Engine/Transmission (1998.5 - 2002) shifting to 6th and lsd

[TIngram]

when i shift to 6 in my truck if i shift fast tere is a grind but if i pause for a second in neutral and then shift to 6 it is fine. a friend of mines truck did the same is this normal if so then why is 6 not syncronized? also differential will only spin one tire it is supposed to be a limited slip according to teh window sticker what could be wrong?

thanks tad

 

[RustyJC]

6th gear is synchronized, but if you shift too fast, you can beat the synchro's balk ring and grind the synchro teeth due to the high rotating mass of the gears, clutch disk, etc. Once in a great while I notice a little grind going into 3rd, even at 16,700 miles, but I've never noticed it going into 6th. Of course, I don't try to shift the NV5600 like it's a Ford T&C top loader with a Hurst Competition Plus, either. If you bought the truck used, the previous owner might have the wrong lubricant in the transmission as well.



On the LSD, the "tightness" of these things vary all over the map from truck to truck. If it's not worn out (you don't mention how many miles are on your truck), it may have too much friction modifier in the rear axle lubricant - that means it won't chatter on a turn, but it won't function properly, either.



Rusty

 

[TIngram]

sorry that i didnt put the miles the truck has over 102000 on it normally i shift it slow but sometimes on the interstate racin of coure i like to grab er fast but i undersatnd as far a the rearend what should i put in it. well the rear end and transmission what oils should i use. thanks alot

tad

 

[Hohn]

As usual, Rusty is dead on the money. The vast majority of the factory LSD have way too much modifier in them.



DC wanted to favor drivability, so the went a little towards the loose end on the diff tuning. Just swapping the lube should fix that if the clutches are still there.



Justin

 

[DSteinel]

The Amsoil that I put in mine works great with no modifier needed.