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s10 unlocking axle

THIS FORUM IS FOR ANY QUESTIONS ON THE 7.25" IFS FRONT DIFF, CV HALF SHAFTS AND FRONT DRIVE SHAFT.

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Bret Schmerker
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Re: s10 unlocking axle

Post by Bret Schmerker » Tue Jun 16, 2020 6:43 pm

I concur on the bad motor mounts. Not sure whether Energy Suspension still supports the General Motors M-body (Chevrolet Astro, GMC Safari) with polyurethane motor mounts, but urethane holds up to greater loads than rubber. But 3.42:1 looks awfully tall to me, unless ye're in a state (USA) with higher trailering speed limits than my native California (55max MPH for three-plus axles); my 1997 issue M11006 shipped with a 3.70:1 rearend, but I'm planning for a 9" Currie full-float retrofit with 4.11:1 and an EATON® Truetrac® to accompany a TREMEC® TR-3160B and 10.5" clutch with probably mechanical release (the physical size of the Hydro-Boost contraindicates a hydraulic release) -- the V6-4300 hits peak torque at 2800 RPM.
1997 GMC M11006 (Safari SLE, 2WD, V6-4300/4L60-E/7.625" 3.73:1 open)
Acquired Jul 2018 / In service Sep 2018 - present

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Snowgeek
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Re: s10 unlocking axle

Post by Snowgeek » Wed Jul 15, 2020 4:47 am

Ok here is an update and some info for future disconnect installers. I decided to start by replacing my motor mounts to gain clearance for the disconnect axle tube to be installed. In the end the motor mounts lifted the motor a very small amount..... not enough to install this part.

While I had the motor mounts disconnected I went ahead and installed the diff disconnect with the motor up and out of the way.

Disconnect is in, I chose to use a posi-loc cable actuator for mine which is going to work great..... once I decide where to mount the dang thing.

And when pulling that bone yard disconnect..... don’t forget that big flat washer in the differential. It is the very Last piece to remove. I had to go pull another blazer apart just to get that washer ](*,)

Ryan
2004 Astro (was AWD now 4X4) 125,000 miles: purchased April 2012
Colorado Camper Van poptop
4" Overland lift, Rancho 5000 Cooper AT3 245/75/16 C,
4x4 - NP236 Transfercase
Propex HS2211 propane heater
I am copying a few of you hope you don't mind!

See my build here

Captn. Crunch
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Re: s10 unlocking axle

Post by Captn. Crunch » Wed Jul 15, 2020 1:42 pm

Nice job getting the two piece axle installed. I have one on the floor in my shop I’ve been tripping over for a couple of years now. It came on the cast iron diff I put in the van I pulled it in favor of our solid shaft. I was worried about how the torsen would react to having torque going in and only having one side to distribute it to. Spider gears don’t care about such things but the torsen and it’s design worry me a little bit in that situation. I don’t want to wear it unevenly
Captn. Crunch
"I don't beat my rig-I use it to it's maximum potential"
1994 Safari conversion (sold) and miss'n it!
1999 Safari SLE AWD junked
2003 GMC Safari AWD SLT
cast iron Torsen equipped front diff
S-10 leafs-G80 rear w/3.73’s
2” body lift w/Falken Wildpeak AT’s

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Re: s10 unlocking axle

Post by timelessbeing » Wed Jul 15, 2020 6:15 pm

If you think about it, it would be like having one wheel in the air all the time. I'm thinking that the worm gears inside the Torsen would be spinning like crazy, causing more stress and rapid wear. At highway speed, the disconnected output be spinning unnaturally fast (input RPM x bias ratio), and you would always have reduced power to the front wheels. Bearings would get extremely hot and wear out faster. I think Torsens are designed to work with both wheels engaged at higher speeds.

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Re: s10 unlocking axle

Post by Captn. Crunch » Wed Jul 15, 2020 10:45 pm

Here’s a copy of an email I sent to a torsen manufacturer.

Rich,
Thanks for your interest in Torsen. Under the conditions that you are describing, the differential gearing would spin a high differential rate, but under zero torque load. As long as it is well lubricated, it should be fine. However, I am not aware of ever being paired with this axle configuration in a production application, or if it has been tested. My concern is that the axle disconnected and the transfer case disengaged, the axle's ring gear will not be spinning. Axles typically rely on splash lubrication to distribute oil, and the ring gear is essentially a paddle wheel that flings oil all around. Without it moving, there would be little to actually move the oil into the diff gearing. If this is done, I would recommend making sure that the oil fill level is up close to differential centerline (some axle have the fill level low enough it does not touch the differential), so that you can be assured that oil will flow into the differential without the ring gear moving it. If oil can get into the differential assembly, then the diff gearing will move it around internally.

With all of that said, however, it something of a moot point. We have not produced a differential for the 7.25" axle used by the front of the S-10, so you couldn't run a Torsen in your truck anyway.

Regards,

Rick

JTEKT Torsen North America, Inc.
Rochester, NY
www.torsen.com
585-464-5028



-----Original Message-----
From: Richard
Sent: Tuesday, December 05, 2017 5:52 PM
To: Torsen
Subject: Can I harm a Torsen unit?

Hello
I have a hypothetical question regarding using a Torsen unit with a disengaged axle.
Gm’s S-10 4x4 system has an open front diff with an axle front disconnect. Is there any reason why I couldn’t run a torsen in place of the open carrier whilst maintaining the stock 4wd setup that has the front axle disconnected until 4x4 is selected and the axle is engaged.
Will there be any sort of overspeed or I ever wear concern with only one side of the carrier being driven?
ThanksU
Captn. Crunch
"I don't beat my rig-I use it to it's maximum potential"
1994 Safari conversion (sold) and miss'n it!
1999 Safari SLE AWD junked
2003 GMC Safari AWD SLT
cast iron Torsen equipped front diff
S-10 leafs-G80 rear w/3.73’s
2” body lift w/Falken Wildpeak AT’s

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timelessbeing
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Re: s10 unlocking axle

Post by timelessbeing » Thu Jul 16, 2020 4:05 am

Well there ya go haha. Problem solved.

As an aside, I read that overfilling diffs is a bad idea. It causes aeration of the fluid which ironically leads to fluid starvation in the moving parts. That's probably why manuals specify capacities quite precisely.

Oh and I forgot all about AWD transfer cases. I think the electronic ones wouldn't notice, because they don't care about front axle slip. However the viscous clutched BW's do bias to the rear when the front slips too much. Seems like it would be trying to engage all the time. The S-10s had part-time 4WD TCs did they not?

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Re: s10 unlocking axle

Post by Captn. Crunch » Thu Jul 16, 2020 1:44 pm

Ya the S10’s over its run had the 231 the 223,and the 236. My wonder stems from owning a Zr2 Blazer with the 236. You could shift on the fly from 2hi to 4hi. That would entail the vacuum activation of the collar in the two piece pass. side axle. There was never any grinding noise so obviously all those bits were spinning merrily along at near matching speeds.
Holy cow! Sorry Ryan I’ve totally jacked the thread. I’m gonna open a new post and timeless can transfer this portion of the conversation?
Captn. Crunch
"I don't beat my rig-I use it to it's maximum potential"
1994 Safari conversion (sold) and miss'n it!
1999 Safari SLE AWD junked
2003 GMC Safari AWD SLT
cast iron Torsen equipped front diff
S-10 leafs-G80 rear w/3.73’s
2” body lift w/Falken Wildpeak AT’s

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