new! I actually have all of the mounts if ya wanna buyum.

[DarkKnight]

I have the transmission installed using the stock mount with a modified bracket, but the trans keeps twisting to the heavier side.

It twists like this.

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There is a dogbone on the 125C, but the 4t45 doesn't have a similar enough mount boss to use. I was thinking of using a mount from a GAGT that supports the trans laterally, but it would have to bolt to the radiator support. So, it might interfere with the either the radiator or the fan. Any ideas?