Bad Torque Tube?

[Icey1174]

I have read posts on here of people rebuilding their torque tube or replacing their bearings. How do you know when the torque tube or the bearings are bad?

[Techno Duck]

Rev the car freely with the clutch let out in neutral. You may or may not hear a rattling sound within a certain RPM range. Usually between 2-3k rpm. The sound goes away if you push the clutch in and do the same.

Same goes with coasting with the car in gear around the same RPM range. Typically it will happen worse in 1st and 2nd gear (much louder).

[jgporsche]

Noticed an odd noise when in neutral, clutch pedal out. It almost sounds like a number 4 rod bearing death rattle. At low idle. Goes away at 1k or more or when the clutch is pushed in. I’m assuming the TT or the transmission (5th gear noise). It’s an 88 944 with only 90K miles. Pulling clutch and TT / transmission this weekend.

(This concerns 968’s only since there are two couplers one on each end, but may pertain to 944's) I replaced the bearings in my TT on my 968 which was a real job, only found one bearing slightly corroded and the other 4 in great shape, turned out to be a 6 month old clutch disk disengaging. When changing these bearings one needs to measure exactly the ends of the shaft in relationship to the tube. You will know why when you go to put the couplers on the transmission end clutch end, something the directions didn’t mention.

[Kiwi944s2]

I have a rattle in this rev range. It is only evident when decelerating or when going down hill. My mechanic has spun the torque by hand (while the trans was out) and there is no apparent bearing noise. Have heard that it is sometimes caused by the 5th gear synchro. I had my transmission rebuilt and a new clutch installed noise was not there before this work was done only appeared after new clutch and rebuilt transmission installed (PS. my car is a 1991 S2)

[jgporsche]

Pulled motor and found rubber centered clutch totally shot. Was using ears in center to move the car. Symptoms were major rattle at idle that goes away when pushing in clutch pedal. Rattle would go away over 1200 rpm. Clutch operated as normal as should. TT seemed fine when turning by hand.

[samgarcia]

Originally Posted by Techno Duck

Rev the car freely with the clutch let out in neutral. You may or may not hear a rattling sound within a certain RPM range. Usually between 2-3k rpm. The sound goes away if you push the clutch in and do the same.

Same goes with coasting with the car in gear around the same RPM range. Typically it will happen worse in 1st and 2nd gear (much louder).

I know this is a super old thread but cam someone listen to the sound my car is making and tell me if it's the torque tube?


https://youtu.be/9Ftercid16c?si=ps_3lz15GSM1nrBi

[SiegfriedS]

The front bearing, just ahead of the shift lever go bad first, due to the heat from the engine!

[Monkey Wrench]

I'm a millwright so I have changed lots of bearings but Have never had my 944 apart.

so there is a tube with a couple of bearings that are internal, cant' bee seen assembled and a driveshaft between, we are trying to figure out whether that bearing is worn.

also there is a problem with the old clutches , with a rubber part that is degrading. Its not just the automatics , but manual models as well right?

I was under my car feeling the CV joints and have been considering just puling it all apart for service and to clean and coat the fuel tank. I think I'll hold off until I can do all the belts ,hoses, stuck brake callipers etc and actually try driving the car.

I found a bit of play that i could feel in the CV joints I dont expect grease will help , if it were a U joint with detectable play that I could feel like that I'd consider that U joint to be "done" so Im thinking my CV joints are "done" I did see there is a procedure to disassemble clean and re-grease but if I know they are bad this wont fix the problem of the freeplay and I suspect it will 'clunk"

I remember in a past post someone had the part number for a compatible VW van part and maybe that's cheaper, or there are aftermarket , probably Chinese parts. or the Porsche dealer parts. I might be best to not worry about re greasing and changing boots but instead just replace the axle shafts with both CV joints and new boots?

Im wondering if I will end up paying around a thousand for a new clutch, I did see some friction material and was curious if I can rivet new material on, then turn it true,
but I suppose that's not going to fix any rubber issue. can I get rid of this rubber part? why is it needed?

my car is in a tent for now, its not heated so I may wait to spring to do a lot more, I figured maybe I can remove the calipers and rebuild them in the warm cozy house to get a jump on things, Ill plan to do all the belts and some of the hoses, fuel system etc in the spring. Lying under it in the cold doesn't sound much like fun.

sounds like maybe I just need to measure the depth of the TT bearing from the end of the tube and replace them, so it's the same distance? If I can extract the bearings I can find the bearing number and obtain new bearings. I don't care if they are OEM just won't put Chinese ones in , I'd want a recognizabe brand of bearing manufacturer that isn't just selling Chinese junk bearings. most bearings are standardized and identifiable by their bearing number, Porsche doesn't make bearings anyway. If Porsche sells bearings, I think they are just acting as a re-seller anyway.

you can find bad bearings by noise, so we are doing that above, you can also sometimes see rust near to bad bearings because all the very fine particulate created by a worn bearing can hang around and look rusty in the area, but you won't see that if its inside a tube. we cant; feel for freepay easily as they are inside and captive.

another way might be if we can detect heat near the bearing, I'm not sure how to take local measurements like that, maybe with driving it then pointing one of those heat sensing detectors? I dont own one myself, anyone do that?

a bad bearing may generate some heat, maybe that's a way to tell ?

I've seen some neat videos where people stick a camera under their car and drive around, looking at how the suspension is reacting and such, I'm not sure that would tell us a lot. interesting to see them though. Heat sensing cameras might help but I dont own one, I think they are very expensive too.

