Hello everyone. Maybe I missed it as I searched the threads but has anyone done a TH400 to 700R4 swap? I've seen the swaps to 200-R4's but not the 700. Is there a reason for this? Is it due to the 60 torque rating behind a BBB? Also how about the 4L80E, how much work goes into putting an electronic tranny in a non electronic car? Worth it for the extra gear or not really? Thanks in advance.
Factory stock, I suspect that you will see those trans are rated for engines with outputs significantly less that 400 foot pounds of torque. Another solution is to keep your TH400 and install a gear vendors O.D. unit. Ask Larry. I recall the cost is 2K or more.
Oh yeah, I remember reading that post a year or so ago. I even looked them up. Thanks for reminding me of that option.
I'm curious to these replies too. The 200 R4 is equivalent to the TH350 I believe, but I do know they can be built plenty stout.
Yeah I was reading that too. It seems like the Gearvendors is a good option. Pricey but strong and smooth. I just looked at their website.
Besides the lower torque rating of the 7004R, that trans only comes in a Chevy bolt pattern, so you need an adapter. It also has a big drop between 1st and 2nd gear (3.06 to 1.62), not the best for performance even though the 3.06 is a nice low 1st gear. It would need to be beefed up to go behind a healthy BBB if you wanted to race the car. Yes, it is worth the extra gear if you do a decent amount of highway driving. The 4L80E needs a standalone controller (computer) to run it. I's a very nice transmission, basically a THM400 with an overdrive and lock up.
Thanks, I was wondering why you don't hear much about it and that's why. I use the Riv often and plan on using it way more as I fix it up so the extra gear will be nice. That Gearvendors is pricey but I like what I've read so far. That's a long way off though so we'll see what happens when it's time.
2004r is an easier swap but you do need to find the "right" builder . The 2004r bolts to the Buick engine and when swapping from th400 the cross member doesn't have to move. Both the 700r4 and 2004r will require a tv cable. This is NOT a kick down and MUST be installed and adjusted correctly or your trans wont go far . The 700r4 has a big sun shell that only takes about 5-600hp and you break it(even the hd ones). The 3-4 clutches are also a problem but there are ways to make em work. The 2004r has a "delicate" forward drum shaft that will take about 400hp but a lot will want to "dual feed" the direct clutches and that will pretty much require a billet shaft FWD drum as this dual feeding effectively doubles(or more) the fluid volume that is applying the direct clutches. The other deficiencies of the 700r4 are mentioned above.
