700R4 Information Thread

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chevytech87

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Getting ready to put a fresh rebuild in my truck, might be a dumb question but what fluid should I run? Can you get dex 3/4 anymore? I believe that was the recommended fluid for this unit.
 

NickTransmissions

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Getting ready to put a fresh rebuild in my truck, might be a dumb question but what fluid should I run? Can you get dex 3/4 anymore? I believe that was the recommended fluid for this unit.
Any Dex/Merc certified fluid will do. Dex VI is said to be backwards compatible but not necessary.
 

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Very cool recollection...Do you remember installing, adjusting a TV cable? If not or one was never installed, it's a good bet that a CP valve body was involved. Also, the fact it lasted only 20k miles lends more credence to one being on that trans since that's about how long they typically last (5-20k miles) in a street driven application. Pump rotor/rings/slide likely shattered.


Yes, their main draw is the mechanical TCC lock up control capability...no need for an electro-mechanical internal/external lock up kit for non-stock applications...My resto-mod customers love that sine they don't want to spend time and money monkeying with electrical stuff on a 30s,40s,50s,60s vehicle and the 1st gen valve bodies let you control the converter clutch automatically via the forth bore on the shift valve side of those 1st design valve bodies.

The 2nd design and 3rd design, 88-92, 93 respectively, don't have that 4th bore - it was casted over entirely...

The preferred approach for any performance application involving a 700R4 is to use an 88+ core with an 82-87 valve body to give you the best of both worlds...The 88+ 700R4s have the most updated input drum, 29 element input sprag, wider low roller clutch/center support, 10-vane pump assemblies, aux valve bodies for softer garage engagement into drive and a better engineered low-reverse circuit.
OK, that was it then. I was 2nd guessing. I have 2 or 3 early cores. I'll probably pull the valve bodies and trash them. If and when I do build them anymore, it's an 87 or later. Haven't built one now in about 20 years.
 

Bextreme04

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Getting ready to put a fresh rebuild in my truck, might be a dumb question but what fluid should I run? Can you get dex 3/4 anymore? I believe that was the recommended fluid for this unit.
Like Nick said, Dex 3 or later. I run the blue bottle Valvoline Dex/Merc fluid from walmart in my TH400's and 4L80 that call for Dex III. It's $18/gallon. I run the red bottle Valvoline Maxlife or ACDelco Dex 6 in my 6L80 that calls for Dex 6. You can get it for $24/gallon at walmart. The synthetic Dex VI is better with heat, so if you aren't going to run a BIG external cooler with your 700R4, I'd spring for the extra $5/Gallon and use the Maxlife.
 

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OK, that was it then. I was 2nd guessing. I have 2 or 3 early cores. I'll probably pull the valve bodies and trash them. If and when I do build them anymore, it's an 87 or later. Haven't built one now in about 20 years.
Don't trash those early cores, simply converter them to the L84-87 standard via swapping in a '152' input drum (30 spline) and 303/304 pump cover and body assembly (non-aux valve body style pump). Install the updated 29-element input sprag gear assembly, 4L60E forward wave/cushion plate, coast clutch backing plate and 4L60E 3-4 steel module and you'll be good to go. 700R4s are getting very hard to find so even those early 82-84 27-spline units are fetching over $300 as rebuildables here in Vegas.
 

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Wow, that's just nuts. But yeah, I see what you're saying. Makes sense and now I have a justifiable reason to KEEP JUNK around. I thinik I have 2 82-84 and 1 85-86 and 3 or 4 88 up, 2 of them being 93 year models.
 

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Wow, that's just nuts. But yeah, I see what you're saying. Makes sense and now I have a justifiable reason to KEEP JUNK around. I thinik I have 2 82-84 and 1 85-86 and 3 or 4 88 up, 2 of them being 93 year models.
I think we all need more reasons to keep old junk around, especially when talking about complex assemblies like driveline or even certain suspension/steering parts. The future is not going to be kind to l e g a c y technology and will try to tax or regulate it out of existence
 

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I think we all need more reasons to keep old junk around, especially when talking about complex assemblies like driveline or even certain suspension/steering parts. The future is not going to be kind to l e g a c y technology and will try to tax or regulate it out of existence
I've got $hit laying around I'll never use. I know it's good to someone. Some of it I do want out of my way. My main deal is, I want in the hands of someone who'll use it or needs it. I can't see scrapping it. Like these older 700r4 cores. I've known for sometime I'd never build them for anyone or sell them, but I knew the valve bodies in them were good, and I was hoping maybe they'd been rebuilt before and I might open then up and find Beast Sun Shells in them since just about every rebuild gets at the bare minimum a Beast Sun Shell. However, now days, there's the Smart shell which is by far better and worth it all day long, but there is also China made SAID TO BE the BEAST sunshells and they are NOT. Buy yeah, guess I'll keep them around for case cores. One of my 93 cores does have a broken bell housing. So see, what Nick is saying, and I knew many parts are backwards compatible, so I can likley use those hard parts and make one of these older cases good, especially for someone wanting to do a #'s matching restoration project. Some people are picky that way. They want the right #'s on the case, or many 60's build guys want the right tag on the Th400 or Th350 case.
 

