I have never done any trany work but I like to do all my own work on my Riv. Any one can pay someone to build an old car for them the fun is in doing it yourself. Anyway I need to rebuild my th-400 its not slipping but its leaking a bit out the front seal or the torque converter. Any tips for someone who is attempting this for the firt time. A friend of mine who owns the local part sorce told me if I can build an engine I can build a trany.
I have not done it yet, but I will be soon. Make sure you get a good service manual.:Smarty: Your problem does sound like a bad front seal. You do have to pull the tranny out, or the engine, but is otherwise a pretty easy fix.:TU:
Its not hard, buy a book or two and read up on it(Ron Sessions book is the one I used). This link http://www.v8buick.com/showthread.php?t=69003&highlight=transmission+rebuild has some good info also. It does require a few special tools, but if you're creative you can get by. Good luck
a couple things you will need to know before you do a tranny. theres always a reason why something failed. in the case of your seal it could be a couple things. maybe the bushing wiped out so the torque converter floped around and fluid leaked past the seal (seen it happen) what caused it was the torque went bad and caused metal to go into the bushing and shaved part of it off, wore a groove in the converter which made it shift over past the seal so it leaked. another possibility may be the vent is clogged so the tranny has too much pressure in it so it blew the seal out. another one is the seal could have been old and just fell apart. could be more things but this is just a couple. make sure you check everything to make sure it is good and works. Haynes makes a decent tranny overhaul manual that covers the 2004r, 350, 400, and 700r4. get a good overhaul kit. i use transtar. they have great kits for great prices. the kits come with borg warner clutches, transtec gaskets and seals, and clevete bushings. heres the website so you can find one near you http://www.transtar1.com/default.asp also i would put a transgo shift improver kit in it too. they are cheap and they are just fine for the street. or if you want a racing shift kit in it you can do that instead but if not then the transgo kit will be just fine. good luck and if you have any questions let us know:beers2:
I agree with 1BadWagon about the front pump bushing. If it is worn out, check you flexplate to see if it is bent or cracked, which is the #1 cause of front pump bushing failure. Also, the Transtar kits are excellent. I bought a master kit for a 400 turbo three years ago and it cost around $80.00. The most important thing you will need in rebuilding a stock turbo 400 is a lot of patience. Things can get frustrating at times and you will want to take your time to assemble the transmission correctly. You also need to work on the transmission in a very clean environment. Dirt or grit can destroy an automatic very quickly. How I would advise you to approach the rebuild is to first clean the case as much as you can before you start the disassembly process to keep dirt away form the internal components as you disassemble the transmission. You will not find any of this advise in a rebuild manual. As you disassemble the transmission, rebuild every sub component as they are removed from the transmission. If you take it all apart at once and put all of the parts in a pile, you will immediately get lost and not know how to reassemble the transmission. As you rebuild the direct and intermediate clutch drums, make sure to use vasoline to "stick" the thrust washer back to the drums so you know here they go, and so they cannot fall off leaving you to wonder where they belong. If the transmission shifted OK and did not slip, you can assume (although you should check line pressure) that the front pump and the valve body are OK. If this is the case and the above mentioned is OK, I would not advise anyone doing this for the first time to remove the valves from the front pump or the valve body, since you risk raising a burr on these parts during removal which can cause them to stick later on and cause SERIOUS issues later on warranting another rebuild. You will also need the following tools and supplies: -A good set of internal and external snap rings. -A can of WD-40 to wash out the valve body. i like WD-40 because it does not dry out the valve body and cause any of the valves to stick. -A good manual. The Ron Sessions book is good. -Some .004 shim stock (you can use aluminum soda cans for this since the aluminum is only .004 thick). -Vasoline for seals and sealing ring assembly. -A couple of cans of carb cleaner for washing parts. -You will have to fabricate a tool to remove the spring plate (lack of a better word) from the clutch drums. -New transmission fluid to soak the new clutch plates. If I have omitted anything, maybe 1BadWagon can chime in to add anything to this that I have forgotten. if you do not have the patience for this then I would recommend fixing only the front seal and/or bushing if the transmission otherwise functions OK. Hope this helps. Ken
couple small little tidbits i can think of are get a couple cans of engine brite or some similar engine degreaser and soak the empty case. then use a power washer to rinse the case out. make sure you get all the grease off. then blow dry it with compressed air. make sure you dry every part of that case. if you dont have a power washer then sneak it over to one of those coin wash places. make sure you clean all the parts really good. you want to make sure you get all the dirt and grime out of the parts so it doesnt ruin the fresh tranny MAKE SURE you change the torque converter. they are cheap from transtar (59$) its not worth rebuilding the tranny and putting a used converter full of old tranny fluid and metal. flush the lines and cooler out because again, you dont want old fluid and metal in the tranny. if you really want to be slick then you can run inline filters in addition to the one in the pan. that way you can keep the fluid really clean and change the filters every few thousand miles. you can get ones that are kinda of like fuel filters or there are some that use an adapter for an engine oil filter. good luck and if i can think of anything else then i will post it:beers2:
another thing i just remembered is do a runout check on the crankshaft where the flexplate bolts to it. you will need a dial inticator. another thing to check is the pilot in the crank. do a visual and it would also be a good idea to do a runout check on it too and for that you will need a sideways dial indicator.:beer
Thanks that's all great advice I was planning on putting in a mild stall and shift kit. When I rebuilt the engine the cam specs recommend it. How high of a stall should I use the car has and may never see a track and is geared fast. Also was told a smaller diameter torque converter may work better.
