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700r4 Question

evolve991

evolve991

Resident Problem Child
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My 'burban is an 85. I bought a "new" tranny thru Autozone( hey i was in a jam) about 6 years ago....my question is: Since I got a new one is it still considered an 85 trans or would being new include updates that would make it an 87-and-up equivalent? I looked for numbers on the casing but it's still in the truck and I can't see the top. I'm thinking of buying parts from 700Raptor but there isn't much stuff there for pre 87s. The tranny was matched for a 6.2,don't know if that changes anything.
 
IIRC the 87 and up 700R4s had a big "K" cast on the bell housing. Being it was a mass production rebuild unit, it could be anything from 82 on.
 
Guess I'll do the Braille method and feel the housing. I've seen the K on trannys,ran the numbers on one yesterday it came up as an 82 700r4 and had a K up top and VD8 lower where most say M8. My casing is devoid of markings the GMs have,was painted battleship gray when shipped,been too long to recall the stamps on it. I looked up Autozone 700r4s and they're made by Moveras but I think that's different from when i bought mine,not sure if they changed suppliers since.....
 
Hopefully the builder can match your serial number to a build sheet or something. There are a lot of parts in side that can be updated to later model but the case itself will look just the same - like planetaries, pump, sun shell, sprags. For all you know, it's full of whatever parts they had on hand at the time. As for the case, the big change I'm aware of is the addition of the auxiliary valve body. I'm kind of confused on this because earlier cases also had provisions cast in for it, but I have no idea what it takes to put the aux valve body in an older case. Depending on what kind of upgrades you want, I think a lot of them would work in any year 700. Why not ask PATC?

I think the only difference between the gas and diesel versions is the weight/spring combination in the governor to set different shift points.
 
evolve991 said:
Guess I'll do the Braille method and feel the housing. I've seen the K on trannys,ran the numbers on one yesterday it came up as an 82 700r4 and had a K up top and VD8 lower where most say M8. My casing is devoid of markings the GMs have,was painted battleship gray when shipped,been too long to recall the stamps on it. I looked up Autozone 700r4s and they're made by Moveras but I think that's different from when i bought mine,not sure if they changed suppliers since.....
Click to expand...

6 years ago Shift management inc was the supplier for Autozone and their trade mark is painting the case battleship grey.
IIRC when I taked to them they said they put all the upgrades that were made in 87+ to all their rebuilds for all the base model rebuilds.
You should have a good rebuild.
Are you having problems or you just want to upgrade with raptor parts to make it better?
If it still runs good, I say leave it alone.
 
Diesels had a lower stall speed torque converter factory,than a gas version...along with the govenor recalibrated to upshift sooner...
 
I expected problems out of the TC and governor but the shift points seemed fine so I let it ride.
I ran low on fluid and trans slipped a little at a red light,I pulled over and put a quart in and it dropped right into reverse and low like normal....it shifted fine until 3rd....it didn't redline,smoke,squeal or grind...just acted like it couldn't quite get into 3rd...I changed fluid/filter...no metal,not much metallic tint at all,no sludge but fluid needed changed anyway....so..would there be junk from a fried 3rd clutch pack? Metal from ate up internals? I'm thinking maybe stuck valve....again I bought this trans new 6 years ago,it's my daily ride,no 4wheeling,no towing,no shift kits,rippin' n tearin'....ah man just shoot me....
 
If you don't know what's wrong with it, why are you looking to swap parts?

The only easy things to fix on these units are the TV cable, the governor, the servo and the TCC solenoid. However, your symptoms don't point directly to any of these.

You could put a gauge or pressure switch on the 3rd pressure port to see if the valve body is shifting right. A transmission shop might have a gauge with a long hose (i.e. bring it in the window) and help you with the troubleshooting. Although a lot of them will just want to tear it out and do a rebuild and have no interest in helping like this. So if you have pressure but no 3rd/4th, there is a bad seal or a blown clutch pack. Either way = tear it apart.

If there is no pressure, the problem could be a blown gasket (accumulator, etc) but it's probably worth pulling the valve body out to clean it. The valve body can be pulled just by dropping the pan, but you have to be very careful not to lose the check balls above the separator plate. Same thing with the valve body once you get it out. Now there are 100's of ways to screw up the valve body if you start disassembling it, but it can be done successfully if you go 1 valve at a time and lay everything out in order.

Before pulling the valve body you might try taking a pick up from underneath and "flick" each of the valves through the access holes to see if they all "snap back". This process could free something up. The bad news is that sometimes valves stick for a reason and there is something making debris.
 
when mine quit shifting into 3rd, it was toast, had high mileage on it though, daily driven for awhile with about 200 or so miles per day.

245k before it said,, "I QUIT"
 
I'm planning ahead in case its a clutch pack or something else fixable. PATC states most parts are for 87 and up. I'm broke,stubborn and insane enough to contemplate fixing it myself. I'm running ideas by you guys to see just how insane those ideas are:dunno:


I didn't read your entire post before replying Blue,thanks for the info!! I'm being hardheaded about this because I bought the damn thing new,it doesnt have THAT many miles on it,I learned about the TV cable headaches a few 700r's before buying this one,I didn't abuse it greatly and i don't have 2 grand to get a new one now.
 
diesel4me said:
Diesels had a lower stall speed torque converter factory,than a gas version...along with the govenor recalibrated to upshift sooner...
Click to expand...
Yup, you need to get the "proper parts..." theres a few minor internal differences between a gas and diesel 700R4... and there needs to be a diesel type TC coupled to it... theres a difference in the poppit valve there... Its all setup for the RPM ranges of the 6.2, which is NOT anywhere close to a gasser setup...

GL,
Andrew
 
Seriously, didn't they ask you if it was a gas or diesel engine when you ordered the tranny? You probably would have noticed right away if it had the higher stall converter and the gas governor. You may not have been able to reach the shift points except at lower throttle.
 
Yep,they asked and sent one for a diesel. I know I'll hear lots of flack over this. The tranny was in and rolling before i ever read anything about differences between the TCs and since it did not fail,slip,rev,crack,leak,slam,scream,squeal,chatter,thunk or send shrapnel thru my floorboard for oh about 4 years now I didn't change it. i assumed it was a difference like the one between Chevelle and Skylark parts......dollars......and not much else........
 
On the passinger side rear corner of the trans, just above the pan there is a serial # Post it and I can tell you what year it is. Ideally you want an 87 or newer trans. it will have the auxillary valve body and 10 vain pump. The problems your describing dont sound like something your going to fix without pulling the trans.
 
Thanks olanchamedic I'll get that as soon as I can. I've already given in and will be getting a crapshoot trans somewhere I just refuse to give up on a new-ish trans I dropped so much on.....us construction grunts don't get to throw expensive stuff away every weekend LOL......
 
Anyone ever have to persuade a broken governor gear out of the tranny? I finally had time to crawl under there and check the gov....half came out,half didnt....
 
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