LG4/700R4 Problems!
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Joined: Jun 2001
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LG4/700R4 Problems!
Thanks for reading. I am "souping-up" my friends 87 Firebird LG4/700R4. Well I haven't started yet, but we are putting a 403/2004R in it. I built it to be a mild street motor. But some bad news, his tranny went yesterday, while he went out for a bit. I flushed it because the fluid was as black as the paint is. While he was driving it, the alternator belt snapped, and the Smog Pump belt went too.
Anyway, it will get going fine under light throttle, but under hard it revs to about 4, then engages. (You bet we were sideways!) It erratically shifts into second taking about a second and a half to complete the shift. Then after 3750 RPM, it free revs, and doesn't shift into 3rd or overdrive. This is his daily driver, so I need to fix it for him. It's top speed is 30 mph in 2nd gear. Could it be a miniscule problem? Please help.
If the tranny is gone, I have a TH-350 sitting in my garage for him. I know he will lose overdrive, but he has 2.73s anyway. Will this be a simple swap, what are the steps I need to follow to retrofit a TH-350 into a 87 car? I can't find any cheap 700R4s anyway. Will I have to move my crossmember? Will I have to modify my driveshaft? Can I swap out tailshafts from a 700R onto the TH350? I really need to get his car back on the road, he's paying me 3 grand to rod out his car! Help!
-ws6formula-
------------------
1989 Pontiac Formula WS6
69,000 miles.
------------------------
305 TBI, 4.10 gears, SLP Zexel/Torsen Limited Slip Differential, 700r4 Corvette Servo, LT4 Hot Cam/Valvesprings, GM Aluminum Driveshaft, 2700 RPM Stall, Edelbrock Performer RPM intake manifold, Turbocity TB. Ran on 6-19-2001 again: UPDATED: 14.1 @ 97.68 mph. Dyno'd Bone Stock @ 172.6 rwhp, 266 ft-lbs. of rw-torque.
Anyway, it will get going fine under light throttle, but under hard it revs to about 4, then engages. (You bet we were sideways!) It erratically shifts into second taking about a second and a half to complete the shift. Then after 3750 RPM, it free revs, and doesn't shift into 3rd or overdrive. This is his daily driver, so I need to fix it for him. It's top speed is 30 mph in 2nd gear. Could it be a miniscule problem? Please help.
If the tranny is gone, I have a TH-350 sitting in my garage for him. I know he will lose overdrive, but he has 2.73s anyway. Will this be a simple swap, what are the steps I need to follow to retrofit a TH-350 into a 87 car? I can't find any cheap 700R4s anyway. Will I have to move my crossmember? Will I have to modify my driveshaft? Can I swap out tailshafts from a 700R onto the TH350? I really need to get his car back on the road, he's paying me 3 grand to rod out his car! Help!
-ws6formula-
------------------
1989 Pontiac Formula WS6
69,000 miles.
------------------------
305 TBI, 4.10 gears, SLP Zexel/Torsen Limited Slip Differential, 700r4 Corvette Servo, LT4 Hot Cam/Valvesprings, GM Aluminum Driveshaft, 2700 RPM Stall, Edelbrock Performer RPM intake manifold, Turbocity TB. Ran on 6-19-2001 again: UPDATED: 14.1 @ 97.68 mph. Dyno'd Bone Stock @ 172.6 rwhp, 266 ft-lbs. of rw-torque.
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Joined: Jun 2001
Posts: 639
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From: FL
A long tailshaft 350 will work with no driveshaft mods, you will need to move the cross member 3" forward or bolt an extension on it if it's a temporary fix. But you'll need to buy an adapter to bolt the torque arm to, thats about $80 if I remember correctly, so it can get costly for a temp. fix.
The 700 and 350 output shafts and tail shaft housings do not interchange.
The 700 and 350 output shafts and tail shaft housings do not interchange.
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