Running w/o CV axels

[Paveltolz]

I'm trying to figure out why the truck feels like it has a two ton trailer behind when getting off the line. With the upgraded motor and tune along with a rebuilt transmission and no love for the effort, have decided to see if it has anything to do with the drive line creating rolling resistance as I'm out of ideas.:???:
The Front Differential has given me issues in the past so I want to isolate it by removing the front drive shaft and the CV axels (which are starting to clatter).
I replaced the front hubs/bearing units and I'd like to give it a test run of a few miles without the axles before I plunk down money for a rebuild on the front diff. That and or the Transfer Case. Question is, will I screw anything up or damage the new hubs by doing so?

The tires I'm running are the Falkin Rocky Mounts. Not happy with them anyway and in a rolling test they aren't as good as my old BF Goodrich A/Ts were. But, I had this 'heavy' feeling even with the BF Goodrich's...like I said, I'm out of ideas.

 

[6.2 turbo]

Ive done it,with just gutted outer cv joints. You need them to keep the bearing together.

 

[THEFERMANATOR]

If you run it without the stub shafts inside the bearings, the hub bearings WILL come apart. The stub shaft and the 36MM nut is what holds the bearing together, and is why it requires so much torque. You can take your CV's apart and put just the stubs back in and drive it, but you MUST have something in there stout enough to have enough torque on it to hold the bearings together.

 

[Paveltolz]

Thank you sir for saving me from myself. I had a feeling it would be something like that. I had thought about putting just the stubs back as you suggested.
Regardless, I'll be sure to NOT DRIVE without something in there.
Hope you're doing alright and that your surgery goes better than expected.

 

[3500GMC]

As for the drag feel, maybe a sticking e-brake or caliper.. Are we sure you are actually in 1st gear starting out?

 

[Paveltolz]

As for the drag feel, maybe a sticking e-brake or caliper.. Are we sure you are actually in 1st gear starting out?

I had the brakes checked out to double check me and all four corners are fine. It does feel like an e-brake but I know when its on and when it's not. I don't have any brake smell either at the end of any drive.

Yup, starting in first. I count the gears often (I need professional help) and its 1-2-3-4 with torq lockup in 3rd and 4th (technically, a six speed?).

 

[WarWagon]

The 6.5 just isn't an out of the hole engine. It needs to rev a little before you get power. One of the reasons the small turbo was put on by GM was no doubt to overcome this. It is one reason I am experimenting with a higher stall converter when I get to it.

You have a lot of inertia to get moving in this heavy engine. Big heavy tires with steel rims also take power to get moving.

You can grab the front propshaft and see if it will spin over by hand. It should assuming 2WD high selected.

The other stuff you drive my mess up your feeling of 'quick'. Over stock tune and turbo I am sure you have gone from 'can't get out of it's own way' to 'snappy and pulls hard'

 

[dangerousdave]

I had the front brake hoses start to fail in a weird way; they started to collapse causing the same sort of feel. It got worse as they heated up which was REAL fast. After letting them cool down enough to work on. the pressure would dissipate.
Took me a while to figure it out.
Braided Stainless Steel Brake Lines with Teflon liner cured it and it stops better than ever before. IIRC about $75 for the Burb.
I hope one of the site sponsors sell them.

 

[WarWagon]

A restriction in the return line from the hydrobooster will cause slow release of the brakes. Some people mod their hydrobooster for quicker brake release. Issues with the hydrobooster itself can also cause slow release.

 

[ak diesel driver]

my vote is the camshaft

 

[Will L.]

Has he truck always felt his way? What is you 0-60 time so we know how sluggish you are referring to.

 

[Paveltolz]

Ive done it,with just gutted outer cv joints. You need them to keep the bearing together.

Thank you too sir. I somehow missed your response...very much appreciate your quick answer.

my vote is the camshaft

That's just mean spirited...answer is nope.
I've driven four trucks with the cam upgrades now and mine, being the fourth is the pig. It was with the old motor, it still is now. At 65 it feels lively as hell and even with the GM-5 it pulls hard up to where I quit pushing at 90-95 (Cops, traffic, tires...gotta say "When"). On clear roads with 635 waaayyy out in front I did touch 120 and it was still pulling. So, no, it isn't the cam.

Has he truck always felt his way? What is you 0-60 time so we know how sluggish you are referring to.

Yup. Bill had the truck up there last year (long story) and said it felt like it had the E-Brake on when compared to driving his and that's just rolling off the line in normal driving around town, not going for it. That was with the old motor and he's made the same comment with the new one. For what it's worth, he said the same about his truck before a new motor and cam went in his.

My 0-60 times with the old motor were between 13 and 15 seconds. Dead stop-hammer down or rolling start and staying on the 'power band'. Mostly it was air temps that made the difference.

0-60 with the new motor are around 12 seconds.

I know these things aren't quick out of the hole, regardless of turbo but I can tell you, having driven the others which are heavier and have the same rear 3.73 or 4.10, turning 8.5 in a 2500 0-60 and watching the 3500 leave it behind...it leaves me scratching my head so 'we wonders, yes precious, we wonders.'

Tires and wheels have received the big pointy finger a few times so I've a set of OEM wheels I'm going to fit with some 'low rolling resistance' tires which should at least help get the EGTs under control and eliminate that area of contention. We'll see. Now it's off to help another 6.5er up in Bountiful with some electrical issues.

