View Full Version : 350V8 takes out 700R4??

12-12-2009, 08:33 AM
Yesterday morning my lower tranny line sprung a leak. So a couple hours on the ice in front of Napa I fix it. Then my 350V8 starts dying. I get home and I take the filter out of the carb and put in a in-line filter, and now my 350 just has gobs of power[36] [36] .... I took it out on the rd and pined it in 4wd since the rd was so icy and the 4 barrels just kicked in live freakin' wow!!! I take the truck back in the garage. Put a water heater im my lower rad hose and then take it for another rip and like I'm going hardly no where and the engines just revving out in every gear and reverse. I manage to limp it back in the driveway. Now my question is... I noticed my 700R4 tranny slipping between gear changes this past month now no go!!! Plus I hear this dull knocking noise up in the tranny pan so I'm thinking the tranny pump is gone or what?? Its got lots of fluid! So I have a th350 mated to another np208 so I guess its time to do a re&re! I use this truck for snow plowing so I guess the th350 would be better anyways! So any feedback?? Can a regular guy like me fix the 700R4?? I got a slew of driveshafts around and I know I may have to drill some holes for the x-member, etc.:confused0006:


12-12-2009, 10:04 AM
The 700R4 (especially the earlier ones, pre 88 IIRC) were one of the weakest autos that GM put out. The only good points they have is a lower first gear ratio than the other autos and an overdrive.

They are a non electronic trans and it is possible to overhaul one in the garage with hand tools, there is some special tools that would make the job easier but I helped a friend assemble his without any specialty stuff (he was the tech I was just an extra set of hands)

If you have a TH350 and tcase combo I would use that over the 700R4 unless you are dead set on having the overdrive. The TH350 is a WAY more reliable trans than the 700R4.

I have had and have friends that have had 700R4s in all shapes and sizes of vehicles and every one has had issues.

12-12-2009, 05:28 PM
Thanks. Just tried moving the truck and will only kinda move in 4 low. So its a plow firewood truck so I'll put in my th350. Keep the 700R4 for a disection winter project![cheers]

12-12-2009, 07:06 PM
If ur gonna use it for work a Turbo 400 would take more abuse

12-13-2009, 05:34 AM
I don't think I have a turbo 400 but I'll check... lower first gear right! However does a turbo 400 have the cast flywheel cover and struts to the engine mounts? I brought the replacement th350 into the garage last night but I guess I'll crawl under my other parts truck (in the snow:o ) and see what it has... I think it has a np205 too with slip joint driveshafts...[36]