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Play in transaxle drive flanges?

Old 04-12-2016, 02:58 PM
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CrookedRacer
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Question Play in transaxle drive flanges?

The transaxle drive flanges (the parts that the axles bolt to) on my '88 944 NA track toy are loose.

They can both move in and out of the transaxle by about 1/8". How much play is expected? What's normal? When you tighten the center bolts, should the flanges just be solid? Or could there still be play?

Tonight I am going to drop the axles again, and torque the center 6mm socket head bolts to 18 ft-lbs.

I'm HOPING the bolts are loose and just need to be torqued down. I'm HOPING this will fix my TICK TICK TICK TICK sound.

Is it possible for these bolts to be properly torqued, yet still move in and out independently? I guess I just don't know how the innards are set up to be sure.

Thanks!
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Old 04-12-2016, 06:06 PM
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Van
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Yes, because they're a splined fit into the diff spider gears, there should be some in/out play.

Tick tick tick sounds like a bad CV joint. Try putting the right axle on the left side and vice versa - see if that (temporarily) fixes the problem.
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Old 04-12-2016, 06:15 PM
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Thanks, Van!

I just rebuilt all four CV joints:

https://rennlist.com/forums/924-931-...88-944-na.html

They looked pretty good before and after. I found nothing unusual or ugly.

Before and after the rebuild, the sound is exactly the same. I'll try swapping the axles tonight when I torque those flange-center bolts, but I'm looking for other causes at this point.
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Old 04-12-2016, 06:25 PM
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odonnell
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Originally Posted by Van View Post
Yes, because they're a splined fit into the diff spider gears, there should be some in/out play.
Wouldn't the central bolt on each flange secure it axially? They thread into the diff, no? Unless they bottom out into blind holes in the diff, allowing play along the bolt axis.

CR, can you move the 2 flanges at the same time, in opposing directions? like, both slide outward, both slide inward, simultaneously.
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Old 04-12-2016, 06:48 PM
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As I remember it, each flange can move back and forth about 1/16 - 1/8" individually.

With respect to each other, they can move about 1/8"-1/4" (both in vs. both out)

I don't think the location of either flange makes any difference to the range of motion of the other.

I hope that makes sense.
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Old 04-12-2016, 06:54 PM
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StoogeMoe
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I don't think the axle stub shafts are supposed to move in/out. The CV joints are designed to articulate axially, so there is no need. Yeah, check that center Allen bolt.
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Old 04-12-2016, 07:08 PM
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http://forums.pelicanparts.com/porsc...flange-ok.html

Thread on pelican where some folks tend to agree with Van.

I don't understand why there needs to be so much slop though. I can make the exact TICK sound just by moving them side to side. And if my CV joints want to make them slap around, could that be the noise?

What could be going on internally in the transaxle?

Enough speculation. I'm going home. I'm going to torque those bolts, and we'll see if they are good or not, or if they have any effect on axial play.
Then I'm going to swap the axles and take it for a test drive. I'll report back.
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Old 04-12-2016, 09:48 PM
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What transmission mount do you have?
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Old 04-12-2016, 11:42 PM
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Ok, so I checked the center hex head bolts in the flanges and they were good and tight. The play appears to be normal.

I swapped the axles, and took it for a test drive and it is just as loud, no change whatsoever. If it were the CV joints, you would have heard at least something different.

It's more frequent than once per tire revolution. It's more like 6-10 ticks per revolution. It sounds like a gol durn ratchet.

You know what it sounds like? It sounds like someone put a loose metal flapper against the bolt heads of the cv joints, and it makes a tick sound every time it hits the next bolt head as it turns.

<img src="http://doghouseofbelleview.com/images/fortuneWheelSpin1.GIF" />
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Old 04-12-2016, 11:45 PM
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Originally Posted by FHM View Post
What transmission mount do you have?
stock, I guess.
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Old 04-13-2016, 12:07 AM
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Default Play in transaxle drive flanges?

You can try the following:

Jack the car in the air on jack stands.
Turn the wheels by hand and try to reproduce the noise.

Alternatively, start the car and get it in 1st gear and let the wheels spin the air. Go back where the transmission is and try to locate the where the noise originates. There is a chance that you might have a chipped ring or pinion.
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Old 04-13-2016, 12:16 AM
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Could a bolt have backed out of the driveshaft coupler?

Sounds like the tick could be happening at driveshaft (engine) speed...

About the diff flanges having some in/out play - they are bolted fast to the spider gears, and it's these gears that have some play (so they don't bind up when the transmission is hot).
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Old 04-13-2016, 12:27 AM
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Van, the first thing that came to mind was, sounds possible, and sounds like a PITA.

I suppose that's very possible. I am so sick of removing these axles though!

I wonder if the coupler is something I can get at without removing the transaxle?

Anyway, I will test drive it again, to see if it matches engine speed. The thing is that the sound is only made when the engine is loaded, so you sort of have to keep track of it. But it makes sense.

FHM, I wouldn't be able to make the sound by hand. I would need to do the second thing (spinning wheels on stands) and create some drag on the tires to re-create that loading of the engine. That's the kind of thing you definitely want the cameras rolling for!
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Old 04-13-2016, 12:41 AM
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Sounds like it can be an internal issue in the transmission.

This is how mine sounds and I know it needs a rebuild that I will do this summer.

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Old 04-13-2016, 12:23 PM
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Van is correct - a little play along the output flange axis is normal, like a couple millimeters. If you indeed have 1/8" to 1/4", that is not normal.

It sounds like your ticking may be more frequent than to be expected from CV joints. I'd still start with the CVs if they have not been serviced in several years: clean, inspect, and repack, rule them out as a possible source, chalk it up to regular maintenance.

Other sources for the ticking noise could be wheel bearings (although ticking is not a usual symptom, they more commonly whine), transmission bearings, brake backing shield contact with rotor, torque tube bearings, muffler vibrating against heat shield. Happy hunting!

Last edited by KevinGross; 04-13-2016 at 07:00 PM.
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