88-94 to 95-98 All Swap Info Compile

[BigBody90]

What would happen in my 90 if I swap the gauges to custom ones and do not use a drac? Will my truck run weird or will I just throw a code? My cruise control never worked and my abs has never worked so those are of no concern.

[chevyz71man]

mstefak you need the drac because in your truck the the VSS signal is converted in the cluster. The 92 and up is converted in the DRAC unit. The speedo will not work unless you have a DRAC. The only reason they moved the signal converter outside the cluster was to accomidate ABS and for the electronic tranny controls in the ECM. BUT YOU STILL NEED IT

[chevyz71man]

on your 90 it will run fine without it. Your truck does not have a computer controlled tranny. Pull the cluster out, dont add a DRAC and the computer wont have any clue its missing. You will be fine without it.

[Frankenbiker]

The ECM does use the speed signal for one purpose: determing lockup points on the TCC. Depending upon whether or not you're running custom PROM programming, it sometimes looks at speed to determine cruise-mode leaning (for mileage) but it should run all right without the speed signal.

The TH700 does NOT like being run in OD without the converter locked up. If you want to run for a couple of weeks before you get the whole thing finished, wire a simple lock-up switch so you can trigger lockup manually. the easiest way to do this is to ground out the F terminal on the ALDL connector. You can do it with a paperclip between the A and F terminals, but that results in lockup in 2,3, and 4, and the shifts are MURDER. Otherwise just wire a simple on/off switch between the two terminals and toggle as needed.

-blaine

[chevyz71man]

Well then I guess my mistake I thought only the 4l60 connected to the computer for TCC lockup and the 700r4 didnt..

[Frankenbiker]

The 4L60E needs the computer to tell it when to shift. It's completely computer controlled. The 4L60(no-E)/TH700 only require the computer for lockup control; shifting is done completely by hydraulics.

-blaine

[MStefak]

So i dont need the DRAC right away ? Since i have a 5spd ?

[BigBody90]

Does no speed signal to the ecu create a problem with a turbo 400 or just the th700r4. Does cruise mode learning mean locking the tranny up completely while cruising?

[chevyz71man]

a th400 doesnt need anything from the computer.

mstefak,
You need the drac for the speedo to work in the cluster.

[MStefak]

Ah **** I dont even know how fast im going now it wont hurt haha.

[MStefak]

Well picked up my 98 Dash today and could not resist I tore the old one out and put the new one in :) Tomorow paint will go on and i hope I get the cluster wired in! Anyone have any type of advice ?

[wilbilt]

I have factory wiring diagram books (the big ones) for '88 and '92, if there is any info in there that will help.

Sorry, I don't have anything newer (but I'm working on it).

[MStefak]

So far I think I've got everything covered. Project2005 was kind enough to provide a chart for the swap and in the next month of so im looking at getting a 95 harness to replace my 88 one. If there is anything I think of I'll be sure to ask :)

[MStefak]

Well I went to do the cluster wiring today and ... Where is A and where is Z ?

The only way I know how to label the 88 style plug is 1-17 A and B ...

But Project2005 you say A - Z ..

[chevyz71man]

the 88 plug is different then the 92-94 plug. Thats why

[MStefak]

I figured as much :P So how do I figure this out?

[Otto]

buy a 88-91 wiring diagram book and tace all the wires one by one. have fun!

[christid01]

OK, I'm new here, got sent here from another site, read the entire thread and still have some simple questions. I have a '94 2WD AUTO, so I have a DRAC in my truck ... ? Will that DRAC work with the 95 and up cluster, or will I need to change it out?

[BigBody90]

Yes it will work. The only people that have problems are 88-91 where the drac is built into the moonie style gauges.

[MStefak]

Bigboy .. did you do the column ? Who has done the column ? This is the last thing i need to do and just want to hear what everyones got to sway about it.