Syclone Typhoon Transfer Case swapping.

[Bad Ass Black Trucks]

What would you do?

I pulled the bad T-case out of my Typhoon. It was hopping a little when turning tight corners in the parking lot. Not a huge deal but was annoying and I wanted to get it fixed.

I bought a "good" T-case that was supposed to be for a Typhoon. When I got them side by side my buddy realized the output shafts were different. DOH! That's a Syclone T-case!

I also have a planetary out of a used low mile truck that is supposed to be good.

How can I tell that the Transfer case I have from a Syclone is good when it is not in a truck? I know they are supposed to slip at about 40 ft. lbs or so. But I can't think of a good way to hold the input and output.

Should I pull the output shaft out of the Syclone Transfer Case and put it in the Typhoon Case or just get a new chain and put the used planetary in the Typhoon Case???

 

[DaveP]

Re: Syclone Typhoon Transfer Case swapping.

What would you do?......How can I tell that the Transfer case I have from a Syclone is good when it is not in a truck? I know they are supposed to slip at about 40 ft. lbs or so. But I can't think of a good way to hold the input and output.

Here's one way to fixture a T-case for a bench test:

I have a spare yoke in my stuff. You can also substitute the rear drive shaft as the fixture. Put a big bar through the u-joint so it's blocked against the ground.

The "spec" I came up with is: 10 to 15 seconds to turn the front output 90º at 40 ft lbs on the torque wrench. All three criteria must be met. 40 ft lbs by itself means nothing. Be sure to rotate the front output in the direction that "tightens" the nut. Note that the "time" criteria of 10-15 seconds allows for approximately 30% variation in resistance. Resistance can vary depending on temperature, mileage in service, and how fast you count off the seconds. Sure, this isn't an ISO 9001-quality validation. But I've run this test on several T-cases that were performing satisfactorily, and the "spec" has always held up.

What would I do? I don't know. But here's what you need: A T-case that fits in the truck with a v-clutch that passes the above test, and the other parts in the case such as chain, bearings, bushings, and planets are serviceable.

The basic stumbling block in Sy vs Ty is that the lengths are different. You can't just change the yoke. You need a different rear drive shaft length as well. And Sy and Ty rear shafts aren't interchangeable either. The most expedient solution is to use the best parts from both cases and combine them into a case with the rear output style you require.

DaveP

 

[Don W.]

Re: Syclone Typhoon Transfer Case swapping.

If something similar is not already there I vote this for the vault.

 

[DaveP]

Re: Syclone Typhoon Transfer Case swapping.

How can I tell that the Transfer case I have from a Syclone is good when it is not in a truck?

It occurred to me that you don't HAVE a Syclone rear drive shaft, so you may not be able to "fixture" the test above as I suggested. Try this:

• Remove the rear tail shaft housing. The output shaft is now exposed.
• Remove the little oil scoop thingy so it doesn't get broken. Wiggle and pull gently. It's a loose snap-fit.
• Use a pipe-wrench on the non-splines portion of the shaft to hold it from turning. You're not going to use this shaft anyway, but you should be able to do this without damaging it.

DaveP

 

[Bad Ass Black Trucks]

Re: Syclone Typhoon Transfer Case swapping.

Dave,
Great advice. I had never heard that info and it is much appreciated. I will do the test here soon and report on the results.

Dave, you are correct that I don't have a Sy driveshaft around. Good intuition. I may see if I have a 27 spline yoke around. I may have one from and s-series pickup somewhere.

I did know that the rear of the Sy and Ty transfer case housings were different lengths. But I didn't know if the rear part of the housing and shaft be switched, can they? Lastly is there any way to tell if the chain has stretched? It's not bad pulling the t-case (once you find the body sheet metal holding it in place and pound it out of the way) but I like to take care of things while I have them torn apart.

 

[DaveP]

Re: Syclone Typhoon Transfer Case swapping.

Dave,
But I didn't know if the rear part of the housing and shaft be switched, can they? Lastly is there any way to tell if the chain has stretched? It's not bad pulling the t-case (once you find the body sheet metal holding it in place and pound it out of the way) but I like to take care of things while I have them torn apart.

You're welcome. I'm glad you found the info useful.
Yes, any 27 spline yoke would work for the test. Or, I thought the pipe wrench on the shaft was an OK idea too.
Yes, the output shafts can be changed. It is retained into the ring gear by a large snap ring. The big cases must be split, and the guts removed, to gain access to this snap ring. Personally, I would try to keep a gear-set that was running together, still together in the new case. Although I have changed out planetaries several times with no ill effects for 50K+ miles or more. The tail shaft housings are also interchangeable. Same bolt pattern.

I have NOT come up with a way to ascertain whether a chain is still serviceable. As a matter of fact, I recently overhauled a case that had a "popping" noise. I was sure it was the V-clutch. The chain had some 'sag' in it when held horizontally, but I felt it was probably OK. It wasn't. The case still made the noise. I'm certain the chain was stretched. I will post my findings and comparisons to a new chain when I get around to repairing this case. But it will be awhile.......

