Hi, I new to Chevy Duty. To make a long story short, I bought a 86 c10 (V8 5.0L 305) from a friend I beleveave it has a 700r4 in it, i had it for a week. I was driving on the freeway and it sliped going from 2nd to 3rd, tranny fluid was low real low, add some and it did the same thing it would drive in 1stand 2nd fine just not drive, and then it started leaking fluid pretty bad at the pan i beleave. Any how sorry for the log post, i was woundering which tranny is most likly in there the 700 and should i stick with that one or is there another i could use (like 350c?) with out any trouble. The truck has been sitting for almost a year now (also was sitting befor i got it) I saw this site and decide i wanted to get it running and fixed up. thank you for any help or sugestion any one might have!! Aaron @pcwiz@thepcwiz.org
RE: tranny help which do i have and At about 100k I was pulling an empty horse trailer up a hill and the engine reved like I had kicked it into neutral. Smoked third in my TH400. Once it slips like that usually it is shot. Auto rebuilds are not overly expensive. I had mine completly overhauled for $540, including a new torque converter and extra clutches and steels installed. The 700R4 is a 3 speed + overdrive, TH350 and TH400 are three speed. If you tow heavy loads with a 700R4 DO NOT USE OD! It will smoke 4th gear. These transmissions cannot handle the stress in OD, use D. Rebuild the 700R4 and use only trick-shift fluid, I cannot explain the difference it makes. Good luck. 79 C20 Bonanza 350/400 4bbl Q-Jet 3.73 14-Bolt Corp.
RE: tranny help which do i have and I almost forgot. A TH350 has a squarish pan with an angled corner, A TH400 has an illregular pan shape, and the 700R4 is square without a vaccuum modulator. Hope this helps. 79 C20 Bonanza 350/400 4bbl Q-Jet 3.73 14-Bolt Corp.
RE: tranny help which do i have and yes it thank it helps some what you described is what i think happened to me with it acting like it went into nuetral. Im pretty sure i have the 700 in there now it has 16 bolts on the pan if that means anything i think the 400 has 13. i was woundering if i could go with the 400 its cheaper from what i can tell. And no currently im not towing anything but i might be tower a boat but i will probably get a new truck for that. Thanks!!
RE: tranny help which do i have and Low fluid levels do cause heat build up, and excessive heat will kill any automatic transmission, quickly. You can put in a TH400, but you have to run a vaccuum line to operate the modulator valve. Also, be aware that the speedometer may not read correctly changing to a 400. The 400 is a great transmission but, considering gasoline prices these days, the 700R4 has come a long way in the aftermarket world of better parts.
RE: tranny help which do i have and [updated:LAST EDITED ON Oct-29-04 AT 10:47 PM (CST)]It sounds like you have the 700R4, since it has OD and 16 pan bolts. The pan should be square if it's a 700R4, and the other way to tell is by the location or absence of a modulator. " TH350 modulator is located at the back side of transmission case. TH400 modulator is located on the side of the transmission case, TH700R4 has no modulator." The above info is a quote in the LMCTruck catalogue.
