TN70A 4WD working?

[Doc_Bob]

How do i know if my FWD assist is working? I have noticed that when I engage my FWD that I can spin the rear tires and have the front remain still.
Bob

 

[jimmysisson]

How about raise the front end with the loader bucket, tractor stopped. Engage reverse and back up a bit in 4wd, see if the fronts rotate without touching the ground?
Jim

 

[jinman]

How do i know if my FWD assist is working? I have noticed that when I engage my FWD that I can spin the rear tires and have the front remain still.
Bob

Unless you have a locking front differential, only one front wheel will spin. I can tell two ways on my tractor. With a full bucket, if I try to back up a hill without MFWD engaged, the rears will spin. An easier way is to disengage MFWD and use differential braking to turn. Engage MFWD and try again. If it is much harder, then MFWD is working.

 

[Doc_Bob]

How about raise the front end with the loader bucket, tractor stopped. Engage reverse and back up a bit in 4wd, see if the fronts rotate without touching the ground?
Jim

I did exactly as you suggested. Front wheels turn when 4WD engaged, and stop turning when 4WD is disengaged.

Bob

 

[PineRidge]

Looks to me like you answered your own question Bob. Glad it's working the way it's supposed to.

 

[Doc_Bob]

Looks to me like you answered your own question Bob. Glad it's working the way it's supposed to.

Mike, it appears to be working as advertised. I think I have figured out that my TN does not really have a traditional 4WD, but something like a part time FWD assist.
Bob

 

[PineRidge]

Bob I don't think there are many subs that actually drive all 4 wheels at the same time.

 

[Robert_in_NY]

Almost all 2wd based tractors are Front Wheel Assist setups (FWA). Very few have an actual 4wd system and this is true for tractors of all sizes until you get into the 300 horse articulated tractors and bigger.

 

[Doc_Bob]

Almost all 2wd based tractors are Front Wheel Assist setups (FWA). Very few have an actual 4wd system and this is true for tractors of all sizes until you get into the 300 horse articulated tractors and bigger.

FWA? So how is it different from 4WD?
Bob

 

[dgl24087]

In FWA (front wheel assist), the front wheels engage when rear wheel slippage occurs. 4WD is constant engagement of the front drive wheels.