NP241 mods? -

southernspeed · March 10th, 2007, 02:29 PM

Hi Darryl, thanks for throwing yourself into the fray with this forum!
I've got a 241 in my '91 K5(well...V10/1500 to be precise!) I'm really pleased with it, the way it performs etc but have 2 questions.
In low ratio it has, and always has had a very audible high pitched whine. Is this normal?
Secondly, just curious as to whether there were any 'hop up' parts for it? Lower ratios? twin stick? (although I can't see how this would be possible).
Any adviseable upgrades?
OK, that was 3 questions but that's inflation for you!
Thanks, mark.

**mikey_d05** · March 10th, 2007, 03:02 PM

The whine is normal. It's the planetaries doing their job. It drives me up the wall but there's not a whole lot you can do about it.

The only "hop up" parts available for a 241 is the SYE. There are some parts available for the 231 but not a ton for those cases either.

Not a whole lot you can do with a 241 other than clock it and take the slip yoke out of it.

MaXXis85 · March 10th, 2007, 04:20 PM

when in lo range on my 243 (electrionc t case non auto trac) it whines in 1st and reverse

darryl · March 10th, 2007, 07:45 PM

mikeydo5 is right there is only the sye kits

these t/cases are noisy in low but have good reduction

actually now that i think about it you could machine the input to take the wider brg used in

the dodge diesel 241dhd and if you have a planet failure use the

6 pinion planets from a 241dld behind cummins in the non dually trucks

the 3 pinions were in the 231 and 4 pinions in most

everything else

is that all clear as mud

or should i try again

**cbbr** · March 11th, 2007, 07:06 AM

I know very little about my 241, so bear with me and educate me please.

It can't be twin sticked? Why not?

What is the advantage of an SYE kit?

**mikey_d05** · March 11th, 2007, 09:27 AM

Correct, it can't be twin sticked. Without going into great detail, the way the case is shifted simply won't allow it. I haven't looked at the inside of one enough to know if the case could even do it provided you could work out the shifting.

The only real advantage to the SYE is driveshaft length, which will lessen the angles your u-joints are subjected to. Another potential advantage is that if you break a driveshaft, you won't end up laying under your rig for a half hour with a 20 oz. bottle and a roll of duct tape.

darryl · March 11th, 2007, 09:54 AM

longer d/shafts mean less working angle for the u-joints

short d/shafts mean more working angles and a better chance of "knuckling "or binding

241's can be twinsticked but it takes machining of the rear hsg for a bushing and seal and the

front case for a seal

**cbbr** · March 11th, 2007, 11:30 AM

Is there anyone that makes or machines the housing? As for the sye, I have a Burb so I really don't think that I need the length.

Cajun4x4 · March 11th, 2007, 11:39 AM

yea with my ext cab truck i could realy care less about the driveshaft length, to me the attractive feature is if i blow the rear shaft i can still drive it, and the oppertunity to have a driveline brake

darryl · March 11th, 2007, 04:06 PM

the machining is more of the custom variety it is done as necessary

most people think that a 241 is not really strong and as you know go to 205 or a atlas or a

203/doublersomething

you are exactly right the 241 in a burb would never have a short d/line issue

there is a lockcollar made to replace the snapring on the output shaft which is really cheap to

buy and works great the ring is sold by axiom up here and is very easy to get

southernspeed · March 11th, 2007, 04:18 PM

I thought as much but thought I'd ask anyway. Thanks for all the input. Darryl, do you have a link for that collar? I've read about it before but can't remember where.

darryl · March 11th, 2007, 04:50 PM

sorry no link i just buy them from AXIOM a trans parts supplier