Needed: 1984 700R4 wiring diagram

[5akman]

The trans shop and I are wrestling with the wiring on my '84 K20. Engine is now a non smog crate 350 with newly rebuilt 700R4/Np208. We are are having issues with the wiring from the trans to the brake pedal switch and at the vac switch next to the vac brake booster. My Haynes manual doesn't show the wiring diagram for the trans controls. Anyone have a digital copy that I could refer to?

Thanks!

 

[RetroC10Sport]

Check our library, there's a copy you can download.

http://www.gmsquarebody.com/forum/showthread.php?t=14498

 

[HotRodPC]

Is this truck originally a K20? Was it originally a diesel? And being a 3/4 ton, was it originally a 700r4 transmission? Just trying to figure out if you'll have all the OEM wiring in the truck or if someone has added it?

So are you looking for OEM factory wiring for Converter Lock Up or do you have an add on aftermarket lock up kit?

 

[HotRodPC]

I'd imagine @chengny would have a stand alone OEM diagram of the Lock Up circuit. I've got the whole harness downloaded but don't have a way to cut up the .pdf to get just that part of it.

 

[5akman]

Is this truck originally a K20? Was it originally a diesel? And being a 3/4 ton, was it originally a 700r4 transmission? Just trying to figure out if you'll have all the OEM wiring in the truck or if someone has added it?

So are you looking for OEM factory wiring for Converter Lock Up or do you have an add on aftermarket lock up kit?

Yes, original gas K20 with 700R4 and all stock wiring for the tranny. I did find a good diagram online that shows a real simple wiring circuit using the brake pedal and vac switch with either one or two wire servos in the trans.

 

[HotRodPC]

Yes, original gas K20 with 700R4 and all stock wiring for the tranny. I did find a good diagram online that shows a real simple wiring circuit using the brake pedal and vac switch with either one or two wire servos in the trans.

OK, so you're good or are you still looking for a GM factory OEM wiring diagram? It is a pretty simple diagram so you may have it already.

I'd sure be interested in seeing that SPID label in the glove box with all the options on that truck. It's my understanding the 700r4 is rare in 3/4 tons. I'm converting my K10 to K20 springs and axles and I think I'm going to end up with a 700r4 too if I can find a 27 spline NP208 or NP241C.

 

[RetroC10Sport]

Not that rare, only the diesel and the 350 were available with a 3 speed auto. The K20 could be had with the 292, 305, 350 and diesel and any could have the 700.

 

[HotRodPC]

Not that rare, only the diesel and the 350 were available with a 3 speed auto. The K20 could be had with the 292, 305, 350 and diesel and any could have the 700.

hmmm, is that a K20 thing as in 4x4? I know I've not seen many C20's with a 700r4 at all, in fact I can't think of a single one. Even with 4.10 gears in 85 and 87 models had Turbo 400's. That burnt cab truck I had was one of them. 14b SF with 4.10's and Turbo 400. In fact, I just talked to that guy I bought that truck from and showed him pics of what it looked like now since I bought it how many years ago. He said he hated that truck cuz it screamed going down the freeway and drank gas like a fish.

 

[RetroC10Sport]

hmmm, is that a K20 thing as in 4x4? I know I've not seen many C20's with a 700r4 at all, in fact I can't think of a single one. Even with 4.10 gears in 85 and 87 models had Turbo 400's. That burnt cab truck I had was one of them. 14b SF with 4.10's and Turbo 400. In fact, I just talked to that guy I bought that truck from and showed him pics of what it looked like now since I bought it how many years ago. He said he hated that truck cuz it screamed going down the freeway and drank gas like a fish.

All K20s are 4x4s.

 

[HotRodPC]

All K20s are 4x4s.

Totally aware. So is it common the 4x4's got the 700r4 but the 2wd did not? You'd be the one that would know where to find out. C'mon librarian !!!

 

[RetroC10Sport]

I've seen a lot of 3/4 tons with the 700r4. Most were 350 trucks. I've been checking a bit lately because Abby's truck needs a 3 speed gear indicator. It probably needs a cluster but unless I can get to the truck while it's waiting to be put in the yard, they are hard to get.

 

[HotRodPC]

I've seen a lot of 3/4 tons with the 700r4. Most were 350 trucks. I've been checking a bit lately because Abby's truck needs a 3 speed gear indicator. It probably needs a cluster but unless I can get to the truck while it's waiting to be put in the yard, they are hard to get.

I might still have that one from one of the 81's I had. They both had Th350's with 3 speed indicators.

I didn't realize 700r4's were common in 3/4 tons. All 4 of the 3/4 tons I had, 84 through 88 all had Th400's. 2 were OEM big block, 2 were OEM 350.

 

[5akman]

OK, so you're good or are you still looking for a GM factory OEM wiring diagram? It is a pretty simple diagram so you may have it already.

I'd sure be interested in seeing that SPID label in the glove box with all the options on that truck. It's my understanding the 700r4 is rare in 3/4 tons. I'm converting my K10 to K20 springs and axles and I think I'm going to end up with a 700r4 too if I can find a 27 spline NP208 or NP241C.

I don't have a sticker in the glove box but rather on the drivers side inner fender. I'll have to check it for exact details on the trans. I believe I'm good to go on the wiring diagram as I found something online. The trans shop owner was interested in the 3 wires coming from the vac switch near the brake booster and was wondering where exactly they went.