Moonie to needle cluster swap

I have a fully rebuilt 91 needle cluster I’d be willing to part ways with. It’s out of a 5 speed, with a v6. If you are interested.

Reviving…

I have a 91 sport 4wd with the moonies. I just scored a 91 needles cluster from a V8 truck. The gear ratio/2wd/4wd status from the doner truck is unknown.

If I am following this thread correctly…. Since I am doing a 91 needles to a 91 truck, it should be direct plug n play, only possible gotchas are tach/speedo. Since my doner is a V8 then tach should be fine. Only speedo may be slightly off, If doner was a 2wd with a 3.42 gear and I have 4wd so 3.73 gear…. Sound right to you guys?

Redsled said:

Reviving…

I have a 91 sport 4wd with the moonies. I just scored a 91 needles cluster from a V8 truck. The gear ratio/2wd/4wd status from the doner truck is unknown.

If I am following this thread correctly…. Since I am doing a 91 needles to a 91 truck, it should be direct plug n play, only possible gotchas are tach/speedo. Since my doner is a V8 then tach should be fine. Only speedo may be slightly off, If doner was a 2wd with a 3.42 gear and I have 4wd so 3.73 gear…. Sound right to you guys?

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91 to 91 you'll be fine, yes, other than the two concerns you legitimately bring up. If both trucks were V8 gas engines then the tach is a non-issue. Speedometer will likely need recalibrating, because for it to be correct, the donor truck would need the original tire size and axle ratio to match your truck, which isn't likely.

Richard

someotherguy said:

91 to 91 you'll be fine, yes, other than the two concerns you legitimately bring up. If both trucks were V8 gas engines then the tach is a non-issue. Speedometer will likely need recalibrating, because for it to be correct, the donor truck would need the original tire size and axle ratio to match your truck, which isn't likely.

Richard

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Cool thanks! The seller said most of their donors are 4wd. I am still running the OEM tire size…. So at least I have a chance! Cmon baby big money no whammies!!! Lol

Redsled said:

Cool thanks! The seller said most of their donors are 4wd. I am still running the OEM tire size…. So at least I have a chance! Cmon baby big money no whammies!!! Lol

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It's easier than you'd think, and cheap, to install a DIP switch and make it infinitely configurable: https://www.gmt400.com/threads/recalibrating-1988-1991-speedometer-dash-cluster.62022/

Richard

Why don't you just remove the gauge panels from both clusters, see how your resistor/fuses are established for your gear ratio and mimic that on your new cluster?

Leeztruk said:

Why don't you just remove the gauge panels from both clusters, see how your resistor/fuses are established for your gear ratio and mimic that on your new cluster?

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He would have to remove the fuses from circuit (desolder) and test them with a multimeter to see if they're open or closed. Then desolder them from the new cluster, and solder them back in place in the correct order. Easy enough. What's easier is soldering a DIP switch in there instead, and set it according to how the original cluster was set. That way he's future-proofed it for re-gearing, or changing tire sizes.

Richard

Got the gauges in. Everything works as it should except the speedometer. I haven’t tested it officially so to speak, but it definitely seems to register a bit faster than my actual speed. So now Ill have to read up more on your info on how to correct this.

I appreciate all the info.

One more thing I will point out in case someone else is going down this path. My new cluster did not come with the protective plastic lens. One thing I discovered was the trip push button is in a different place with the needles vs my moonies so I had to drill a hole in my existing cover to make it work. I will use that temporarily until I can find a lens from a needles cluster. Hopefully one in better shape because my existing lens has a couple scratches in it!!

Pulled my needles cluster to pop in LED bulbs and run some tests based on my new found speedometer knowledge.

My moonies have continuity in fuses 1,4,5,7. 2,3 and 6 do not. This is correct per the GM chart for a 3.73 gear with 265/70/16 wheels, which is exactly what I have.

My needles have continuity in 1,6,7. 2-5 do not. Per the GM chart this is for a 3.08 gear with 235/75/15s.

So I need to either pop in the DIP…. Or make the needles match the moonies. I think I will the dip route. Not because I ever plan to change wheels/gears but after seeing both methods and reading here, that seems to be the easiest option to me.

I have soldered a couple of times but never on a circuit board. I am a little nervous about it because I will lose my mind if I booger up my circuit board!! Any tips/advice on this is always appreciated!!