My old LT 1000 does that but it disappears after just a short use.
I wrote it off as a old worn, cracked drive belt.
The brake barely works on this old timer.
It's worth watching when the wife uses it..(I'am bad)

Wow, I'm impressed. If it is the same LT 10 I had with a Peerless 3 speed tranny and chain drive to a differential, your machine is still going after 30 years.

Tom is right about the brakes, I hope that helped. Another problem especially with older machines can be the condition of the pulley's and idlers, especially the engine pulley. The belt has to slip to a degree in that pulley in order to disengage the belt. Rust or wear in the pulley, or a badly worn belt where the clutching cover is exposed and the rubber is coming through to much, etc. may cause clutching to deteriorate. Other than new parts I've seen a little dry graphite slick things up and provide at least a temporary solution. You can buy it in a squirt can, often used to lubricate locks. Get it on the belt and pulleys and you will see a difference. Good luck.

tomplum -It is not the brake.
dynamike59-my belt is >15yrs maybe?
mrtractors- my LT10 is from the mid 70's; (it does not have a separate differential); it has the original 11HP briggs engine, does not burn oil and even though it has been abused, it has been virtually trouble free. I use it now mainly with the snowthrover attachment. I stopped regularly using the cutting deck because it cannot mulch and there is no bagger available - I have a lot of leaves in the fall.

I will try the graphite.

mrtractor - I did not have graphite spray but I did have silicone lubricant spray. I sprayed the belt while idleing in neutral and it worked like a charm!

Thanks!

Let us know when it starts to slip ;) !!!

And when you replace the belt, try to get a "wrapped" belt rather than a "raw edge" belt. Wrapped belts have better clutching action while raw edge belts tend to grip much quicker and have lots less clutching action. It's possible your belt is old enough to have worn the fabric wrapping off as someone stated above.

Good advice horsepen.

Wrapped belts are good for more horsepower. They are often referred to as OPE belts. The rubbers ones from the hardware store are for "fractional horsepower" applications though they will sometime work in a pinch (while you wait to the OPE belt to arrive).

I have an older model Cub Cadet that bucks terribly when taking off going forward but is smooth as silk in reverse. . There are no belts. Please help.

My 1020 JD will stand up because the clutch and breaks stick

Check the belt ,it's either it has a crack in both sides or the vacuum pump pulley base is not tightened firmly ... hope this helps

.. Engr Frank

i had same issue. brake was sticking. Some PB blaster on all the parts (not the pad and disc) loosened everything up. Brake no longer sticks, mower doesn’t jump forward anymore. Thanks everyone!