DOHC crankwalk?

[Cidacious]

Took my 91 GTP to meineke today because exhaust seems to be louder than my 92 DOHC. They said exhaust fine, flywheel is making noise, hitting engine block, they wanted to pull trans and inspect/replace flywheel. This is with external diagnostics mind you... Went to AAMCO immediately after, they took prybar to the car and said I need a new engine, reman, or used. It shifts smooth and runs fine, there is just a rattle sound coming from trans when clutch is dissengaged and in neutral and sounds like a shaking chain goes away when in gear or clutch pedal on floor. The service manual says the noise is just clutch related... Also my oil pressure is superb w/new sending unit even, 40PSI hot idle. If I had a moving crank I would guess that would be much lower? Is there a way to find out if the engine is toast without pulling the trans? Since shifting is smooth and clutch doesn't slip and dissengages properly what would be the harm in ignoring what AAMCO said and keep driving the car as is? Thanks again guys!!

[pocket-rocket]

Crank walk is from bad thrust bearings. Most likely it (being in a manual transmission car) is from someone holding the clutch in at stop lights when they don't need to, or from someone riding the clutch all the time, putting pressure on the crank by way of the clutch. I'm not accusing you of it, it could have been the previous owner. If the other bearings were shot, yes, you would have low oil pressure. If you wanted to cheapen out, you could just get new main bearings and install them since they come with thrust bearings. This is one of the reasons I don't let other people drive my stuff without me in the vehicle. If you aren't about to take off, put it in neutral and get your foot off the clutch.

[robertisaar]

Bingo...

father in law's ranger has the same issue... he rides the clutch unnecessarily all the time. i know it's his and all, but damn, its annoying to drive like that.

[pocket-rocket]

Speaking of Ranger, with myself, Ben, some Ralley's, a 3400 in the back and some various other things back there, my truck took ~15 seconds to go from 50-70 (or 75, forgot which) in 5th. I remember you talking about how long your father in laws takes to get going. Now I am wondering about the crank in my little truck...

[robertisaar]

damn.... he must have the economy gears or something, because 50-70 in 5th seems like eternity...

you managed it with a real motor in the bed, 2 people and some awesome fast food in ~15 seconds...

maybe my ass-dyno is biased or something.

[walterdude]

What do you guys think of a pilot shaft bearing??? I had one go on my 68 Firebird and the symptoms were the same... Neutral,, stopped and the clutch all the way out it made noise.. Any other time it sounded fine...
I know things have changed in the almost 40 years since I owned that car but, taht should be the same....
Just a thought....
Tom...

[Cidacious]

Is there a way for me to verify Crank end play with trans on car? I saw in specs section what the acceptable range is. If my thrust bearing is shot, is it possible to replace thrust, mains, and maybe rod bearings if come in kit while engine is still in car?

[pocket-rocket]

I pilot bearing is the one in the rear of the crank for the input shaft on the transmission. If that were bad, it would make noise any time the transmission and engine were going different speeds (clutch in) I would assume. The DOHC/284 doesn't have a pilot bearing though. I don't even recall it having a pilot bushing. You could replace them with the engine in the car, but it's going to be a huge pain. Mainly because you have to remove the transmission (and undoing those pull style throw out bearings has always been a pain in my buttocks), crank pulley, timing belt stuff (including the lower timing belt pulley), and remove the timing chain cover to remove the timing chain since it is hooked to the crank. Yes, you read right, I said timing chain. With all of that work, you would probably save yourself a few headaches by pulling the engine, separating the engine and trans on the floor, tossing the engine on a (heavy duty) stand and go to it. Measure first before buying bearings. Better yet, take the crank out and have it checked by a reputable shop before buying bearings, just in case. Don't forget to plastigage everything, disassemble, apply assembly lube and reassemble and retorque everything.

[robertisaar]

X2 on the pilot bearing/bushing. i've never seen a 660 with one IIRC.

[pocket-rocket]

I hope there isn't one. I never put one in the 91 when I swapped in the 5 speed...

I imagine I would have realized this the first time the clutch went in since the trans was an original and not rebuilt.

[Cidacious]

Took car to engine rebuild shop AutoWise for second opinion. They said engine is great, problem is with clutch/exhaust, and they don't do "little" jobs like "just" clutches. Went to another trans shop, said clutch fine, trans needs rebuilt.... Need to find reputable not too expensive trans and exhaust shop.

[robertisaar]

sounds like you need to do it yourself because everyone running shops around you can't agree on a diagnosis...

[Cidacious]

Yeah, I wish I could I have never pulled a trans before, so no lifts or cranes or holders. Also I have a two car garage, and my 92 gtp and 88 Fiero are kept in there. On occation if its cold or hot out I will move the GTP out and use a bay to work, but I guess I didn't plan too well when I built my house. I would consider a trans thing to be long termish (a few weeks) I once helped the GM mechanic at the dealership break open our recently sold 06 HHR man trans and pull the shafts out, that was quite fun, but I don't have the special bearing/case puller thing that they have either.

[pocket-rocket]

If you have a 284 rebuilt, it's going to hurt. They have to be sent back to Getrag in Detroit (if they still do them). Labor is 3k to rebuild them. GM made Getrag sign some funky agreement where they wouldn't sell parts to anyone for them. I'm not sure if this is still in effect anymore though.

[robertisaar]

^ someone on w-body was talking with a getrag rep no more than 1 month ago, and he still couldn't get anything...