89 944 Turbo Input Shaft Play (driveline slack)
05-18-2016, 10:08 AM
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89 944 Turbo Input Shaft Play (driveline slack)
I have a driveline slack problem when i let off the gas. The axles are tight, when i remove the access plate on transmission with car in gear i have a little bit of rotational play. I am guessing that is not normal and the problem is the pinion in transmission. What else could it be? is shimming the pinion a DIY?
05-18-2016, 10:20 AM
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Did you do that test with the clutch in, or out? There are 3 gear meshes total between the input shaft and the CV axles, so you can expect some gear lash, unless it was excessive.
In every 944 I have driven, there is some amount of "backlash" when you let off the gas suddenly. I wrote it off as the driveline acting like a torsional spring... the clutch center loads up and so does the torque tube shaft when you are transmitting power through it, slightly, which stores potential energy. So when you lift off, it unloads and you can notice it.
In every 944 I have driven, there is some amount of "backlash" when you let off the gas suddenly. I wrote it off as the driveline acting like a torsional spring... the clutch center loads up and so does the torque tube shaft when you are transmitting power through it, slightly, which stores potential energy. So when you lift off, it unloads and you can notice it.
05-18-2016, 11:40 AM
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actually wondering if its a clutch issue. Trans in neutral, the shaft going from engine to trans should not move at all right? i am turning it from inside the inspection plate on trans. The clutch is a centerforce
05-18-2016, 01:24 PM
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In every 944 I have driven, there is some amount of "backlash" when you let off the gas suddenly. I wrote it off as the driveline acting like a torsional spring... the clutch center loads up and so does the torque tube shaft when you are transmitting power through it, slightly, which stores potential energy. So when you lift off, it unloads and you can notice it.
Good call in checking the axles, too- I started getting some weird play and clunking that turned out to be all 6 of the triple-square bolts attaching the driver-rear axle to the hub having nearly backed out! Guessing someone forgot to torque them at some point, and they finally worked their way loose. Thankfully, the CV boot is big enough to keep the bolts from backing out completely, otherwise I'm guessing I'd have been down a few bolts!
05-19-2016, 06:16 AM
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With trans in neutral, but clutch pedal up, the shaft should not move at all because it would be locked by the engine not being on. The lash you are feeling is probably the worn out spring cages in the clutch disc's hub.
If you want to check tranny lash, put it in gear, pull up the e-brake, and have someone hold down the clutch pedal. If you feel any lash, it's either in the gearbox, or axles, and it should be easy to confirm/eliminate the axles by watching them.
If you want to check tranny lash, put it in gear, pull up the e-brake, and have someone hold down the clutch pedal. If you feel any lash, it's either in the gearbox, or axles, and it should be easy to confirm/eliminate the axles by watching them.
05-19-2016, 09:46 AM
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Thanks, looked at it again last night, with clutch pedal not depressed i would say its about 1/16 play twisting it back and forth. Not sure if that would make the car have the driveline slack i am feeling while letting off the gas.
will that amount of slack hurt the trans? Does seem like the clutch springs, clutch is years old but only has about 2k miles on it. Its a centerforce.
thanks
will that amount of slack hurt the trans? Does seem like the clutch springs, clutch is years old but only has about 2k miles on it. Its a centerforce.
thanks
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05-20-2016, 09:23 AM
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Checked with cluch depressed and trans in first gear. The input shaft to the trans rotates about 1/4 turn back and forth. Looks like my slack in driveline is from trans. Is this common problem on 94 trans to happen? Total rebuild or is it something else?
05-20-2016, 12:31 PM
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Watching this thread with great interest. I have 6 951s. I've had 3 transmission rebuilds and 5 new clutches including a rebuilt 968 transmission in 30 years. In Every case I had this driveline lash. If we can find the solution if be very happy!
05-21-2016, 03:40 AM
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Jon951, if you've had 3 trans rebuilds, you're in a good position to tell us what the solution is. What did your rebuilder find out when they opened them up? Which parts needed replacing?
djtalon, that's a lot of lash. You can either have that trans rebuilt, or find a decent used one to put in.
I've only had the two 951s that I have now, and one of them does have some lash in the trans. The other one is tight. Also, my spare 951 trans has no lash. So not much of a data point, but one of my three 951 transmissions has a lash problem.
djtalon, that's a lot of lash. You can either have that trans rebuilt, or find a decent used one to put in.
I've only had the two 951s that I have now, and one of them does have some lash in the trans. The other one is tight. Also, my spare 951 trans has no lash. So not much of a data point, but one of my three 951 transmissions has a lash problem.