Crawl box runs hot

[slander]

My trucks a DD with a 4.7:1 crawl box in it, and it runs hot. It heats up the shifters and i can feel it under the shift boot. Oil looks okay, not burnt or anything. Case does not leak, and it does not have an internal leak. It doesnt spew out of the vents either. I cant really get a pattern down, and cant tell if its just heat coming off the cat that right next to it or what. It gets hot about 5miles into my 30mile commute and stays at a constant temp, from what i can tell by touch. I have had it in for about a year now, and has done this since i put it in. How normal is this? My commute is mostly highway, 55-65mph.

[Wes]

My trucks a DD with a 4.7:1 crawl box in it, and it runs hot. It heats up the shifters and i can feel it under the shift boot. Oil looks okay, not burnt or anything. Case does not leak, and it does not have an internal leak. It doesnt spew out of the vents either. I cant really get a pattern down, and cant tell if its just heat coming off the cat that right next to it or what. It gets hot about 5miles into my 30mile commute and stays at a constant temp, from what i can tell by touch. I have had it in for about a year now, and has done this since i put it in. How normal is this? My commute is mostly highway, 55-65mph.

Road heat. If you drive on dark asphalt roads during the day it is going to heat up. If it does it at night too- then something might be wrong. Otherwise, just deal with it.

[Toyasaurus]

Have you tried a heat shield inbetween the cat and the crawl box?

[SAR_Squid79]

My Inchworm case does this too. When I first put it in, I was really worried about it . . . but it's been over 2 years now. Apparently it's not a big problem.

[Winch]

It is most likely due to the modifications you did to the shifter boots. Mine was running hot as well, until I figured out that it had everything to do with airflow around the T-cases. I used some rubber sheets and gasket sealer to seal the floor around the shifters properly, the way it used to be. I believe that the reason why this helped has to do with airflow around the cases. If there is a gap in the floor, hot air will be forced upwards and into the cab. You should notice that this is especially bad when you have a window open. If you close your windows, it creates a bit of pressure in the cab, causing the air to flow backwards around the cases the way it should, keeping them cool. Give it a shot.

[slander]

Wes: It did the same thing in the winter and at night so i dont believeits road heat.

I will try the heat sheild, and i do have a bit of a gap around the sheet metal and the shifter. Its mostly the shifter it self getting hot, but there is heat coming in around the gaps as well.

[RaideRNatioN]

Mine does it too. Its normal, there are several gears and bearings in there that mesh and turn creating heat. Its like a tranny minus a clutch....gears and bearings that creat heat. Its all good.

[hytenor]

My trucks a DD with a 4.7:1 crawl box in it, and it runs hot. It heats up the shifters and i can feel it under the shift boot. Oil looks okay, not burnt or anything. Case does not leak, and it does not have an internal leak. It doesnt spew out of the vents either. I cant really get a pattern down, and cant tell if its just heat coming off the cat that right next to it or what. It gets hot about 5miles into my 30mile commute and stays at a constant temp, from what i can tell by touch. I have had it in for about a year now, and has done this since i put it in. How normal is this? My commute is mostly highway, 55-65mph.

you need to define "hot" ;) pick up one of those cheap lazar thermometers and find out. HF has them for either $6 or under $30 (higher temp reading).
Mine runs around 160 or so in the summer on long trips and I've gotten readings over 180*. my shifters, both crawler and tranny, get quite warm on the shafts. I have an Inchworm knob on the crawler and it gets warm as well but not hot.
Do you have any skids? they will trap a lot of heat up in there but not enough to be a problem.

you might try a different oil if you are concerned. I do not recommend the thin synthetics, however ;)

[slander]

you need to define "hot" ;) pick up one of those cheap lazar thermometers and find out. HF has them for either $6 or under $30 (higher temp reading).
Mine runs around 160 or so in the summer on long trips and I've gotten readings over 180*. my shifters, both crawler and tranny, get quite warm on the shafts. I have an Inchworm knob on the crawler and it gets warm as well but not hot.
Do you have any skids? they will trap a lot of heat up in there but not enough to be a problem.

you might try a different oil if you are concerned. I do not recommend the thin synthetics, however ;)


What oil weight do you run in yours?

[hytenor]

What oil weight do you run in yours?

85/90, Valvoline standard gear oil right now. (what Jim suggests) I did try running some Redline Shock Proof (blue) but it didn't seem to effect the temp enough to justify the extra price.

[Winch]

Mine does it too. Its normal, there are several gears and bearings in there that mesh and turn creating heat. Its like a tranny minus a clutch....gears and bearings that creat heat. Its all good.

I don't agree with this. If it was normal, as you suggest, why don't you see the shifters on new or stock trucks get hot? They only get hot, once you start messing with the shifter boots, because you disturb the airflow around them. Once you restore the seal around the shifters, they should run a lot cooler.

[NorcalPR]

Mine get hot. I have the Inchworm sealed shifter, with the knob, and on long drives, especially towing/hauling, I can grab the knob, and it's hot, but not like "burn yourself" hot.

-P

[Mr Tacomi]

85/90, Valvoline standard gear oil right now. (what Jim suggests) I did try running some Redline Shock Proof (blue) but it didn't seem to effect the temp enough to justify the extra price.

I have proven to myself *twice* that Valvoline gear oil is about as low grade as it gets. I use it as break in oil (because every local parts story seems to only carry it); but put synthetic in for long term--again proven to myself the less friction & wear the synthetics provide for one, but the ability to handle the higher temps if I were to be putting extra stress on something out of the ordinary.

[SAR_Squid79]

I don't agree with this. If it was normal, as you suggest, why don't you see the shifters on new or stock trucks get hot?

Because crawl boxes are gear driven. Stock cases are belt driven.

[NorcalPR]

I have proven to myself *twice* that Valvoline gear oil is about as low grade as it gets. I use it as break in oil (because every local parts story seems to only carry it); but put synthetic in for long term--again proven to myself the less friction & wear the synthetics provide for one, but the ability to handle the higher temps if I were to be putting extra stress on something out of the ordinary.

I've had great sucess with the Lucas oil (not the additive). When I had my floorboard open and you could hear every little noise whether you wanted to or not, the Lucas actually quieted down the case considerably.

[slander]

I don't agree with this. If it was normal, as you suggest, why don't you see the shifters on new or stock trucks get hot? They only get hot, once you start messing with the shifter boots, because you disturb the airflow around them. Once you restore the seal around the shifters, they should run a lot cooler.

I dont know how much air flow you can manipulate with shifter boots. Im sure thats not a high wind area anyway up in the tranny tunnel, with the cat 3 inchs from the side of the box, with a skid plate and the engine and tranny infront of it. After my tear down i have concluded my heat may have been from a 1) bearing that had some crap in it and was running rough 2) some RTV was splooged into the oil channel on the adapter and blocking most of the oil going into and around the bearing to lubricate and dissapate some of the heat, and 3) my failing coupler and input shaft.

[Winch]

Because crawl boxes are gear driven. Stock cases are belt driven.

Maybe in Tacomas, but when was the last time you jumped into a mini truck or 4Runner that came stock with a gear driven case? Did they run hot from the factory?

[NorCalTaco]

My inchworm always ran "hot"

I would not worry about it.

As stated before if you dont like the extra heat in the cab figure out a way to insulate that area better