I've been meaning to check the clutch wear as per the manual but if my early 85 is going to have this failed rubber problem maybe its not just the clutch wear I should concern myself with. i doubt mine suffered from aged rubber any better than any other 85. its at maybe 120K , I think. who knows, it wrapped. I dont think it has heavy wear though.

I assume that when I pull the starter to lock the ring gear to change the timing belt that this may give me some view of decomposing rubber particles.

the previous owner indicated that second gear felt a but rough, I dont know at this point if I have bad synchromesh from someone driving it that cant' change gears smoothly , perhaps.

at this point i just want to learn what i can so when i do get in there I'm not all lost with what to do. any obvious parts I should probably obtain before disassembly but i have other cars, and some advantage of not having any definite time schedule.

If I can save a bit of hard earned cash by using alternate parts sources I'm fine with that. My budget is not huge. It might be best to avoid some of the Chinese garbage especially if the parts are hard to get to. The axle shafts , for example don't seem all that hard to re and re. I don't think Id cheap out of the TT bearings, more work to change those.

I figured Id be further along by now but last summer I got a bit distracted with other more pressing car repairs. I fixed some accident damage and repainted my pushed in back bumper, at least I go that sorted out. did some polishing, figured if it looks nice Ill be more inspired to go lay under it. found a pull over tarp at Walley World, it wasn't; expensive , its helping keep it clean in its car tent. Maybe it can sleep better like that ;-)

I have about a thousand in miscellaneous parts ready to go on. I paid 2 K , probably cost 500 for all the stuff to fix and repaint my back bumper. I suspect it'll be 1000 for tires, hoping I dont get stuck needing tires I cant' obtain. It has nice fuchs mags, not the S2 ones. 14 " I guess. I think they are all the same width. I dont think I need the big brake conversion,

it has the back bumper trim like an S2, sports seats. no rust, seems like a decent project car so far. guards red, I like the color.

[djnolan]

The CV's can be flipped side to side and this changes the direction of rotation and the wear surface. Regrease them.

The calipers can be rebuilt, and the brake hoses replaced. Use a small triangular file to dress up the caliper grooves and the caliper bracket and then apply synthetic grease before reassembly.

The suspension can be spruced up with struts, shocks and stabilizer bushings.

When you do front of engine seals and belts, replace all of the fuel, vacuum, power steering and coolant hoses. There are sets of coolant, and vacuum lines you can buy, you have to piecemeal the PS and fuel lines.

TT bearings and clutch are he-man stuff requiring a lift...

[Monkey Wrench]

turning the CV joints around will provide new wear surfaces, that makes sense, except any freeplay will still be there, I think the question becomes how much is too much play? I guess if a degree wheel were mounted it could be defined better than " some detectable play" I'm thinking a degree or so might be the limit before you get clunking noises?

what Ive learned form working on old clunkers is that this play is stacked along with any other freeplay inthe drivetrain. More freeplay is akin to having a hammer with a longer swing and that can cause more wear.
in some cars I've seen this "stacked freeplay" causes drivablity problems. Not so much under load but when coasting and acceleration. deceleration , like driving is freeway traffic at a crawl, then it gets uncomfortable. If you can let the clutch out and go, then it's really not such an issue.

i got what I could of the hoses mostly from rock auto where they are reasonable, rad, water bottle heater core hoses etc. figured I'd have a chance to examine the J boot etc. there seemed to be complete kits for S2 models in silicone. I got some various sizes of metric hose that is fuel compatible, maybe ok for vacuum lines etc , it might be a bit thicker than OEM.

the fuel hoses that connect up near the manifold sound not bad but the little bent one between the fuel pump and filter was around 100 bucks just for a short hose. I think I might be able to save a little by using the aluminum fittings with the appropriate line. someone posted a parts list for the S2 and it's similar but a few different fittings will be needed for the normally aspirated models.

ill pull one caliper at a time over winter, the brakes are stuck on so I can free things up and go deeper in the better weather. the seals and flex hoses were cheap.

I dont know if the pistons will be rusty or not, I guess ill see. some cars have cast iron ones that are chromed and rust gets crawling between the chrome and the casting. I machined new stainless ones for my volvo but I think they are available. It took time so if they are 50 bucks or something, not worth making them.

I don\t own a shop or a lift but I have replaced trannys using blocks and stuff, plywood under and over my floor jack. maybe make a saddle for it? sure it takes way more time than any official repair shop needs. I suspect it's all possible with a certain amount of added time and patience.

its common with volvos not to use OEM rubber sway bar bushings but instead to go to the cheaper and a bit stiffer aftermarket polyurathane bushings. is that a good option for a 944?

rear shocks might be rebuildable? Im not sure what brand but they are yellow. I can probably just undo an end and feel if they are toast.
McPherson struts for other cars, I have compressed before, I won't go there without driving it first. I can borrow the spring compressor tool. I know that's not for the faint hearted and also requires alignment after. I remember doing it with bar clamps and lots of wire! not recommended, a tad dangerous. the shops have better tools for that too, but there are simple spring compressors that can work.

[Customdirector]

Originally Posted by Icey1174

I have read posts on here of people rebuilding their torque tube or replacing their bearings. How do you know when the torque tube or the bearings are bad?

Well, there are a few signs that can indicate issues with the torque tube or bearings. If you notice any strange noises, vibrations, or excessive play in the drivetrains, it could be a sign of a problem.