Author Topic: 700r4 rebuild?  (Read 2750 times)

Offline 82apache

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700r4 rebuild?
« on: December 09, 2019, 07:14:31 PM »
'82 K20, near as I can tell it has the stock 700r4 and it is time for a rebuild. The future says no motor over, call it 350hp to be safe, occasional maybe 800lb hauling, occasional towing up to maybe 4000lb, occasional light off-road use. 
Call it, a daily driver that will get a little exercise now and then.

Recommendations? What should I be asking for at the rebuilder or...?

Offline Irish_Alley

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Re: 700r4 rebuild?
« Reply #1 on: December 10, 2019, 10:10:45 AM »
best thing to do is go to a trans shop and tell them what you intend on using it for with your power output. they should be able to build it to your specs with no issue. it doesnt sound like you need a HD trans but you might just want to have it built to be able to handle the future abuse without hurting the trans
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Offline JohnnyPopper

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Re: 700r4 rebuild?
« Reply #2 on: December 10, 2019, 08:46:59 PM »
There is a year range of good 700r trans, have heard that from others, maybe even here. Do some research on which was best.

What is the issue with yours? With regular maintenance they go and go...
1957 Apache 3100 235 Inline 6, 3 on the tree
1973 C-20, 3+3 454 4BBL TH400  Water Injection
1978 K-10, 350 4BBL TH350 NP203 M.M. Part time Kit/Hubs
1980 C-10 under construction

Offline Irish_Alley

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Re: 700r4 rebuild?
« Reply #3 on: December 11, 2019, 07:11:30 AM »
the 700r4 generally got better the longer they were in production due to upgrades. if you get one rebuilt it should automatically come with those upgrades
If you can’t tell yourself the truth, who can you tell it to?~Irish_Alley

When you have eliminated the impossible, whatever remains, however improbable, must be the truth ~Sherlock Holmes

Offline 82apache

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Re: 700r4 rebuild?
« Reply #4 on: December 16, 2019, 02:10:41 AM »
There is a year range of good 700r trans, have heard that from others, maybe even here. Do some research on which was best.

What is the issue with yours? With regular maintenance they go and go...

Reverse is gone and and now it is stuck in a forward gear even while in park. She is toasted. But it a fair bet it is the original so it was time. And time to shed the reliability question any 37 yo old trans has.

Offline 82apache

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Re: 700r4 rebuild?
« Reply #5 on: December 16, 2019, 02:37:00 AM »
the 700r4 generally got better the longer they were in production due to upgrades. if you get one rebuilt it should automatically come with those upgrades

You would hope so but I am not even smart enough on the subject to be dangerous. lol

Offline Irish_Alley

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Re: 700r4 rebuild?
« Reply #6 on: December 16, 2019, 02:32:59 PM »
You sure the shifting linkage is still connected right?
If you can’t tell yourself the truth, who can you tell it to?~Irish_Alley

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Offline 82apache

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Re: 700r4 rebuild?
« Reply #7 on: December 17, 2019, 01:19:48 AM »
You sure the shifting linkage is still connected right?

Yes.

Offline VileZambonie

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Re: 700r4 rebuild?
« Reply #8 on: December 17, 2019, 08:20:20 AM »
I wouldn't rebuild your trans. Find a later model 700R4/4L60 or get an exchange unit. Too many design flaws in the early units and not worth rebuilding.
,                           ___ 
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              ⌠¯¯¯¯¯'   [☼===☼]
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74 GMC, 75 K5, 84 GMC, 85 K20, 86 k20, 79 K10

Offline 82apache

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Re: 700r4 rebuild?
« Reply #9 on: December 17, 2019, 10:39:08 PM »
I wouldn't rebuild your trans. Find a later model 700R4/4L60 or get an exchange unit. Too many design flaws in the early units and not worth rebuilding.

Well now,  that throws a spanner in the works.


Offline VileZambonie

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Re: 700r4 rebuild?
« Reply #10 on: December 18, 2019, 05:52:39 AM »
Sorry, but 82 was the worst year for them too. 88-92 are the good ones. You can buy an exchange unit now relatively cheap with a decent warranty which will handle 35"s and mild towing. If you are doing anything more than that consider a high performance unit. I've rebuilt enough of the earlier units with all of the updates and modifications and still never been fully satisfied with the behavior so I always find a later model unit.
,                           ___ 
                         /  _ _ _\_
              ⌠¯¯¯¯¯'   [☼===☼]
              `()_);-;()_)--o--)_)

74 GMC, 75 K5, 84 GMC, 85 K20, 86 k20, 79 K10

Offline JohnnyPopper

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Re: 700r4 rebuild?
« Reply #11 on: December 18, 2019, 10:57:32 AM »
I KNEW someone would know the good years! Leave it to VZ! Thanks, mental note for next project...
1957 Apache 3100 235 Inline 6, 3 on the tree
1973 C-20, 3+3 454 4BBL TH400  Water Injection
1978 K-10, 350 4BBL TH350 NP203 M.M. Part time Kit/Hubs
1980 C-10 under construction

Offline MIKE S

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Re: 700r4 rebuild?
« Reply #12 on: December 18, 2019, 12:02:26 PM »
The first year for the 700r4 which is 1982 was so bad for failures that GM issued a recall to replace the transmission before it failed. Which was usually while they were being unloaded off the transport truck.

Offline JohnnyPopper

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Re: 700r4 rebuild?
« Reply #13 on: December 20, 2019, 11:40:14 AM »
 :o

 ;D ;D
1957 Apache 3100 235 Inline 6, 3 on the tree
1973 C-20, 3+3 454 4BBL TH400  Water Injection
1978 K-10, 350 4BBL TH350 NP203 M.M. Part time Kit/Hubs
1980 C-10 under construction