My monte had 292,xxx miles. I have never change transmission fluid and filter. It just started slipping. Is it too late?

 

perhaps, won't hurt now to try but I'd say it's time for a rebuild.

When mine started slipping at 100k, I changed the fluid and it did nothing (might of made it worse); ended up just doing a rebuild. YMMV

 

Changing fluid most likely will kill the trans at this point. Drain a little bit via trans cooler hose and add a bottle of Lucas trans additive. Or rebuild or low miles used trans.

 

Unfortunately, I agree with z34Phoenix in respect that a fluid/filter change may just accelerate damage of the trans.

First see if the trans still has the correct amount of fluid. At that mileage who knows if it leaked any out.

I've never tried his Lucas idea, but I'd give that a shot first. If that does not yield anything and you're against a wall, you can try a trans fluid/filter change (no flushing), but be prepared for it to possibly not survive.

BTW - Congrats on almost having 300,000 miles!!!

 

I'd say the transmission is shot. Your dilemma is a common one tho. Many (if not most) people wait until they experience transmission problem to perform transmission service. Then they will say doing the transmission service ruined their transmission.

The Lucas might buy you some time. But if you got nearly 300,000 out of the transmission, I'd say it served you well

 

It's possible he is t the original owner and the trans has been replaced or rebuilt before. These Transmisions are not known to last that long even with proper fluid service. I work at an autoshop and alway have to tell customers a trans service is a "Preventitive Maintance". It is not to fix drivability issues

 

I completely agree...

As an original owner myself ... with just 167,000 miles on mine currently.
From day 1 I have always maintained mine includeing transmission fluid filter changes... However, around 90,000 miles I finally had to have the trans rebuilt.... So, with yours having almost 300,000 miles kudos to not having any trans issues with that many miles....
I haven't used Lucas trans treatment, However, I am a user,believer in Lucas products as I use there high mileage additive at every oil change on all my vehicles...
Adding the Lucas transmission treatment is a temp solution at best...
I would say, You definately got your mileage out of that transmission!
Probably the most out of anyone here on the forum!

 

Trans is toast most likely. If you change fluid it will probably.make it worse. Sounds like time for a rebuild..

 

I got car when it had 95000 miles on it. Not sure if trans got serviced before I got it but all I do is put gas in it. And try to change oil every 6 to 8000 miles.

 

Normally i say change the filter but damn, ive never delt with a tranny with that many miles. Lol. How long have you had it?