overdrive woes

[reed1285]

so today when i made a 40 mile commute to my hunting lease, my runner did not engage into overdrive a single time on the interstate. I ran a cool 55 the whole way there because at 55 i was turning 3100 rpm. I raced the engine up to about 4k rpm ( 60-65mph) and held it there for about 30 seconds and nothing, still no overdrive. However, about 15 miles away from my lease, I have to drive up a mountain. While going up the mountain it did kick into overdrive, but once I leveled out on top of the mountain and drove another 5 miles or so it went out of overdrive and didnt go back in the rest of the way there.

On the way home, it didnt go into overdrive NOT A SINGLE time. Not on the interstate or anywhere else.

Any ideas on what would be causing this? Is there a switch somewhere that wont let OD engage until a certain temp or something? I did a little research and that seems to be brought up quite a bit. It was cold today and I dont think my runner got up to normal operating temp until i started up that mountain. I know on the way home the temp gauge never read up to normal temp. Could this be my problem? if so i will just cover half the radiator with cardboard in the cold months to help it reach normal driving temp.

Ideas?

 

[CodeButcher]

I'm assuming the OD OFF light comes on.

This is a shot in the dark, you might want to check your Tranny fluid level. OD is controlled by a solienoid on the transmission, at least it is on my 2WD PU. There is a trick to leave it in OD, but that's if the solienoid does not work at all, but you stated it cam on while driving an incline, which leads to Tranny Fluid. I could be wrong, but it won't hurt any to check.

 

[KidVermicious]

I'm assuming the OD OFF light comes on.

This is a shot in the dark, you might want to check your Tranny fluid level. OD is controlled by a solienoid on the transmission, at least it is on my 2WD PU. There is a trick to leave it in OD, but that's if the solienoid does not work at all, but you stated it cam on while driving an incline, which leads to Tranny Fluid. I could be wrong, but it won't hurt any to check.

Exactly my first thought as well.

 

[reed1285]

Yeah apparently the switch works cause when i push it it says od off. Push it again and it goes out.

 

[reed1285]

Thanks for input. I checked the fluid in it about a week ago and it was fine, ill check it again tomorrow.

 

[fourwd1]

Could be the O/D solenoid going out, they become intermittent when they go bad.
Might be worth pulling it out and cleaning, might just be sticking.

 

[77'911]

You might change out the fluid completely, and set the level. This will probably help, as there is usually varnish or debris gumming up the solenoid.
regards

 

[fourwd1]

Is there a switch somewhere that wont let OD engage until a certain temp or something

Yes. The AT ECM won't allow O/D to work until the engine is up to temp.
A bad temp sensor or low coolant level could cause that.

 

[reed1285]

Yes. The AT ECM won't allow O/D to work until the engine is up to temp.
A bad temp sensor or low coolant level could cause that.

I guess your talking about the coolant temp sensor?

Thanks for all the input/advice so far!

 

[fourwd1]

I guess your talking about the coolant temp sensor?

Thanks for all the input/advice so far!

That would be correct, the one for the EFI and ECT ECMs, not the one for the dash gauge.

First step would be to check coolant level.

 

[reed1285]

Im bumping this old thread up with an update. I still havent resolved this issue, but now I know beyond any kind of doubt that its some kind of temp sensor/module screwed up thats keeping me from going into overdrive in the winter months. All of last summer when it was hot outside, I never had the first problem with it kicking into OD like it should. Just like last year though, when it started getting cold out, it quite doing it. During the cold winter months, my temp gauge needle never reads like it does when its hot out, unless i sit idling for a bit, or pull a mountain in it. So I need your guys' help. Is this temp sensor giving me this issue on the tranny? Or is it on the engine somewhere? Would I be better off taking it to a transmission shop, or is this something an average shadetree mechanic can handle? thanks

 

[Hyde802]

First step would be to check coolant level.

Did you check the coolant level?

 

[reed1285]

Did you check the coolant level?

yep coolant level is fine. After a bit of digging around ive found some people fixed this problem with a new/higher degree thermostat? or would it need a lower degree one?

 

[Hyde802]

You would need a hotter one.

If you heater was on full, it could be pulling too much heat out of the system.

Toyota 4Runner and Pickup: Cheap Tricks

Dont go by me though, not sure if this is the answer, but just something to look into

 

[541joseph]

Your Tstat could be stuck open causing this problem not letting it reach operating temp. That's where I would start.

 

[reed1285]

Your Tstat could be stuck open causing this problem not letting it reach operating temp. That's where I would start.

Thats what Im going to do, pop a new thermostat in it and go from there. I guess I'll get a hotter than stock one.

 

[541joseph]

I would go 10 over stock at most. A stock one should be fine if its working properly. Good luck.

 

[DeclansDaddy]

I've had the same problem with my 2nd gen. When it's super cold outside it won't shift into overdrive. When I got the truck the temp gauge barely moved off the C line when it was cold out and even on these rare 70 degree days it barely goes past the C. I put a new thermostat in thinking it was stuck or rusted through but that didn't help. Ended up sticking cardboard to the front of my radiator and that has seemed to help. I've seen truckers do it so I figured what the heck. Now temp gauge goes 1/4 way up and shifts into OD fine.

 

[reed1285]

Got a new thermostat, i got the hotter one. There were only two options at my Advanced Auto. A 180* and a 195*. Apparently the stock one is 180*, didnt know that. This should hopefully fix the problem. Im gonna put it in tomorrow. Ill update again when i get it done.

 

[reed1285]

Ok so get this. Unbeknownst to me, there wasn't even a thermostat in my 4runner! So there was my friggin problem this whole time :redbrick:

So in regards to that, I took the 195* thermostat back and switched it out for the stock 180*. I'm both happy that the problem was that obvious, but also a little worried why the previous owner wasn't running a thermostat. I'm hoping they were just too tight to go buy a new one when it went out. Time will tell I guess. I haven't actually drove it yet, going to in about an hour, but I let it idle for about 20 mns. It came up to temp fine, and didn't overheat. So that's good. Hopefully this matter is closed now!