Anyone had Fendt 7-Series 4x4 issues?

[Rob Graham]

This isn't an excuse-making post...honest

Acquired a 2500g slurry tanker with 800 tyres and have it on an S4 718, now conditions aren't perfect but have picked and chosen where to go (using the pickup test followed by the walk test)
On 4 occasions now I've made quite a mess suddenly, all travelling well and within 3 seconds you can feel the rear of the tractor really lug down, and I mean 3 seconds, look round and front wheels are making no contribution despite 4x4 and diff lock engaged (not auto) These are on slight inclines, but when trying to back out straight the rear axle is doing all the work. Yet the front axle is engaging at certain times, definitely affects turning circle when on, enough to make me look like an idiot but I have a witness!

Or is it just the sheer weight and balance of the new larger tanker overwhelming the tractor? 718 with 870kg front weight weighs 8.5t, 2500g weighs 4.5t and 11.25t of slurry approximately
(old 2000g weighed 2.7t and 9t slurry)

Or is there something slipping possibly in front axle?

 

[melted welly]

This isn't an excuse-making post...honest

Acquired a 2500g slurry tanker with 800 tyres and have it on an S4 718, now conditions aren't perfect but have picked and chosen where to go (using the pickup test followed by the walk test)
On 4 occasions now I've made quite a mess suddenly, all travelling well and within 3 seconds you can feel the rear of the tractor really lug down, and I mean 3 seconds, look round and front wheels are making no contribution despite 4x4 and diff lock engaged (not auto) These are on slight inclines, but when trying to back out straight the rear axle is doing all the work. Yet the front axle is engaging at certain times, definitely affects turning circle when on, enough to make me look like an idiot but I have a witness!

Or is it just the sheer weight and balance of the new larger tanker overwhelming the tractor? 718 with 870kg front weight weighs 8.5t, 2500g weighs 4.5t and 11.25t of slurry approximately
(old 2000g weighed 2.7t and 9t slurry)

Or is there something slipping possibly in front axle?

sounds like you’ve got it in auto 4wd, it disengages if steering passes a certain angle.

edit. Sorry reread your post I’ve no idea!

 

[Rob Graham]

sounds like you’ve got it in auto 4wd, it disengages if steering passes a certain angle.

edit. Sorry reread your post I’ve no idea!

No worries, checked and triple checked I was engaging the right buttons and the dash was lighting up correctly, will jack and chock all up and check for any issues tomorrow

 

[icanshootwell]

I would imagine if the 4x4 was coming in and out or not constant the tractor should be showing some fault codes, no other idea really other than try diff lock and see if that makes any difference.

 

[melted welly]

No worries, checked and triple checked I was engaging the right buttons and the dash was lighting up correctly, will jack and chock all up and check for any issues tomorrow

There’s not been anyone playing with headland management has there?

 

[melted welly]

And if any help, on 828, the default 4wd state is ON ie if there’s a solenoid problem it’s in 4wd constantly

 

[Rob Graham]

I would imagine if the 4x4 was coming in and out or not constant the tractor should be showing some fault codes, no other idea really other than try diff lock and see if that makes any difference.

On last occasion came to an abrupt halt, knocked diff lock off and back on and still nothing, ensuring wheels were dead bloody straight, outcome being had to steer back and forward out of it...and again default issues would mean 4wd or diff being constantly on, certainly the rear wheels are doing 90% of the work to a different extent than the fronts which is why I think it might be mechanical somehow

 

[daveydiesel1]

On the road when braking at high speed does she make the whiney noise when 4wd engages?

 

[GFA]

Know of a 724 that needed a new 4wd clutch pack as it was slipping under load

 

[Rob Graham]

On the road when braking at high speed does she make the whiney noise when 4wd engages?

Having had brake issues with MFs in the past and having the exhaust brake on the Fendt I genuinely would rarely brake at any speed that made 4wd whine noticeable, and if I understand correctly on a Fendt braking doesn't necessarily 'engage' 4wd, if someone informed could correct that!

 

[Rob Graham]

Know of a 724 that needed a new 4wd clutch pack as it was slipping under load

Tbh something like this sounds plausible, you can hear the Vario groan as it loads up and then breaks traction from the rear, I used the varying I-IV settings to feather in or indeed sharpen the uptake of transmission and possibly traction but to no avail

 

[Mur Huwcun]

Having had brake issues with MFs in the past and having the exhaust brake on the Fendt I genuinely would rarely brake at any speed that made 4wd whine noticeable, and if I understand correctly on a Fendt braking doesn't necessarily 'engage' 4wd, if someone informed could correct that!

I don’t think they engage 4wd either as the cardan brake is in front of the 4wd pack

 

[dusty]

I had this problem a few years ago on a 724 was struggling to get up a hill on ploughing with the lime spreader then came to a stop when I noticed it was just the back wheels that was digging a hole. Done something similar a few other times then never had a problem again. Had plenty bother with the solenoids and the 4 wd defaulting to on constant as well so couldn’t blame anything along those lines

 

[Speedstar]

This isn't an excuse-making post...honest

Acquired a 2500g slurry tanker with 800 tyres and have it on an S4 718, now conditions aren't perfect but have picked and chosen where to go (using the pickup test followed by the walk test)
On 4 occasions now I've made quite a mess suddenly, all travelling well and within 3 seconds you can feel the rear of the tractor really lug down, and I mean 3 seconds, look round and front wheels are making no contribution despite 4x4 and diff lock engaged (not auto) These are on slight inclines, but when trying to back out straight the rear axle is doing all the work. Yet the front axle is engaging at certain times, definitely affects turning circle when on, enough to make me look like an idiot but I have a witness!

Or is it just the sheer weight and balance of the new larger tanker overwhelming the tractor? 718 with 870kg front weight weighs 8.5t, 2500g weighs 4.5t and 11.25t of slurry approximately
(old 2000g weighed 2.7t and 9t slurry)

Or is there something slipping possibly in front axle?

4WD solenoid valve will be full of water & not working , common fault on the early S4 ,light comes on but it will not be working , new ones have a better water seal.