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I just purchased a 1984 GMC half ton 2wd. It has a rebuilt 350 and what I believe is a 700R4. Number on the side is 4YP00B. My question is about the cross member holding the transmission up. I noticed today that it does not run straight across. It is **** eyed. I took the bolts loose to try and get it straight but it"s not happening. On one side there is only one bolt because of the way it sits the other hole doesn't line up. I don't believe the truck came with a 700R4.
Is there supposed to be a diffefent cross member. Is the cross member I have supposed to work with a different transmission? Is there another I could get that would line up properly? If so, where do I get it and what do I ask for?
 

NickTransmissions

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I just purchased a 1984 GMC half ton 2wd. It has a rebuilt 350 and what I believe is a 700R4. Number on the side is 4YP00B. My question is about the cross member holding the transmission up. I noticed today that it does not run straight across. It is **** eyed. I took the bolts loose to try and get it straight but it"s not happening. On one side there is only one bolt because of the way it sits the other hole doesn't line up. I don't believe the truck came with a 700R4.
Is there supposed to be a different cross member. Is the cross member I have supposed to work with a different transmission? Is there another I could get that would line up properly? If so, where do I get it and what do I ask for?
Go to Pick-a-Parts and start looking at GM Squarbody trucks in the yard, particularly at the trans cross members and relationship to the frames. Maybe take one that looks 'correct' loose to see how it would sit/set up prior to being bolted back in place. What you're trying to determine is if your x-member is correct, whether the x-member is tweaked/warped and/or whether your frame rails are tweaked/warped.
 

Ricko1966

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I just purchased a 1984 GMC half ton 2wd. It has a rebuilt 350 and what I believe is a 700R4. Number on the side is 4YP00B. My question is about the cross member holding the transmission up. I noticed today that it does not run straight across. It is cockeyed. I took the bolts loose to try and get it straight but it"s not happening. On one side there is only one bolt because of the way it sits the other hole doesn't line up. I don't believe the truck came with a 700R4.
Is there supposed to be a diffefent cross member. Is the cross member I have supposed to work with a different transmission? Is there another I could get that would line up properly? If so, where do I get it and what do I ask for?
Can you unbolt the mount from the frame put it in the way it needs to go and redrill the frame. You have have to add a piece to the cross memberto make the mount pad stick out far enough to hit the mount. A piece of 3/16 plate and a little common sense should get it done.
 
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HotRodPC

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I just purchased a 1984 GMC half ton 2wd. It has a rebuilt 350 and what I believe is a 700R4. Number on the side is 4YP00B. My question is about the cross member holding the transmission up. I noticed today that it does not run straight across. It is **** eyed. I took the bolts loose to try and get it straight but it"s not happening. On one side there is only one bolt because of the way it sits the other hole doesn't line up. I don't believe the truck came with a 700R4.
Is there supposed to be a diffefent cross member. Is the cross member I have supposed to work with a different transmission? Is there another I could get that would line up properly? If so, where do I get it and what do I ask for?
I'd say it did come with a 700r4. That was the most common transmission by 84 and your 4YPOOB, the 4 would designate an 84 model so it's likely the OEM transmission. Even if it were a Th350, I'm 95% certain, either transmission would use the same crossmember, they just might use a different set of frame punched bolt holes. One will set the crossmember a bit futher back than the other.
 

HotRodPC

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Can you unbolt the mount from the frame put it in the way it needs to go and redrill the frame. You have have to add a piece to the cross memberto make the mount pad stick out far enough to hit the mount. A piece of 3/16 plate and a little common sense should get it done.
I'm slow, it took me a minute to figure what the **** was in your post. I was going to correct it and use a 0 in **** but then realized, if you take the space out that doesn't belong, we can say cockeyed. :lol:

Oh, and I guess the filter is smarter than us and we can't Kock. Cuz even using a Zero for the O, it's still ****.
 

Bextreme04

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I just purchased a 1984 GMC half ton 2wd. It has a rebuilt 350 and what I believe is a 700R4. Number on the side is 4YP00B. My question is about the cross member holding the transmission up. I noticed today that it does not run straight across. It is **** eyed. I took the bolts loose to try and get it straight but it"s not happening. On one side there is only one bolt because of the way it sits the other hole doesn't line up. I don't believe the truck came with a 700R4.
Is there supposed to be a diffefent cross member. Is the cross member I have supposed to work with a different transmission? Is there another I could get that would line up properly? If so, where do I get it and what do I ask for?
Transmission mount is ~3/4" further back on a 700R4 than it is on a TH350. Both TH350 and 700R4 were available in 84, and it was the last year for the TH350. You could look at your SPID sheet to see what one your truck came with from the factory. MD8 or MX0 is the RPO for a 700R4. MX1/M38/M49 are the RPO's for a TH350. M40 is the RPO for a TH400

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