Welded Center Differential AWD Trans, binding?

[razrman8]

About 500 miles ago, I replaced my transmission with a rebuilt AWD transmission. All new gears, shimmed, welded center differential, etc. Transmission is good for 600hp.

Now, I have noticed with the welded differential, that sometimes I will get some horrible roaring out of the car. Like, I can feel it all through the car. As if an axle was bent on front and rear. My car is not jumping off of the road, but that kinda gives you an idea. But, I have come to notice, it is typically bad after super tight turns.

My question is, do you think that the welded center differential, which is turning all tires the same, puts the wheels in a bind after sharp turns and does not wiggle itself back and causes the shuttering of my car? This started after my transmission swap. only thing different is the welded center differential. Any other ideas?

I'll be back on after a few hours, going to work for a bit. Figured I would put this out there now and take some input. I will be back on soon for replies. Thanks guys, ahead of time.

 

[talondave]

I had a welded center diff for 2 years and never had a problem... Kinda sounds like your trans and tcase are not a matching pair! Like you have a trans from a 95-96 and your tcase is out of the 97-99... or vise versa!

You could type in your trans Id number on google and it will tell you what year it is, but wont do no good if some one swaped out the guts from another case!

 

[razrman8]

They should be. Because I had to trade my old one, trans and tcase, for my new one. I'm not saying I it couldn't.

 

[talondave]

They should be. Because I had to trade my old one, trans and tcase, for my new one. I'm not saying I it couldn't.

I would make sure you have a matching trans and tcase! Thats the only thing I can think it could be, besides your tires being different sizes!

My car would bind up making turns, but would be perfectly normal going straight... On the street, mine drove like it was a stock trans!

 

[razrman8]

I just talked to the guy I bought it from. And he said he was pretty sure that they were the right match, but that it was possible that it could be wrong. What is the easiest way to verify that they are the right match?

 

[96awd]

I just talked to the guy I bought it from. And he said he was pretty sure that they were the right match, but that it was possible that it could be wrong. What is the easiest way to verify that they are the right match?

Spline count.

Lewis Ludwig via MyTouch 4G

 

[dexterholland04]

You could type in your trans Id number on google and it will tell you what year it is, but wont do no good if some one swaped out the guts from another case!

^This

 

[94_TSi]

The splines will be the same for 95-99. Go to http://www.jackstransmissions.com/pages/tech-articles , then you can test the t case to correctly identify it.

 

[jrohner]

If you can push the car by hand, the tcase and trans are matched up. I had a mismatched tcase & trans with welded center diff, and it was basically undriveable. My rear diff got extremely hot in a few miles.

 

[talondave]

I just talked to the guy I bought it from. And he said he was pretty sure that they were the right match, but that it was possible that it could be wrong. What is the easiest way to verify that they are the right match?

The easiest way, and the most proven way would be to pull the trans and tcase!

<iframe width="420" height="345" src="http://www.youtube.com/embed/GK6d-BFMW84" frameborder="0" allowfullscreen></iframe>

 

[razrman8]

I can push it by hand.

 

[jtmcinder]

It's strange that the problems are after a sharp turn. As you know, a welded center causes grief during a turn, but not after. Maybe you have enough slop in the drivetrain to effectively store the difference, which then gets released once you're going straight. To test this, lift one wheel and, with the car in gear, see how far you can rotate the lifted wheel. That's a half-tushed measure of the slop.

 

[razrman8]

And what exactly would this be telling me.

 

[4pistons]

Do you have an aluminum flywheel??

Rick - '91 GSX (Over 10 years driving on a welded diff!)

 

[razrman8]

Stock flywheel.

 

[razrman8]

And maybe its not just after a sharp turn. I don't know maybe I'm crazy.

 

[jtmcinder]

And what exactly would this be telling me.

If that was to me, then the answer is the last sentence of what I wrote previously: you are getting a measure of the slop (or lash) in your drivetrain. Why do you want this? Because a drivetrain with slop won't bind immediately; first it uses the slop to deal with the difference between the front and rear in a corner. If you have a ton of slop, not only is this bad in general (and contributes to failure on launch), but it also might delay when the binding appears until long after you start turning.

 

[razrman8]

Ok, well while I was out driving yesterday, I kind of noticed I get the shuttering when my suspension compresses. Like going down a wavy road, up and down. Compressing everything, can this affect the drivetrain? If so, what can be going on here? I'm wondering if I may have a bad axle or somehthing. But I feel it thoughout the whole car. Sometimes I feel it right at my seat, as if it were the t-case, then sometimes I question it. Hell, I don't know.

I feel it when putting a load on the engine, like pulling from a stop, and laying into it kinda.

I think it may be time to check wheel bearings. When I am getting the vibration, it goes away when going into a nice crusing turn. Completely stops. Gosh, maybe I have more than 1 problem.

 

[99gst_racer]

Sounds like mismatched components to me too.
Verify the stamped number on the bellhousing.

Per Tim Zimmer:
W5M332NPZT is 1995-1996, W5M332MUZT is 1997-1999.
The only difference in the transmissions is the final drive due to the front diff ring gear having 58-teeth on the early ones and 57-teeth on later ones.

 

[razrman8]

Mismatched transfercase to transmission? Tim is actually the guy who sold me the transmission. He's trying to help figure it out as well. Wouldn't mismatched components be super harsh? Hope I haven't damaged something.

 

[99gst_racer]

Tim knows far more about it than I do. But, you'll need to match the tranny, t-case, and rearend. With as small of a difference as the transmissions are, mismatching wouldn't be super harsh, but would cause binding and unnessacery stress.

 

[razrman8]

Ok, my statement was false. Tim did not sell me the transmission, the OP of that thread: Ian, is the one who sold it to me. I was told by him, that as long as I had the 95 transmission and tcase I would be just fine. Basically, from what I am gathering from this information, is that I need to do a little verification of things underneath the car.

 

[twicks69]

What is Ian's last name or is there a serial number of mine stamped on the transmission case for verification?

As for testing transmission and transfer case gear ratios, Jack has a simple video on his website for testing these issues.

If the Tcase or trans front diff ring gear is not a matching set, you would be doing approximately a 2mph difference between front to rear for wheel speed.

Tim Zimmer via Evo Phone

 

[razrman8]

According to DSMLink forums, it's Ian Drury. I am pretty sure he's the one that sold it to me. That makes sense about the 2mph difference.

 

[twicks69]

I don't show records for that name unless I built it prior to 2009 off business records. You are certain it is one of mine? I almost never use welded differentials in my transmissions due to drivability problems associated with them.

If it is a gear ratio issue, the car should feel loaded down under straight driving and feel like a power loss, then act funky coming out of turns. That would be a ring gear not matching the transfer case ratio issue.

Tim Zimmer via Evo Phone