If the T-case was catching on the body seam / sheet metal in the tunnel, you had the trans jacked up too high. The trickier task is to get the trans at the correct attitude for re-installation. You have to eye-ball it. Too low and the tail shaft hits the torsion bar cross member. Too high and the case hits the body. I find it easiest if the trans is as low as possible.

Good Luck. Keep us posted on progress.
DaveP

 

[Bad Ass Black Trucks]

Re: Syclone Typhoon Transfer Case swapping.

Well I did the test on the bad Ty case out of curiosity. Wouldn't hardly turn at all with 40 lbs on the torque wrench. Not even with lots more torque. Guess that is why it acted like a 4x4 in the parking lot! Is it a locked up planetary?

Couldn't find my 27 spline yoke/drive shaft in the amount of time I had, hope to locate it soon and test the the other t-case.

 

[Don W.]

Re: Syclone Typhoon Transfer Case swapping.

Hadn't seen it mentioned. Don't forget there is a gasket between the t-case and trans.

 

[DaveP]

Re: Syclone Typhoon Transfer Case swapping.

Well I did the test on the bad Ty case out of curiosity. Wouldn't hardly turn at all with 40 lbs on the torque wrench. Not even with lots more torque. Guess that is why it acted like a 4x4 in the parking lot! Is it a locked up planetary?

This makes me smile. Someone read, understood, and came up with an answer to their problem.

It looks like you have a classic case of a (almost) locked-up viscous clutch. This is certainly the cause of the parking lot jumpiness. It can also lead to parts breakage. I once saw an AWD Astro van that had ripped out the entire sub-frame and busted the ears on the front diff. They scrapped the van, instead of fixing it there was so much damage.

Be cautious of reusing the chain from this case. It's been "worked" pretty good by the binding, and may be stretched. Hopefully the Sy case checks out OK.

If you need BW 4472 parts, Cobra Transmissions is a great resource. I have used them, and was very pleased with the service. Hat-tip: Harmon

DaveP

 

[neildemo]

Re: Syclone Typhoon Transfer Case swapping.

Where would SYTY.NET be without people like Dave P. To Help? Thank You Dave for all your contributions you are a huge asset to this forum. Your knowledge never ceases to amaze me. Just wanted to let you know. Thanks again.

 

[Quickstop [UK]]

Re: Syclone Typhoon Transfer Case swapping.

Why are the t cases different? So many other parts are compatible, you'd think obvious items like this would be.

Good info. If you're going to vault this, where is the info for testing it still in the truck?

Thanks Dave.

 

[blacktyaffair]

Re: Syclone Typhoon Transfer Case swapping.

Where would SYTY.NET be without people like Dave P. To Help? Thank You Dave for all your contributions you are a huge asset to this forum. Your knowledge never ceases to amaze me. Just wanted to let you know. Thanks again.

:stupid: Awesome info! This is the next project on my list and this thread has helped me lots before I even get dirty. Thanks DaveP.

 

[cloneman315]

Re: Syclone Typhoon Transfer Case swapping.

I posted this up a while back if it helps yah any

http://www.syty.net/forums/showthread.php?t=70643&highlight=transfer+case+comparison

 

[Bad Ass Black Trucks]

Re: Syclone Typhoon Transfer Case swapping.

I posted this up a while back if it helps yah any

http://www.syty.net/forums/showthread.php?t=70643&highlight=transfer+case+comparison

Thanks, useful pictures!

 

[Bad Ass Black Trucks]

Re: Syclone Typhoon Transfer Case swapping.

This makes me smile. Someone read, understood, and came up with an answer to their problem.

It looks like you have a classic case of a (almost) locked-up viscous clutch. This is certainly the cause of the parking lot jumpiness. It can also lead to parts breakage. I once saw an AWD Astro van that had ripped out the entire sub-frame and busted the ears on the front diff. They scrapped the van, instead of fixing it there was so much damage.

Be cautious of reusing the chain from this case. It's been "worked" pretty good by the binding, and may be stretched. Hopefully the Sy case checks out OK.

If you need BW 4472 parts, Cobra Transmissions is a great resource. I have used them, and was very pleased with the service. Hat-tip: Harmon

DaveP

Dave,
Thanks for the compliment. I'd like to think I am no slouch. Made it out of college with a couple of degrees :roll:
I did want to give an update even though it has been a while. I picked up a used Ty T-case when I bought some other other parts in a package. The transfer case passed the 'Dave P' test in about 12-13 Seconds. The seals are in good shape but I'm going to open it up and clean it out and try to do a visual on the chain. Might replace the chain just to be safe.

 

[Mobile22]

Been through the ringer on this transfer case swapping. One I found this in different forum I figured it all out. I acquired a rebuilt SY transfer case with exact part number on the blue/green tag bolted to the front housing. However, I discovered the hard way that the output shaft had been converted to the larger 32 spline shaft and longer TY tail housing. All you need to really no look at is the part number on the tail housing which is readily visible. 44-72-066-901 is SY and short with 27 spline shaft or 44-72-066-901B is TY which is much longer with 32 spline. My understanding is all you need to do is change the slip yoke and you should be able to retain the SY driveshaft

BW1372/BW4472 Information - International SyTySGT Forums

The following information I've gathered over the years from transfer cases I've either had, worked on, or just seen in my travels. It basically answers the question

sytyregistry.com