Hi, I know some people say no stupid questions.....but is there a right and wrong way for tranny cooler lines for transmission to rad ? As is there an inlet/outlet for tranny and for rad ? Car is a 70 GS 455. In the Manual it shows top brass fitting on TH400 goes to top of rad and bottom brass fitting to bottom of rad. Well my new Inline Tube lines for TH400 are opposite to Manual having them run quite parallel ( as parallel as 2 bent lines can be) and if I switch them by removing clips they are way off as per routing nicely. They thread in nice the way they cam but bottom tranny point goes to top of rad and vice versa. Also my bottom lines meets up a rad perfect the top one is approx. 3-4" higher then female fitting point on rad. I measured old line and distance between upper/lower 90 deg bends is about 10 1/4" and the new one is very close to that measurement. Just a bit perplexed.... Any help would be appreciated. Thanx Dave
It sounds like you don't have the correct lines for the 455/TH400 setup. You may have a setup for a 350/TH350. Call inline tube and re-check what you got. Can I assume you are installing the tubes with the engine and transmission already in the car? And that the clip you are refering to is the one on the RH frame rail that keeps the lines from interfearing with other things in the engine compartment? IIRC, the top line coming out of the transmission is the line on top of the radiator and the bottom line coming out of the transmission is the line on the bottom of the radiator. And this would imply that the fluid flows from the bottom line out of the transmission to the bottom of the radiator then up the internal cooler in the radiator to the top line and back to the transmission. I recall that the radiator is stamped with "in" and "out" on the ports. I'm probably forgetting something but....
Im not so sure it matters either. When you think about it, your just completing a "loop". My aftermarket cooler is mounted so both ports are facing down.
I don't know if it matters either but I have never worried about it. So far no fried trannies. Bob H.
I did this when having a shiftkit installed in my TH350. I asked my trans guy a similar question (hes been in the business for almost 30 years) and his reply was it doesnt matter. either line from the tranny can go to either fitting in the rad.
I looked in the TH400 book by Ron Sessions and confirmed that the design is for the line out of the transmission to cooler is the lower line and the uppper line is the return to the transmission from the cooler. It is also referenced in the Wikipedia entry on the Turbo-hydromatic transmission.
Since the line connections are one above the other it wouldn't make sense for them to cross. It seems logical that the bottom line on the transmission would go to the bottom radiator fitting and likewise with the top. Not sure if there is any other reason.o No: Bob H.
It matters if you are using an auxiliary cooler since you want the auxiliary cooler spliced into the return to the transmission. On a Turbo 400 (and most other GM automatic's) the return is the top line. On a 200-4R the return is the bottom line.
Well I log on and you guys never cease to amaze me. I was hoping for 1 or 2 replies and all this in 1 day! Thanks guys ! Anyway, I ordered the Inline Tube # BKT6802 (5/16" Transmission lines for TH400 ) so not sure if that is what I have/got. I am taking some pixs and will post Wednesday. The lies have a 2 clips to hold them together and I removed those and even tried each line. They like being bottom tranny-top rad and top tranny to bottom rad for a really nice fit. So it seems this doesn't matter but my top line to rad still seems kinda incorrect. Is this an original rad in car? who knows. Lines seem to be original to car by bends ...but again who knows. Has anybody ordered the above kit from inline and have it on their car now that can tell if top goes to top rad and etc? Also what is distance between point for lines on your GS 455 rad ? I am going to pull my old lines out of scrap area and do a comparison Wednesday night. Again guys ..Thanks so much. Dave
I took my rad into rad shop to get tank with inlets 12 1/2" apart.The rad at first said was for small block TH350 car and the larger tank /cooler is for big block TH400. The rad itself is in very good condition and had no holes issues when pressure tested. But they tell me cannot get through any supplier a tank for one side with larger tranny cooler. They say nothing they can do for me. So should I post in parts wanted section? Really hate to buy a new rad when this one is so good other than cooler lines do not match up. Dave
Looking forward to some pics and any other info. I may be replacing my lines soon. Thanks Bert Roll Tide!