TB42. How many revs are too many when towing?

[ripper]

I'm trying to work out how fast I should drive when heavy towing.
Obviously safety is the first thing to take into account, but engine revs are my next concern.
Will a TB42 happily sit on 2500 revs all day?
I wonder because in OD it's only doing about 1800 revs at 100km/h, and an extra 700 revs seems like a lot to expect it to take constantly.
Thanks.

[Silver]

G'day Ripper,

The TB42 bore and stroke are the same - which usually means a motor that likes to rev. Contrast motors where the stroke is longer than the bore - more torque.

I guess the fuel consumption would go from high to very high :-)

I noticed you said heavy towing - I would think about whether this is a good idea in 5th gear, where the gears and shafts are smaller.

I would be inclined to keep it within the yellow marked rev range on the tacho, most of the time

[ripper]

I noticed you said heavy towing - I would think about whether this is a good idea in 5th gear, where the gears and shafts are smaller.

Thanks for that. Our Trol is an auto, so no 5th gear
Wanting to avoid overloading the OD is what started this issue of how many revs it will happily keep doing.

[taslucas]

Having OD it would be an auto? The TB42 tacho has yellow between 2 and 3000 rpm with I take as being the power zone. I think the biggest danger is over heating the auto. An aftermarket oil cooler can be fitted to help keep temps down

tappin it

[pearcey]

G`day Ripper
Check your manual and see where the motor has max toque and drive to that rev range. It will also give you your best economy in that area.

[taslucas]

Thanks for that. Our Trol is an auto, so no 5th gear
Wanting to avoid overloading the OD is what started this issue of how many revs it will happily keep doing.

OD isn't another gear. It's a solenoid that locks the torque converter so the drive goes strait thru the box. (this is my lamens terms lol)

tappin it

[ripper]

G`day Ripper
Check your manual and see where the motor has max toque and drive to that rev range. It will also give you your best economy in that area.

Yeah, I wish I had an owners manual. I've got a workshop manual, but haven't found what I need in it.

OD isn't another gear. It's a solenoid that locks the torque converter so the drive goes strait thru the box. (this is my lamens terms lol)

tappin it

Actually OD and the torque converter lock up are two separate parts of the tranny.
When it's working properly, you can watch the tacho drop when you put it into overdrive, and then about 90km/h it'll drop again when the TC locks up.

[taslucas]

Yeah, I wish I had an owners manual. I've got a workshop manual, but haven't found what I need in it.



Actually OD and the torque converter lock up are two separate parts if the tranny.
When it's working properly, you can watch the tacho drop when you put it into overdrive, and then about 90km/h it'll drop again when the TC locks up.

Ahhh... See I only have the power button in mine. With the power button OFF, the box changes up through the gears till it's in top gear then when you reach around 90km/h the lock up solenoid kicks in. If I let it change up to top gear (but before the lockup kicks in) then push the power button to ON, it kicks back a gear.
So driving with the OD off, is the same a driving with the power button on (except the computer lets the years rev out a bit more before changing)
Because I don't have an OD button doesn't mean I have one less gear.



tappin it

[ripper]

Yeah, I'm talking about the power button. It can't go into OD if you've got the power button on.
From what I've read, newer Patrols have two buttons for auto options.

[Clunk]

Yeah, I'm talking about the power button. It can't go into OD if you've got the power button on.
From what I've read, newer Patrols have two buttons for auto options.

I've got the power switch on me dash and od button on the gear stick. With the power button on, it still goes into od but just revs higher and holds onto the gears longer as im increasing speed....... oh its a 94 GQ auto