6 sp. Mt

Ive got a 2008 sr5 6speed mt.
My question is, can I use the 6th gear when towing my ~3500lb trailer?
I know not to use it on big hills, but straightaway etc Ok?
On mt you shouldn't use the od, that's why I ask.

 

I do, depending on the terrain. If I'm on the open highway with no headwinds and not pulling too hard I find there is no ill effect to drop it into 6th. If I start a small incline I just gear down and all is fine.
I'm towing a 3200 lb RPOD for reference.

 

Well, yes you can tow in OD. It is just another gear. Nothing special about it. In my 2016 both 6th and 5th are overdrive gears. Top gear works for me when I'm on mostly level ground and not fighting a head wind. My trailer is 3900 lbs dry.

If your truck lugs down, can't keep speed, then downshift. Pretty simple. If it can maintain speed and you don't have your foot to the floor you're probably good to go in that gear even if it is 6th.

EDIT: I suppose there is a chance to overdrive gears are weaker and that may be the reason to avoid towing in OD. I have a tough time believing it however, but there ya go.

 

Not arguing, but rather asking. Do manual transmissions have overdrive? And if so, does it matter if he tows in 6th gear? My point is, I thought (and could very well be wrong) that with manual transmissions that you didn't have to worry about heat like you do with automatics since they don't "hunt" for gears. I am relatively new to towing, and still learning.

 

I'm no expert, but to my understanding "overdrive" is just referring to gears that have a ratio of less than 1:1. In both the MT and AT, 4th gear is a 1:1 ratio and both 5th and 6th are overdrive ratios; 0.85 & 0.71 MT and 0.69 & 0.58 AT respectively.

I can see only 3 possible reasons to avoid using the OD gears:

1. Not enough torque to maintain speed: If you find your AT is frequently going between 6 and 5 then put it in 5th and leave it there. If you have no throttle response or are losing speed with the MT, downshift to the next lower gear.
2. Heat: The AT may run cooler in the next lower gear. I think this doesn't apply in the same way to the MT.
3. Weak gears: Could it be that the physical gears that achieve the overdrive ratio are also inherently weaker? I find it hard to believe, but perhaps.

What I do with my MT is to live mostly by rule 1. If I don't have the power to maintain speed I downshift. With my ~4000 lb trailer that means I can run 6th on flat ground with no significant headwind. If I come to a small hill, I need to anticipate it and downshift to 5th or 4th. If I shift back to 6th and can't maintain speed, back into 5th it goes.

 

I guess my point was that there is no need to "worry" about what gear you are in when using a MT. If it isn't enough power, then downshift. Unlike AT where the heat will destroy the AT.

 

Bingo. (IMHO)

 

Thanks to all. Now I just need to add an oil cooler.

 

Engine oil or transmission oil? Why a cooler?

I just changed the fluid in my rear axle and transmission to synthetic so it would work better while towing (better heat tolerance). That was easy. Adding a cooler? That sounds hard.

 

Why?

How do you know your oil is having a problem now?

If it's not needed, it just becomes another point of future maintenance/leak potential.

 

MT needs an engine oil cooler to tow. I'm using full synthetic engine oil now, because of the better heat tolerance. But I do plan long trips with the trailer, and don't want any unexpected problems.

 

How do you know? I thought the engine has no oil cooler when it is coupled to an AT, why would it need one when coupled to an MT?

With a 3500 lb trailer I would be shocked if an engine oil cooler was needed. More than shocked I'd be worried.

 

and again I ask........

Not trying to say you don't, or be argumentative, just trying to understand how you've reached this conclusion.

 

It' in the towing bible, TW. Also on towing packages with MT.

 

Talking with my renowned mechanic,( not the stealership, they'd sell me anything they could). Asked about adding the oil cooler. He said don't bother, not needed, never seen one.

 

You can purchase oil coolers for manual transmissions . They are similar to a cooler for an automatic only they also come with a 12 volt pump to keep the fluid circulating . You can also add these coolers to transfer cases and differentials .
Grab a temp gun and measure your temperature while towing . If its under 225 , you are good to go

 

225? At the pan? 225 seems high to me. But I am not an expert

 

225 is far too high for an automatic .. 176 is ideal , a manual can handle 225 but anything hotter is questionable . That oil still breaks down in a manual transmission .

 

I get nervous when it hits 200 (automatic) on the out. My pan has never gone above 200

 

https://www.tacomaworld.com/threads/transmission-coolers.526283/