Thread: Stiff change when hot

Hmmmm. My lt95 does the same in 4th. Usually only in hot weather. Was contemplating an r380 replacement.

Originally Posted by 123rover50

I have recently bought a 200tdi with 180 thou up. When cold the lt77 changes nicely and synchro,s all work OK. Oil is Dexron 3.
As it gets hot the change gets stiffer and the change into 3rd starts to beat the synchro.
After a short rest say half hour, all is OK again for a bit.
Is this just a matter of wear and live with it or would a change of oils help?
I am tempted to try VMX or syntrans but thought perhaps they may make the synchros worse.
Can a cooler be fitted, that may help too.
Any ideas?

Didiman.

V8 boxes have a cooler, but I'd take the Dexron out of it and run GL4 gear oil. I always run Valvoline dura gear 75/80 in my car works fine, can get a little firm when really hot towing. My car is a 94 3.9 v8 with an LT77S box. Make sure you don't buy the Dura gear 90 GL5 diff oil, bottle looks the same. I've run this oil for 12 years