Author Topic: 700r4 question  (Read 2227 times)

Offline 73CustomDeluxe

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700r4 question
« on: March 12, 2011, 10:40:11 am »
Ok so my dad has a 1993 GMC Rally Stx 1 ton 12 passenger van. It has a 350 mated to a 700r4. We bought it a few years ago and have been using it as a church van and a driver (when my 73 is down lol). A while back we noticed that the pan seal on the 700r4 was leaking. It got so bad that you would have to check and refill it every trip. So, one day being the adventuresome "mechanic" that i am i decided to take on the task of replacing the pan filter and gasket on the transmission. I got it all back together fine. Later that day it was raining and my front tire blew causing the back to hydro plane and i went over a curb and down a steep hill. after we get the spare mounted, among the horrid alignment issues (which were resolved) i noticed the transmission wouldn't hardly pull. I looked and the filter had fallen into the pan. So I got and reinstalled a new filter and made sure it was seated right. We got new tires and fixed the alignment. The transmission would shift, but it would slip a little into over drive. A few weeks ago I was driving it on the interstate and everything was going just fine. All of a sudden the engine started to free spin. I pulled off and figured out I only had first second and reverse. We checked the fluid and the level is ok and it looks ok and doesn't smell burnt. Does anyone know what could be wrong?

1973 Chevy Custom Deluxe LWB
Every time i tear into my truck it reminds me that it's 38 years old. Most of the time it's a good feeling. Others....

Offline bake74

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Re: 700r4 question
« Reply #1 on: March 12, 2011, 06:57:13 pm »
     I am not an auto trans expert, but it does sound like the valving inside the transmission in 3 and OD Got messed up, might be time for a rebuild.
#1: The easiest and most obvious solution to any problem is 99% of the time correct.
#2: There is no such thing as impossible, it just takes longer.
  74 k10, 77k10    Tom

Offline 73CustomDeluxe

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Re: 700r4 question
« Reply #2 on: March 12, 2011, 09:42:31 pm »
thanks bake74. that's kinda what we figured. we've been calling around to transmission shops and of course they say to bring it in. Just wondering if anyone on the forum could give us advice before we drop a lot of money and time for nothing (if this isnt the case)

1973 Chevy Custom Deluxe LWB
Every time i tear into my truck it reminds me that it's 38 years old. Most of the time it's a good feeling. Others....