Odd stalling problem

[travisr1988]

So, my truck runs great now, most of the time anyways, but after long drives (20 miles) it stalls in reverse. Its a 1977, 355 with a quadrajet, mild cam, th350. Vacuum is healthy (last reading was above 19") and carb is tuned good now, timing is set at 8° initial, 14° with vacuum advance hooked up. As stated the truck runs great, seems to have good power, idles at about 600rpm, only other issue is I can feel a little chatter at light take off, which I believe is the rusty brakes. It only stalls in reverse and only after a longer trip (highway). And once it stumbles or stalls on reverse it will stumble in drive but not stall. Any ideas on what could cause this?

[zieg85]

Try raising the idle some.  If your torque converter is not slipping like it used to that may be the issue.  When you put it in gear does it hit hard and want to lunge?  I had a 700R4 that did that, just sold it like that as I was parting it out anyway... Just a thought.

[travisr1988]

When I put it on gear it behaves normally except when it gives me the stalling issue. It did it when the idle was at 800 as well, even when the lowest idle I could get was 800. And as for idle, it idles at around 600 most of the time, sometimes it gets low, sometimes it gets high.

[travisr1988]

Now that you mentioned torque converter, my transmission was leaking pretty bad up until the other day (tube was loosr) and I do hear a faint click when put in gear (always assumed it was from the linkage, and it seemed to rev higher at times yesterday. Like it was running say 1600rpm at 45mph but later that day it seemed to be at 2200rpm at 45mph (no tach yet so by ear) which I assumed was just me. As for idle it is verified, my timing light tells me rpm.

[travisr1988]

Well guys, I brought the issue up with my dad, and it seems my transmission is going out, it now makes a clunk downshifting into 1st at lights, idles up, revs more at cruise, makes a whining noise (didn't notice until I drobe between 2 walls) and the shutter at take off is back, it also doesn't like to shift into 2nd in parking lots until 20mph, unless I give it more gas. Anyone know where I can get a trans cheap and reliable? Would prefer 700r4 but another th350 will suffice. Thank you all in advance and thank you zieg for your guidance.

[Irish_Alley]

with a new/used trans a direct swap will be easy. but a 700r4 should save you a couple mpgs but are prone to failure if not setup right (t.v. cable) also take note on the tail shaft of the th350 theres 3 different lengths (6,9 and 12") any will work but your old driveshaft might not be the right length. is you get one from a truck thats similar (i.e. long bed or standard) then you can take the driveshaft and be good. i think for 500-700

now you can get a buy a blown 700r4 and get it rebuilt and be good as long as you get the carb bracket for the tv cable (if you dont have) maybe crossmember and driveshaft and this might set you back 1-1.5k or you could just get a 700r4 for about 700 and get the parts and not have it rebuilt then take a chance on it

[Stewart G Griffin]

Where do you have your vacuum advance hooked up?   Ported or manifold?

[travisr1988]

vacuum advance is currently on manifold, the carb I have does not have any ported, all are pulling vacuum at idle. And seeing as a 700r4 with 3.42s drops the cruise speed too low for my cam it looks like a th350 is my best bet, and easier on my empty wallet too. Anyways, since the stalling is only in reverse it seems very odd, the fact that it only occurs after a highway drive of decent distance it seems the carb may be the culprit. BTW, timing has been at anywhere from 0* to 16* at idle and still had the same issue with stalling under the same conditions.