Has anyone swapped their TH400 for a 4L60 in their Buick? Looking to do so with my 68 Riv and seeking good ideas that lead to an OD solution
Since you are going for just a 4L60 which is TH700R4 I would do that,,,, No stinking electronic box Major BIG Bucks with all the parts needed..... I would try to find a later 80s 700... the later 90s were redesigned for softer shifting..
Ken at Everyday performance sell the TV kit for the QJ carb... https://www.everyday-performance.com/tv_arm.htm
Its very hands on, but a $360 Microsquirt controller, wiring harness, some plug connectors, and a rudimentary throttle linkage mount TPS sensor could run a 4l60e for ~$450 or less depending how resourceful you are. I've had one paired to an EFI system in my Firebird since 2018.
Thinking your biggest issue will be the space you have to work with under the Riv. That X frame may give you problems
Is there room for the Gear Vendors Overdrive, or a 4L80E in a 68 Riviera? Those are the only OD options I would consider these days.
^^^^^Good point. ^^^^^^ I've seen lots of Impala X frame cars with 700R4s... Then again I don't know the difference between a X Frame's on wildcat let alone a River.
I know. Measure 50 times, cut once. It would be nice to know if anyone has even attempted it, or attempted any similar mod.
I dont know of anyone that did a OD trans with the stock configuration or even a gear vendors for that matter. John Lyons put a manual 5 speed in his carbon fiber pro touring 68. I know he had to modify the frame and probably the floor boards. If it would work I'd be down with making that change as well
Has anyone swapped their TH400 for a 4L60 in their Buick? -> yes atleast one member has a 700 in a Riv. Looking to do so with my 68 Riv and seeking good ideas that lead to an OD solution -> Gear vendor unit will not fit and will require significant modification regardless of where placement is done. My 70 has a 4L80e. It is a tight fit but works. Each car is slightly different, I probably got away with it because all my body mounts were newer and stiffer. My car is not a GS, but I do have 3.42:1 posi in the rear. But honestly though, as the years gone by, I've become indifferent to it and even considered reversing back to the 400. I get more enjoyment out of clicking through gears manually than the actual benefit of OD. My GS convert doesn't have OD but does have a 3.42 rear and the rarity that I drive on the highway with either car just reinforces the point where you need to consider enjoyment working on it or driving it. Fuel saving is marginal/non existent for me, I could do some more AFR fine tuning at cruise...but nah. If aiming for the least work 200-4R - but cost is probably just as expensive as other transmissions. The right answer is 4L80/4L80e/4L85e Equivalency: TH350 = 4L60 - all variations/700R4 TH400 = 4L80/4L80e/4L85e People have had reasonable reliability with the lesser transmissions like the 200-4R or 4L60/700. 200-4R appears to be the preference over 700 for many reasons including gear ratio spread and the fact that 200s built properly were used in Grand Nationals a lighter car though. In the https://www.v8buick.com/index.php?threads/got-jiggy-with-it-4l80e-behind-455-bbb.302742/ see post 21 are my links to install. I looked at the links, they didnt work for me, I spent some time collecting info to guide a riv install....maybe the links will work for you. Post 21: " Ton of info. Here are just a hand full of links: Post #2 has a parts list. http://www.v8buick.com/showthread.php?297332-4L80e-Behind-a-455-Info-needed Post #44 has pic of install in a Riviera. See the .pdf attachment in that post. http://www.v8buick.com/showthread.php?157013-nother-1970-Riviera-owner/page2&highlight='nother+70 Post #7 see attachment as well: http://www.v8buick.com/showthread.php?256412-final-trans-choice&highlight=4L80e https://www.v8buick.com/index.php?t...or-other-late-model-trans-diy-tcm-tcu.304953/ "
I just went through the 2004R conversion process (among a million other things on my car) and it was well worth it. In my case I was lucky enough to score a BQ valve body from an 84 Turbo Regal for about $200ish 5 or so years ago. Sat on it while I did a bunch of restoration/upgrades. I had no idea if it would work and took a pretty big gamble doing a shift kit and deep pan before I installed it. The hardest part for me was building a custom crossmember, but if you're not boxing your frame you shouldn't have to do this (are X frames open channel?) I'm not sure about the X frame, but on the A-body you can conveniently reuse the stock crossmember and just slide it back (again if not modding the frame). Since you're coming from TH400 I'm guessing you'll have to shorten the driveshaft? I recently got the lockup working with the Bowler lockup kit, works well despite some troubleshooting of the cheap brake switch they included. I reused the TV cable from the Turbo Regal and the new Holley carbs have a provision for the 2004R built into the throttle shaft (they claim) so that's what I'm using. It shifts pretty hard and the Bowler kit delays the 4th gear lockup by 10 seconds and disables it under braking. I'm very happy with it so far!
This is a kinda old thread if you still need some info id be glad to share. I will say 1980s were the learning yrs fir gm.the 90s they started getting it right. If you want one to survive you need to beef it up and build it right. Im totally happy with my setup. With 3.08 rear gear in od 70 mph with lock up off about 2000 rpm. Lookup is about 500 rpm less. First gear moves you very quick, 2 gear is a wider spread than with the 200 not ideal for racing but its barely noticable with the torque we got. A long list of need to do's. Crossmember does not have to be moved at least.
