harsh downshift to 2nd

beached_titan · 08-10-2006, 09:26 AM

the other day iwas coming down a hill so i used my manual shift mode to downshift and engine brake my truck. i shifted down to 2nd at about 30mph and my truck shook so violently i thought my wheels were falling off or something. ive noticed slight vibration when shifting down to 2nd for a while now actually since ive had it lifted. but the other day was the first time that it shook the entire truck. so just wondering if anyone else has had this experience? maybe its because of the bigger tires? im running 35's on my truck... i dont know, im clueless. i want to take it in to the dealer but im afraid of getting the "well, its modified" speach again.

galaxycrew · 08-10-2006, 09:42 AM

no its me too. i guess it could be because of the larger tires, as i have 35's too

i've just gotten much more accustomed to downshifting to 2nd when going at a much slower speed (25-30mph).

beached_titan · 08-10-2006, 10:18 AM

wow, thats a comfort... i guess... ive never experienced anything like this in any other lifted truck. guess i just wont downshift to that gear lol

thanks for the reply

beached_titan · 08-14-2006, 03:55 PM

hmmm just from reading other posts, im thinkin this might also be axle wrap when im downshifting... any thoughts?

SOCALTITANKC4X4LE · 08-14-2006, 04:22 PM

This is no need to manually down shift to 2nd, unless you are going down hill and you are trying to prevent your brakes from heating up. And you are going 20 mph or less. Your truck shook because you shifted down too soon. From 4rth to 3rd, you won't feel it, but 3rd to 2nd is a big drop.

beached_titan · 08-14-2006, 05:16 PM

shifting down to 2nd at 30mph is too fast? it does it even worse at 27mph...
i dont think speed is the issue, the manual says that if the vehicle speed is too high for the gear being selected, then it will not downshift into that gear. i can shift down to 1st at 22mph and get no vibration at all.
and yes i need as much braking help as possible, this one section of a freeway here that i take home everyday has a 15% downgrade and traffic ALWAYS builds up at the bottom of the hill. being that i have 35's, i dont really feel like glazing and warping the hell out of my rotors.

edit: i see you live in riverside, so ill tell you. coming down the 241 to the 91 at 5:45pm. you know how traffic builds up on that hill all of a sudden. and if im cruising at 70mph and see brake lights, i start downshifting to slow this beast down!!

StuntDriver06 · 08-14-2006, 06:20 PM

Quote:

Originally Posted by beached_titan

shifting down to 2nd at 30mph is too fast? it does it even worse at 27mph...
i dont think speed is the issue, the manual says that if the vehicle speed is too high for the gear being selected, then it will not downshift into that gear. i can shift down to 1st at 22mph and get no vibration at all.
and yes i need as much braking help as possible, this one section of a freeway here that i take home everyday has a 15% downgrade and traffic ALWAYS builds up at the bottom of the hill. being that i have 35's, i dont really feel like glazing and warping the hell out of my rotors.

edit: i see you live in riverside, so ill tell you. coming down the 241 to the 91 at 5:45pm. you know how traffic builds up on that hill all of a sudden. and if im cruising at 70mph and see brake lights, i start downshifting to slow this beast down!!

its not too fast, the titan tranny brain is trying to make all shifts as smooth as possible, which it accomplishes by allowing slippage between the clutches between shifts... bigger tires, hills, higher heat can all play a factor as to how much slippage occurs, and the vibration you feel is most likely the clutches trying to engage....

SOCALTITANKC4X4LE · 08-14-2006, 09:01 PM

edit: i see you live in riverside, so ill tell you. coming down the 241 to the 91 at 5:45pm. you know how traffic builds up on that hill all of a sudden. and if im cruising at 70mph and see brake lights, i start downshifting to slow this beast down!![/quote]

I understand about the going downhill on the 241. I would just anticipate the slow down and just drive slower as you approach the 91. No matter what, you're going to have slow down, because you can't fight the traffic. Why put more load on your tranny and brakes?

galaxycrew · 08-14-2006, 09:33 PM

hey beached titan...what kind of lift do you have? i have the procomp stage1 with 35" bfg at's. i too have axle wrap, and yes this may be the cause of the vibration. i have had the carrier bearing drop kit installed, but this only slightly fixed the problem. to completely eliminate the axle wrap, i plan on a full deaver pack + prg traction bars.

Yellomantis · 08-14-2006, 10:54 PM

this was happening on my 04 that I had. It was bone stock though. It felt like the whole truck was juddering as it dropped into the lower gear. It never went away. I don't have the problem on my 06 as of yet. But I only have 3500 miles on it too.

*SilverQShip* · 08-14-2006, 11:37 PM

I've found a slighty different problem. The other day we were cruising at a reletively slow speed (50) and we had to get around this car so my dad kinda put the hammer down. THe revs got to 6200 rpm and there wasnt that much of a pull but on the upshift it felt like we got rearended. THe truck reared and took off.

-Son fo SQS

beached_titan · 08-15-2006, 07:20 AM

Quote:

Originally Posted by StuntDriver06

and the vibration you feel is most likely the clutches trying to engage....

possible, but when it literally feels like the transmission just dropped out the bottom of the truck i kind of get the feeling its more than clutches trying to engage

it never did it until i got the lift. i have the cst 8" with the stock leaf's..
i cant get the deaver packs, as i tow with my truck and cant afford airbags to go with it. i dont know if deaver makes a leaf pack now that can handle weight? maybe ill have to get prg's traction bars.

shawnwat4 · 08-15-2006, 07:26 AM

mine has no lift on it, and it will do the same when i downshift from 3rd to 2nd. i'm kinda relieved to see its not just me

StuntDriver06 · 08-15-2006, 05:02 PM

Quote:

Originally Posted by beached_titan

possible, but when it literally feels like the transmission just dropped out the bottom of the truck i kind of get the feeling its more than clutches trying to engage

it never did it until i got the lift. i have the cst 8" with the stock leaf's..
i cant get the deaver packs, as i tow with my truck and cant afford airbags to go with it. i dont know if deaver makes a leaf pack now that can handle weight? maybe ill have to get prg's traction bars.

cluthces are the only part of the tranny taht engage/disengage... the bigger tires and whatnot is probably putting a bigger strain on the tranny... dunno just my opinion....

Yellomantis · 08-15-2006, 05:11 PM

Quote:

Originally Posted by beached_titan

possible, but when it literally feels like the transmission just dropped out the bottom of the truck i kind of get the feeling its more than clutches trying to engage

it never did it until i got the lift. i have the cst 8" with the stock leaf's..
i cant get the deaver packs, as i tow with my truck and cant afford airbags to go with it. i dont know if deaver makes a leaf pack now that can handle weight? maybe ill have to get prg's traction bars.

Doesnt the CST kit come with rear blocks? If so, It might be bad axle wrap.