Back to my troubles later today.

 

[ak diesel driver]

Paul Correct me if I'm wrong but I thought I remembered reading that you didn't use the standard cam of Bill's in your build due to clearance issues???

 

[6.2 turbo]

Are you running a 6.2 ? You might have too much injection timing at low rpms.

 

[Burning oil]

Weird problem, same gears, same HP/tourqe, same weight. Should have same results. It must be driver error? :driving:

 

[GM Guy]

I will jump on the blame the 4wd bandwagon.

hows the t-case? what oil is in the diffs and t-case?

 

[Paveltolz]

Paul Correct me if I'm wrong but I thought I remembered reading that you didn't use the standard cam of Bill's in your build due to clearance issues???

You and me both but, as it turns out, he got it sorted out and instead of the originally planned HP-3 I'm running the HT-4. He realized a marginal performance difference between the two and trimmed inventory to just the one. He did some more calibration measurements and I think he trimmed the valves a calibrated smidge, if at all. I was just teasing with the 'Mean Spirited' comment by the by.:hello:

Are you running a 6.2 ? You might have too much injection timing at low rpms.

6.2 block (660) with 6.5 heads. I don't have the best of scanners but the Palmer software gave enough info that in one of my many chats with Bill he said that was within specs. I've lost the file recorded (hard drive crash) or I'd post it up. The pump is the new Stanadyne ULDS, er, ULSD units. Air Dog is registering 9 psi and doesn't dip below 8 under any acceleration conditions.

Weird problem, same gears, same HP/tourqe, same weight. Should have same results. It must be driver error? :driving:

That's what got us stumped and it leaves driveline and tires to blame because (stupid human comment follows) I refuse to believe it could be little ol' me :rof:
Tires: The other trucks run BFGoodrich Commercial A/Ts, OEM sizes. 635's truck, Tall tires on 19.5" rims x6 Me, 31" tall 285s on 17x9 rims.
Roll down into Ellensburg WA out of Yakima starting at 70mph at the crest and shift into neutral. The other trucks reach upwards of 80-85mph. My truck slows to 61mph with these "Fulkans!" With the same size BF Trail A/Ts it rolled up to 83mph.
On a local hill starting at 55 I can get up to 57 where 635 gets to 64mph. Yeah he's got me by a ton with the 3500 dually so there's that to consider.
I picked up a set of 255 x 45 Eagle M+S tires on 17 x 8 rims and endured the embarrassment of that sight for an hour. That was ugly. SS-Steve said, 'it doesn't look bad.' I thanked him for his kindness and outright lie with 'are you kidding, its FUGLY Looking.' He found honesty after that and we both had a good laugh.
But, no change in the local hill roll test. Still topped out at 57mph.

I will jump on the blame the 4wd bandwagon.
hows the t-case? what oil is in the diffs and t-case?

T-case and both Differentials are original with new oil whatever spec the data sheets call for 5000 miles ago. Transmission was just rebuilt 3000 miles ago. Both transmission and rear diffs have larger covers/pans (MagHytech).

Rear brakes were done with new drums and shoes too long ago to remember but before we moved out here which means five years ago. Checked by Midas 2000 miles ago and were said to be adjusted correctly. Calipers are a year old and the pads are getting to the point of replacement.

Off the ground, front tires spin with the noise of light pad contact. Rears turn as well as I could expect with the driveline and all attached.

So, after helping a brother 6.5er all day yesterday, I'm going back under the front today to replace the left hub, remove C/V axel, disassemble both of the old units and insert the splined portion so the hubs stay together (thanks again for saving me from myself) and remove the front drive shaft.

For what it's worth; regardless of turbos (GM5, 8), tires, tunes or injectors (HO vs Standard)...the EGT's remain the same (and higher than 'norm') at all cruising speeds (GPS tracked) over a couple of miles of flat ground. 400-50mph, 500-60mph, 650-70mph. Acceleration to 70 from zero (riding the power, not standing on it and letting it catch up to the pedal) nets 11-1200. Normally, this would be for another forum but the point is, something is dragging the truck down...

 

[Burning oil]

Front end alignment? Tires wear even? Do rear tires track inline with fronts? Ever been in a wreck maybe front to rear track is off?
Is parking brake on?:hihi:

 

[Paveltolz]

Front end alignment? Tires wear even? Do rear tires track inline with fronts? Ever been in a wreck maybe front to rear track is off?
Is parking brake on?:hihi:

Alignment is good, Tire wear is even and front tracks with rear. Didn't always track right. I had the devil's own to get the thing to quit pulling right. That was in NC. Once out here I had a shop look at it and they pointed out the right front was damaged. The truck was a work truck and I guess the hired 'care nothing for the equipment' hands slammed it against something or dumped it in a hole hard enough to bend the lower control arm bracing back a bit. The shop put it on a rack, chained it down and pulled it into spec. Truck's not had an issue other than following the road crown since.

Parking brake has been checked and cleared as the problem. I brought that up to the Midas guys too...no 'luck.'

One side is done. I couldn't get the CV to separate from the axel...lockring defeating my efforts on that one so I've got the right tool now. 'Should be easy.' The driver's side hub refused to come off. Felt like it was welded to the CV and frozen to the whateveritscalled. That and it won't spin without leverage for love or money so I may have the cultrate. If only.

 

[Burning oil]

Sounds like like your onto something! Maybe video time so we all can enjoy your effort.