greetings nerds it's been crazy hot lately.
it reached 115F last week and my tranny just started to slip and wouldn't shift out of 1st it was so hot i assume close or over 200f.
it happened before. last summer when it was over 100 out.

on a 90F day i got home from work, checked the pan, it was 196F

i'm wondering if you guys run trans coolers? i'm looking at this for a thermostat

and the cooler itself idk what can fit behind there haven't looked.
seems like coolers are manditory on these cars when it gets over 90 outside at least.

 

Tranny cooler is necessary if you're racing, daily driving and it overheats, naw'man, there's likely something else wrong. Have you had it service lately? fluid swapped? How many miles are on it?


All I'm saying is, these cars are built to run in hot climates, for you to overheat like that you need to fix the mechanical issue before you go getting a fluid cooler...

 

serviced in what way?

 

Have you taken it to a tranny shop for this problem, or have you had the trans fluid replaced recently? If not, start there before you waste your time running a cooler system. Fluid swap needs to be done at specific interval, check your manual, not sure myself for your year. But if you have high mileage and haven't swapped fluid in a while or ever, that's the first thing you need to do. But that said, if there is slipping, you may have mechanical problems internally. Only a transmission shop can troubleshoot those problems. Even a dealership may be hit or miss, often times all they do is swap tranny's, they don't spend a ton of time diagnosing.

 

just wonder what trans temps do you see on a hot day?

 

I suppose people can argue either way on a cooler. I've read a bit and it seems hot climates are prime candidates for the coolers. And of course aggressive driving or city driving or racing.

Considering your hot climate I would not only change the fluid but put in a cooler. Assuming it was ok prior to the 115 degrees then I would further assume the hot weather is to blame and maybe compounding the issue might be old fluid.

If it were me I would change the fluid asap and plan on a cooler. They are not expensive. If you don't get particular on fluid changes for the trans then that hot weather will just take it down a bad path.

Thus, the reason for the cooler AND new fluid. I personally wouldn't risk anything assuming it was ok before the hot days.

 

Replacing fluid can sometimes be the culprit. If your car has a quarter of a million miles on it and the fluid hasn't been replaced in 100k, changing it will often introduce issues such as slipping, soft shifts, wacky shift points, etc.. If your car is up there in mileage, and your tranny fluid is old but but the tranny shifts fine, leave it alone. It's already on it's way down, no need to speed up the process.

 

How does a new fluid on 200K miles tranny introduce issue like slipping and soft feel? It seems counterintuitive to me.

A popping gear could be caused from worn synchro, worn shift forks, worn sleeve, or improper/worn linkages. It could also be the internal detent spring fatigue.

Maybe the clutch fluid is old or the rubber line between the slave and hard line is old that it is expanding during hot temp causing some weird stuff. Or just simply need new clutch. I know that when my clutch started to slip, it was worse in the hot day and much better in the morning.

 

I failed to include critical info, my statement applies to high-mile automatics. If the fluid is old, the transmission is actually accustomed to working in that condition. If you change the fluid, and thus the consistency of the fluid, you risk interrupting it's normal working condition, and introducing the possibility of accelerated damage and/or failure. Best approach is to change regularly. This applies if the history of the fluid or it's age is unknown or known to be far overdue.

 

I was assuming that it was manual tranny, my bad.

 

And I presumed auto! Set us straight, OP!

 

Sounds like junk fluid to me or shift solenoids don't like the heat. That's normal operating temp for the engine in the summer...which is tied to the tranny. Your temps are normal.

I'm tellin ya...****mart HM dexron III and lubegard XD

 

That's the thing, replacing the fluid doesn't cause the problem, the mechanical problem already exists, replacing the fluid exposes the problem sometime a little more quickly. That said, if you're experiencing odd symptoms, take it to a tranny shop, see what they think. All the rest of this is speculation. But to do what User1 suggests is like putting electrical tape over the check engine light, sure, you can pretend like there's nothing wrong and just keep driving, but you could be sitting on a ticking timebomb...get it checked out, and either junk the car if it needs a new tranny, or drop the $2500 for a rebuilt.