G56 1st to 2nd grind

[Hercules130]

I noticed when i shift from low gear to 2nd when driving hard, it grinds a little. if i am just shifting while driving easy it is smooth. it is not a huge problem but it is something i don't think it should be doing. i only drive hard sometimes for a little thrill, even though this thing is a slug i still love it.

 

[john3976]

I noticed when i shift from low gear to 2nd when driving hard, it grinds a little. if i am just shifting while driving easy it is smooth. it is not a huge problem but it is something i don't think it should be doing. i only drive hard sometimes for a little thrill, even though this thing is a slug i still love it.

It was not designed to be a racing transmission, it was designed to pull heavy loads.



Speed shifting will never be its bright spot.

 

[klenger]

Are you actually launching in 1st gear empty? The only time I use 1st, other than towing is if I want to go real slooooow. I suspect your transmission is working normally. Enjoy.

 

[Buffalo]

Hi Klenger,



If I'm not mistaken, I believe that I read, here, that Peter from Southbend Clutch highly recommended starting off in 1st gear, always. I believe he thought it would extend the life of the clutch by quite a bit.



However, when I start in 1st gear, leaving a stop light, I am slower than everyone else. I almost always start in 1st gear and shift a 2000 rpm's.



4th Gear seems to be where the truck starts really picking up speed. That's where I start catching-up with the others. I've got the 3:73 rearend.



Joe F. (Buffalo)

 

[klenger]

While I am in no position to debate clutch life issues with Peter, it seems to me that shifting fewer times would increase clutch life (assumng you are not heavily loaded of course). As you have noticed, launching in 1st allows all the traffic to pass you. I usually launch in 2nd, and shift at around 1800. I get over 19 MPG local commuting using this technique.

 

[Gary - K7GLD]

Sometimes, the tendency to grind from one gear to another seems to relate to the inner structure of the gears/shafts. The previous NV-5600 tended to sometimes grind from 2nd to 3rd - and maybe from 3rd to 4th. I could be wrong, (surely NOT! ), but I think 2nd and 4th gears - maybe 6th too - are on a different shaft than 1st 3rd and 5th, which may put a bit more stress on syncros in matching gear speeds during shifting, especially if rushed.

 

[Hercules130]

Just to clarify, i am not speedshifting. if i start off in first at full throttle it might go to 2500 rpm and not build any boost, and then i go into second and chirp the tires, then into third it will chirp again. it doesn't usually build boost until 3rd. only when i drive like this it will grind a little on the 1-2 shift. maybe it is still just breaking in.

 

[Buffalo]

Klenger,



You've got a good point!!!



You're, also, putting extra stress by activating the clutch system more often.



I know I sure do see a lot of tail lights when starting off in 1st gear.



Joe F. (Buffalo)

 

[macdaddy]

1/4 mile?

Just to clarify, i am not speedshifting. if i start off in first at full throttle it might go to 2500 rpm and not build any boost, and then i go into second and chirp the tires, then into third it will chirp again. it doesn't usually build boost until 3rd. only when i drive like this it will grind a little on the 1-2 shift. maybe it is still just breaking in.

Shifting fast enough to chirp the tires with a CTD . Any manual is going to grind when your working it like a Muncie . Keep in mind the size of all those gears in there, each shift your demanding all of em to get in line with each other and integrate. If any thing we can count on you to clue us in on the 1/4 mile test



Mac

 

[Joseph Donnelly]

I believe Peter meant that if you have to slip the clutch much to start in 2nd (like if you have huge tires or a heavy lod/trailer), you are better off starting in first. Empty, with stock tires, 2nd gear starts are fine.

Going from "creeper" to the next gear (second, if you call creeper first gear and not low) is perhaps the hardest on the synchros if you shift fast or hard.

 

[klenger]

Joe: I totally agree with your statement.

 

[EMD-Run8]

Are you guys serious? These things will take off in 3rd with NO throttle. Granny Lo is for starting when loaded----and I mean LOADED, not when your taking a few bags of garbage to the local landfill. I might use 1st in the drive-thru line but when it takes off in 2nd and the tach needle doesn't even move, then there's no point in going any lower than that!

 

[6 2 Carl]

Just to clarify, i am not speedshifting. if i start off in first at full throttle it might go to 2500 rpm and not build any boost, and then i go into second and chirp the tires, then into third it will chirp again. it doesn't usually build boost until 3rd. only when i drive like this it will grind a little on the 1-2 shift. maybe it is still just breaking in.

First gear is just to get the load going, you should shift to second as soon as posible ie @1000-1500 rpm. If you are going up to 2500 rpm, that will be the cause of the grind.



If you are tring to race starting out in first gear, you will loose everytime. When I race I like to rev the engine up to 1800-2000 rpm, take off in second gear riding the clutch a bit to control wheelspin and keeping the rpms up around 2000rpm. I shift @ 3000rpm chirping the tires on the 2-3 shift, and 3-4 shift



Carl

 

[nickleinonen]

Shifting fast enough to chirp the tires with a CTD

if i am racing, it's not hard to do... [and i got 315's and 3. 73's under her]

 

[Hohn]

Since we seem to be debating driving technique, I'll submit my input:



I don't think that the synchros have that hard of a job to do if the RPMs are mostly matched when shifting. This means that your shift timing is crucial. You want the RPMs to be synchronized with the next gear to avoid the clutch having to absorb the speed differential. The synchros themselves will be fine if you 1) match rpms and 2) give them time to do their job.



I often start in first gear. I find that the extra shift involves less wear and tear on the clutch's friction material, at the cost of increased wear on the synchros and and throwout mechanism. I believe that the TOTAL amount of clutch slipping is less with a 1st launch, shift to second compared to a 2nd-gear launch.



My stock clutch is still holding power that it shouldn't be, even when the load dyno put the hurt to it. Maybe there's something to my reasoning? Or maybe I'm just lucky?



That said, I have the NV5600, which has a slightly taller 1st gear than the G56 does. If I had a G56, I might start in second, too.



As it is now, if I'm starting from a dead stop, I launch in first. If I'm able to start from a slow roll, then I start in 2nd.



I have the 3. 54s, so this makes it less painful to start in first. Once I get the 315s on, it will be PERFECT to start in 1st. Then I'll have a better launching gear AND a taller OD on the hwy-- perfect for my non-towing usage.



jlh