Abnormal manual transmission heat?

Hi Guys,
I’m a long time reader first time writer so there is a good chance that this is posted in the wrong place.
So, I’m the third owner of a 5 speed 1998 tacoma 4X4 Xtracab Limited with 165k miles on it. It’s one hell of a good looking truck, but I think it was neglected in the fluids department (story for another time).
I noticed when I was driving it the other day that the shifter knob was warm and the metal shaft part of the shifter was even warmer. I went under the truck and checked the transmission casing's temperature and it was hot like touching part of the engine hot. I also noticed the transmission casing was scaly with many surface cracks it that looked the metal was really hot then cooled really quickly. See picture.

I changed the transmission gear oil and used the recommended API GL-5

$30 75W 90 Synthetic Gear Lube - 1 Quart (Pack of 2)

75W 90 synthetic oil. The old transmission oil looked like metallic paint there was a lot of small yellow fine particles in the oil. But I figured that this oil has probably never been changed so if I kind of expected it.

I’m still having the same problem after about 30-45 minutes of driving the stick shift starts to warm up and transmission casing is really hot.
Is it normal for a manual transmission to generate this much heat? Any other thoughts?
Thanks guys,
Ryan

 

I think it is probably normal, unless you have an exhaust leak blowing on it. The pipe and cat are right next to the tranny, and these radiate a shitload of heat anyway. I can't say that I've noticed my stick getting as hot as you mention, but this is a subjective thing.

The condition of your tranny oil was most troubling. I think if it looked that bad, I would have opted to just run some non-synthetic through it for a short period to get out more crap and clean it up a bit, then change again with synth.

these things are built to last, so I wouldn't lose too much sleep over it unless you actually start having issues with shifting.

 

I've never noticed my m/t get real hot before so I'm not sure how normal that is. The yellow particles doesn't sound good. Also you don't want the GL-5 in the m/ts on these trucks. The only m/t fluid I've found that doesn't have the GL-5 on it was Redline MT-90 and possibly amsoil.

 

^^^^^ This

I think I read that GL-5 has components that can break down some of the metals in the tranny. Redline MTL or MT90 are excellent GL-4 choices.

The sychros are brass I think, a yellow metal.

 

You know, I keep hearing this GL5 business, but the owner's manual does in fact say GL5 or GL4. Has anyone seen some definitive explanation of this GL5-is-bad-for-these-trucks theory?

Ben? Where are you, Ben? Beuller? Allan? Steve?

BTW, I am running MT90 too...

 

I've noticed the shaft of my shift lever getting hot on occasion. Usually it gets warm after driving for a bit. If I'm doing 75-80 on the highway for a stretch it can get hot, like I don't want to hold my finger against it hot, but I can without getting burnt or anything. I think it's normal.

 

I have noticed that mine as gets hot. I changed the fluid and the old fluid was in good condition, and it is still warm on the shifter.

If you had a lot of yellow metal in the oil that is what the syncros are made of... Does it shift hard, grind, pop out of gear? Is so you may be looking at a tranny rebuild.

If it still shifts smooth and is only warm to the touch your probably fine, looks like a lot of peoples are warm without aany problems.

 

My 98' got really hot, and my new to me 2002 gets smokin' hot. I can actually feel hot air coming out of the collar of the shift cover after driving it a while. I'm told it's pretty normal. Hope this helps.

 

Hey Guys,
Thanks for all the comments. Looks like this is nothing for me to worry about. I think I'll change the transmission fluid in the near future to something better quality and go the GL-4 route (If I can find some). I don't want to start the GL-4 GL-5 debate it's been done to death.
Thanks again everyone.

 

I looked and the GL-4 is tough to find, best bet may be an amsoil dealer.

 

$24 Red Line (50304) MT-90 75W-90 GL-4 Manual Transmission and Transaxle Lubricant - 1 Quart

http://www.amazon.com/Red-Line-50304-Manual-Transmission/dp/B000CPCBEQ

 

I found the Redline at a local performance-oriented auto-parts store (for anyone in Sac, Tognotti's).

Perhaps the Redline website has dealer locator info? Likewise for Amsoil?

 

I found Redline at Jegs

 

When I was putting my new headers on my truck. I noticed similar surface cracks on my transmission... is this normal?

 

Even without the internal friction generating heat, the mtx will get hot simply because it is thermally linked to the engine. Like the handle of a cast iron skillet.

 

Yeah, nice analogy! It is basically a heat sink...

 

Yeah it's too bad I'm in Canada, Amazon doesn't seem to be able to ship anything that i want this gear oil included.

 

Good excuse to come south for a visit to Bellingham. Check out the Carquest Auto parts store there. I'll bet they will have the Redline Oil products on their shelves. The store in Renton does, so they will at least be able to get if for you if they don't have it.

http://national.citysearch.com/profile/10822943/bellingham_wa/carquest_auto_parts.html

 

I don't have Tacoma but a 96 Toyota 4runner. My gear shift shaft would get very hot while driving. Hot enough that I didn't want to keep my hand on it too long. The other day I replaced my gear oil and while driving today I noticed that the gear shift shaft was luke warm at best. It's got to be the new oil protecting the gears and keeping the friction to a minimum. I used Sta-Lube 85-90 gl-4 from Napa Auto Parts. One gallon was $35+tx. It seems to be a bit thick especially in the winter. Takes 1-2 miles of driving to heat up the oil and then it shifts easy. Starting off with something a little thicker than what's recommend will probably make it last longer before next change. I will keep my eye on the temperature of the stick, it may be an indication when I need to replace oil. No synthetic oils for me, all conventional and mileage is at 404,000.