What do these gauge indications mean?

[Timinator]

I have an aftermarket temperature gauge for my auto trans. Yesterday, after driving about 10 miles, it suddenly shot from 150 to 300 degrees, then the needle jumped erratically between 200 and 300. I stopped and checked the trans. No problems. The gauge behaved normally this morning until I had gone about 10 miles, then fluctuated again.
Do these wild fluctuations indicate a bad sender or a power/wiring connection problem?

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'95 2500 SLT ClubCab, automatic, 3. 54 LSD

 

[Shleets]

On many of the oil and water temp gauges, the manufacturers suggest a dedicated ground to eliminate erratic readings. Doule check the ground and if possible drill a small hole specifically for that ground and that particular gauge. When I did that the funny readings stopped. Good luck.

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Mark Schlueter
2001, QC, 4x4, ETC, K&N, White sport package. Kodiak Sidewinder Steps (front and rear). Mag Hytec diff. cover. Wet Okole seat covers with Rams head logo. VDO Vision Gauges. Three hole "A" pillar mount from Geno's. Mag Hytec Trans pan on order.

 

[illflem]

Tim,Mark is right,if you are using a sender whose body needs to be grounded don't expect to get a good ground from the AT tubing,best to use a sender that has it's own ground wire.

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95' 25004X4,AT,Driftwood,Banks Stinger,Warn fender flairs and running boards(work truck)
95 3500,5 speed 3:54,Driftwood,Banks&Psycotty,34,000 GCVW apple and tractor hauler(works harder truck)

 

[WOWZY]

Bad grounds have played havoc on some used vehicles that I've had.

 

[Timinator]

Guys,
Thanks for the input. I checked the ground and it's solid. I believe the sender has gone bad. I'll try that next.