1320Fastback

Lack of oil?

manvstaco

Yes, I have a 93 suburban with a 91 cummins(year on the tag) a 47rh transmission, and a np241DLD t-case. Dana 44 front axle with manual locking hubs, 14 bolt rear axle
The t-case was plenty full of fluid, I left a trail about 300 yards long of fluid. I was reading that the front driveline causes these t-cases to split so I'm hoping this is where all my crazy vibrations were coming from attempting to go faster than 60. It's just weird cause it was like it would defuel or fight back through the pas pedal which was odd for a driveline issue.

twostep

Where the hubs unlocked? If so the front DS shouldn't have had any load on it... basically not spinning.

1320Fastback

300 yards is a good trail, beats my record that's for sure.

Yes with manual hubs the driveshaft shouldn't of had and force going thru it and if it was spinning would only be from parasitic drag.

The 241 is a very good TC, second only to the 205 in my book.
It is chain driven but the chain only spins when in 4x4 so they last a very long time.

The output bearing can take a beating if your running a lift and the rear driveshaft spline is pulled out a ways or of course rotten ujoints.


Defiantly a interesting problem. Not being able to get above 60 sounds like friction holding
you back like a Tcase bearing until it couldn't take it anymore and grenaded.

Heind sight of course.

manvstaco

Hubs should've been unlocked unless a little kid was playing with them in the driveway
I really doubt someone locked em on me. I have only had this truck a little over a month and never played with 4x4 yet. the t-case lever was all the way forward so that should be 2wh. I really hope swapping this t-case and removing the front DL solves this 60+mph problem as I'm stumped.. I'l drive down to the tranny shop later today and take a peak at the hubs for you guys

Angry Johnny

But yet you say you could exceed 60 MPH with the O/D off right? I think there is more at play here. If you have it at a shop have them pull the trans pan and look inside.

manvstaco

I got it up to 63mph with the TC locked up and not in OD the other day when I made that diag video. was flooring it as hard as I could to get going that fast

BHD

What gear set do you have? I am going to guess 4.11s with the Corp rear. I think with 37 inch tires you should be able to hit 65 just before defueling in Drive.

I watched your video a few times and at that 10:20 to 10:30ish point it looks like you are experiencing a bad vibration based on the return spring and the throttle cable.

In my opinion, which isn't worth much at times, I would expect to see the same behavior in each gear at the same RPMs if your problem was fuel and engine related. Because your symptoms seem become noticeable only in OD, I would start with the transmission.

Anyone else agree or disagree?

manvstaco

I just text the PO, he said it has 4.11 gearing

Angry Johnny

I agree with BHD, the transfer case breaking like that could be the result of the condition and not the primary cause. You or the shop are already there isn't much more to pull the pan and look. I suspect the thrust bearing in the O/D unit has gone bad and possibly has done other damage in there. That bearing takes quite a load when in O/D.

patdaly

I know you said the front hubs should have been unlocked, but I would PHYSICALLY verify that the ratios of the front and rear axle match. Especially with a swap vehicle that you just bought, you have no assurance the PO didn't do something stupid like match a 3.42 10 bolt rear with a 3.55 Dana 44 front and call it "good enough".

Trust, but verify is my motto.

manvstaco

Agreed, I'll call the shop in a bit and request the examine the pan before proceeding. If I need a rebuild I might just swap things over to a 5 speed manual as I feel it would be cheaper and more reliable in the long run. Thanks for all the help so far guys!

jtamulonis

I just looked at my `94 suburban with the 241 transfer case and all the way forward is 4low. all the way back is 4 HI, and one notch forward from there is 2 Hi. I think you were in 4 low and that`s why you could not go faster than 60 mph. one of my grand daughters messed with the t/ case lever and my wife and I both thought the posi in the rear end was locked up because the `burb would bind up pulling into or out of parking spaces. after a few months, the binding went away and we forgot about it until one day we needed 4 wheel drive and it did not work. the electric sol on the front axel disconnect was burned out. that`s when I noticed the T/case lever was in 4 Hi. a few months of running down the freeway at 75 mph did not seem to hurt the T/case, but I feel like a fool for not noticing the shift lever in 4 Hi. I put in a cable shifter in place of the electric sol and all is fine now. there got to be a drive shaft vibration while we were driving all over God`s green acre, it went away when I removed the drive shaft and had a new splne shaft put in the drive shaft and a new slip yolk. check your shift lever shift pattern. it should be the same as my `94.

manvstaco

I believe you have the np241c transfer case which does match your shifter positioning in the dash, mines the np241dld which is meant for dodge vehicles and the positioning is different. When I'm in 2wh on my t-case it says 4L in the cab. I was driving over 75mph when I bought it and never changed the position of the shifter. Anyone else agree on the np241DLD shift pattern being different than the np241c?

I think this is gonna turn into a winter project if the automatic transmission is bad tomorrow when they pull the pan. If I'm spending the money on a rebuild I'm swapping for a 5speed

oliver foster

The Dodge NP-241 DLD of the year that would be consistent with the 47 RH you have in your Chevy would be as follows:

2H
4H
N
4L

So yes you should be all the way forward to be in 2H.

As far as what sort of T-case / shifter pattern Chevys use, I am of no use...