I'm looking to have my transmission gone back through. Right now it's the numbers matching turbo 400 with a shift kit and 2500 stall. The trans has been giving me issues for awhile so I want it to be gone through again. If I do rebuild what I have is there any type of parts or kits that work better for a buick? Right now the engine is a mildly built 400. I'm debating if the stall also should be replaced since I'd prefer to start fresh. Any recommendations on specific brands or parts that seem to hold up better? I'm right around 400hp with 3:64. Im also considering if I should do an overdrive transmission instead. I'm not sure which would be better suited a 200r4 or 700r4? If either of those would work what else's would need to be changed to make the switch over? thanks mike
There is a ton of information on transmission options here on V8, just do a search for what you are interested in. http://www.v8buick.com/showthread.p...ark-shoppinglist&highlight=2004r+transmission http://www.v8buick.com/showthread.php?291362-2004R-vs-700R4&highlight=2004r+transmission http://www.v8buick.com/showthread.p...-trans-Questions&highlight=2004r+transmission http://www.v8buick.com/showthread.php?176591-TH350-200R4-swap-summary&highlight= http://www.v8buick.com/showthread.p...s-2004-r-Install&highlight=2004r+transmission Plenty more. Buick transmissions aren't any different than any transmission behind other GM engines. Different bell housing bolt pattern, and different valve body calibrations are about it. There is better clutch materials and other options any re builder could probably explain to you. Shift kit is always a good idea. As far as stall speed goes, you get what you pay for. There is no such thing as a 2500 stall converter. The exact same converter will stall at different RPM depending on engine torque, car weight, and gearing. Off the shelf torque converters will have a stall speed range, and that may also be misleading. The torque converter is probably the most important factor determining your car drive ability. The best option is to have one built for your exact combination. If you have the right converter, you shouldn't be able to tell until you lean into it. There really is no reason to put a non stock converter in unless the cam you are using needs it. Lots of mild combinations do better with a stock converter. Put 2004R into the search, plenty of threads on that transmission. The 7004R is doable, but it doesn't have a BOP bell housing bolt pattern so you need an adapter. The 7004R also has a very low 1st gear, I believe 3.06, but then there is 2nd gear at 1.62, so big RPM drop, not the best for performance. Either transmission will need to be beefed up to varying degrees to deal with big block torque and heavy car weight. The third option is the way I went. Gear Vendors Overdrive. Rated for 1200 HP, you'll never break it. It is an add on to any transmission. You'll need to shorten your drive shaft. Yes, it is expensive, but so is beefing up the 200/700R4 and buying a converter for them, the 350/400 converters will not work in the overdrive transmissions.. https://www.gearvendors.com/hrgm3s.html
A little math might be in order to determine how far you drive and how much a conversion will cost. A weekend car that might see 200 miles a month would probably never recover the cost of swapping in an over drive or gearvendors unit. The cool guy factor might override the cost. if I were to swap, I'd do a 2004r because it bolts to the back of the block, and you can use the crossmember you have. With the 2004r or the 700r4 you will need a different yoke on the driveshaft(27 spline as opposed to the 32 spline for the th400 I believe). Either of these lighter duty transmissions will need upgrades and a competent builder to survive the torque of the 400 engine. You might look into a switch pitch setup for the th400. Not so common but with the right stall speeds can be an excellent way to get the car doing good launches and cruising the hiways. Any of these will require a competent builder. Check them out to be sure they can accomplish your goals. The local guy who builds the "race" transmissions might not know or be able to deliver what you want. Get some references and check them out.
