# Heat not working, and transmission prob



## 90maxima (Oct 20, 2005)

In my '90 max, its an auto btw, yea i know i know... haha, anyways... all of a sudden my heat does not work anymore... my friend who works on my car since he knows a lot took out the whole heat unit, my head unit... took all of it out to see what the problem was, and theres nothing wrong with the cables or anything... i know its not the heater core either because if it was my car would be overheating but its not... my temperature goes up but cold air blows out. im thinking its because my thermostat is staying open and not closing, so im gonna buy a new one and replace it. anyways about my transmission, when i shift sometimes, as if i hit the gas really hard it will rev and not go, only sometimes this happens tho.

my transmission fluid is black and i think the filter is clogged. i ordered a new filter which just came in and i have it, im about to put it in and replace the tran fluid, is this a good call? my car has 149,000 miles on it... some say i shouldnt replace the filter/fluid but honestly i think i should, and if there are still problems.... then yea, my tranny is about to go.

thoughts? comments? that'd be cool 

thanks!


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## internetautomart (Mar 8, 2004)

90maxima said:


> In my '90 max, its an auto btw, yea i know i know... haha, anyways... all of a sudden my heat does not work anymore... my friend who works on my car since he knows a lot took out the whole heat unit, my head unit... took all of it out to see what the problem was, and theres nothing wrong with the cables or anything... i know its not the heater core either because if it was my car would be overheating but its not... my temperature goes up but cold air blows out. im thinking its because my thermostat is staying open and not closing, so im gonna buy a new one and replace it. anyways about my transmission, when i shift sometimes, as if i hit the gas really hard it will rev and not go, only sometimes this happens tho.
> 
> my transmission fluid is black and i think the filter is clogged. i ordered a new filter which just came in and i have it, im about to put it in and replace the tran fluid, is this a good call? my car has 149,000 miles on it... some say i shouldnt replace the filter/fluid but honestly i think i should, and if there are still problems.... then yea, my tranny is about to go.
> 
> ...


you might be low on antifreeze or have pockets at the heater core which would be remedied by bleeding the system.

the 90 trans doesn't have a replaceable filter unless you plan on taking out the entire transmission


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## CBPMIKE (Feb 2, 2005)

*Heater problem*

I had a similar problem with an 89 Max. Open the hood and look at the firewall - almost dead center. There is a round "plunger" type valve with a vacuum hose. This valve regulates hot and cold air and can become stuck. Simply move the plunger valve in or out and see it heat works - it did for me. Good luck


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## CT_Nismo (Dec 25, 2005)

I have a 90 Max GXE auto.......correction......rebuilt auto.

Yep, the tranny will exhibit strange shifts and other goofy behavior when its time has come.

Sooooooooo $2,000 later, I have a crisp shifting rebuilt tranny. The degradation that lead to the repair was so slow that I did not notice. But the rebuilt is real nice.

Yeah, yeah.....it's stupid to put that much cash in a 16 year old car.


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