Author Topic: Which Transmission???  (Read 4340 times)

Offline 83HighSierra

  • Newbie
  • Posts: 96
Which Transmission???
« on: July 15, 2007, 06:44:40 pm »
Im trying to figure out what kinda transmission i got. Ive had one guy say i had a 700r4 but to me it looks like a th350. Can yall tell which one it is?




Offline dumbucket1

  • Too Many Trucks
  • Junior Member
  • ***
  • Posts: 597
  • Coal Hauler
Re: Which Transmission???
« Reply #1 on: July 15, 2007, 07:08:02 pm »
the long tailshaft and the vacuum modulator give it away as a th350 but I'm pretty sure that truck was built with a 700r4 when it was new based on the year of the truck.
Chevy and GMC trucks ranging from 1973 to 2007

Offline 83HighSierra

  • Newbie
  • Posts: 96
Re: Which Transmission???
« Reply #2 on: July 15, 2007, 07:45:34 pm »
Ya thats what i was thinkin i just wanted to make sure though. Do you know how to tell the difference between a 305 and a 350 because ive had different people tell me different things about the engine too.
heres a pic of it


Offline dumbucket1

  • Too Many Trucks
  • Junior Member
  • ***
  • Posts: 597
  • Coal Hauler
Re: Which Transmission???
« Reply #3 on: July 15, 2007, 08:51:46 pm »
externally a 305 and 350 are identical. You pretty well need to located the casting numbers on the block and find a website that decodes them. If the engine is original there should be a letter in the vin that will tell you which engine it is.
Chevy and GMC trucks ranging from 1973 to 2007

Offline Captkaos

  • OWNER and Administrator
  • Administrator
  • Senior Member
  • *****
  • Posts: 18461
    • http://www.73-87chevytrucks.com
Re: Which Transmission???
« Reply #4 on: July 15, 2007, 09:13:45 pm »
All 1/2T 2wd pickups from 1981 - 1986 only came with a 305, so that will eliminate a factory 350 on those.  California excluded.

Offline 83HighSierra

  • Newbie
  • Posts: 96
Re: Which Transmission???
« Reply #5 on: July 16, 2007, 03:13:06 pm »
so i have a th350 and my gauges are off, is there a article that tells how to fix it, would it be the same as changing the gears in a 700r4?

Offline Captkaos

  • OWNER and Administrator
  • Administrator
  • Senior Member
  • *****
  • Posts: 18461
    • http://www.73-87chevytrucks.com
Re: Which Transmission???
« Reply #6 on: July 16, 2007, 04:33:41 pm »
yes, it is virtually the same as a 700R4.

Offline 1976Scottsdale

  • Junior Member
  • ***
  • Posts: 760
Re: Which Transmission???
« Reply #7 on: July 16, 2007, 06:47:44 pm »
350 engines usually have a harmonic balancer that is 8" in diameter.  a 305 will be between 6 and 7" in diameter.  That is the thing behind the pulley at the bottom of the engine.