18 auto, ANOTHER tranny problem

[Hodge71 664]

Guys, got the 18 auto back together and kinda running today and I have a problem with the gauge now. When cold after startup the gauge reads below 100, I run it for awhile and it starts to creep up to 100 and as soon as it goes over 100 it shoots up to 250 and stays there. I panicked the first time it happened and shut it off immediatedly. Checked the hydro with my hand and its lukewarm. So I start it back up and the gauge is pegged at 250 still. I checked it with my IR thermometer and its 109 degrees. yet after I left the tractor sit for an hour and go back out to check it, I turn the key on and its back to 100 again. As soon as I start it and drive her around awhile it shoots back to 250. Where is the sending unit for this thing or could the gauge be shot? Thanks for any help

[can whlvr 993]

i wouldnt trust an old gauge,if the machine moves good and stays strong when hoy she should be good

[pfrederi 17,876]

The sending unit is in the hydro pump, center rear. Go to the autoparts store and pick up a Sunpro electric temp gage (about $20). Repalce sending unit and gage 9they have to be matched) Fits fine and is a lot cheaper than Toro OEM (you can't use the mechanical version as the temp probe is too long)