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No overdrive on TH700R4 in 1985 GMC K1500

This is a discussion on No overdrive on TH700R4 in 1985 GMC K1500 within the Technical / Maintenance forums, part of the General Discussion category; Another question for you guys... I just bought myself another truck this week, a 1985 GMC Sierra K1500 with a ...

  1. #1
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    No overdrive on TH700R4 in 1985 GMC K1500


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    Another question for you guys...

    I just bought myself another truck this week, a 1985 GMC Sierra K1500 with a 305/TH700R4/NP208.

    Beside the wimpy 10 bolt rear and 305 the truck is great! And surprisingly clean for what used to be a daily driver that will now be my second weekend toy around town...

    The only problem I got with it. and the seller had told me about it, is the overdrive that doesn't come up....Nothing at all...It stays in third just like a TH350. I didn't drive it on the highway yet, but the former owner did, and it didn't shift the time he owned the truck for a year.

    I off course looked under to confrim it is a 700R4 and it really is a 700R4 not a TH350, since it was obvious the former owner was not a die hard chevy truck specialist...

    Could it be a solenoid, the TV cable that need adjustment, or something more expensive related to valvebody or such? I've owned several 73-87 Chevy trucks but this one's my first with a 700R4....

    Any idea?

  2. #2
    Registered User daved931's Avatar
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    Re: No overdrive on TH700R4 in 1985 GMC K1500

    Is that new enough to have electronic lockup? Could be TV cable adjustment.
    1999 2 Door Tahoe 4x4 w/ 14 Bolt SF & TruTrac. All kinds of upgrades, SOLD 1/2012
    2008 Silverado 1500 Z71, leveling kit, exhaust, SOLD 9/2014
    2014 Silverado 1500 Z71, stock for now

  3. #3
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    Re: No overdrive on TH700R4 in 1985 GMC K1500

    im guessing its the cable adjustment. I dealt with this in depth on my 82 when I had to have the 700r4 rebuilt. Just a little bit off in one direction or the other will make the tranny do some weird sh*t

    2000 Silverado Z71 ECSB Stepside LT
    5.3L, 3.73, K&N CAI, Flowmaster muffler

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    Re: No overdrive on TH700R4 in 1985 GMC K1500

    About the lockup I really don't know...I will have to check. The shifter has D and DD...I guess it doesn't help much....I know the difference between a TH350 and TH350 lockup, the electrical harness on the side, is it the same thing for the 700R4???

 

 

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