This is getting old fast !!! - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Bowed · 12-04-2002, 10:18 PM

For the second time I took out the 3 speed standard transmission in the 75 C10 that I got recently , trying to find that mysterious knocking noise that comes from the bell housing area ( It had the noise when I bought the truck ) and while looking thru the repair manuals I noticed the bolt pattern did not match any thing in the manuals . It has a 5 bolt pattern and all the transmissions in my manuals are 4 bolt pattern so now I wonder if my problem is that some body put a mis fit in there . The trans is a GM21 ( 352259 ) ( H30 -4 ) can any body tell me if this is for 75 chevy ?

Stano · 12-04-2002, 10:27 PM

I have had both kinds of trannys in my 67 before. 4 bolt pattern and 5. They are out of the mid 70's and up I believe. As far as the noise you mentioned it might be your throw out bearing. I have had them make tapping noises and such even new ones.

BLAZERMAN · 12-04-2002, 10:31 PM

Are you sure the noise is coming from the bellhousing area and not the rear end, sound will often travel thru a driveshaft?

Bowed · 12-04-2002, 10:44 PM

Running with the drive shaft off still makes noise , running with the trans out there is "NO" noise so the clutch and plate must be OK and not hitting any where . The clutch fork and throw out bearing are brand new from when I took it out a couple of weeks ago . There was some mickey mouse work done on the linkage so Im thinking may be some mix and match done on it to cause a problem .

fast_dev · 12-04-2002, 11:32 PM

i have seen a bad pilot bushing make a knocking noise, sounded bad. Dev.

12-04-2002, 10:18 PM	#1
Bowed Registered User Join Date: Oct 2002 Location: where it's hot Posts: 1,059	This is getting old fast !!! For the second time I took out the 3 speed standard transmission in the 75 C10 that I got recently , trying to find that mysterious knocking noise that comes from the bell housing area ( It had the noise when I bought the truck ) and while looking thru the repair manuals I noticed the bolt pattern did not match any thing in the manuals . It has a 5 bolt pattern and all the transmissions in my manuals are 4 bolt pattern so now I wonder if my problem is that some body put a mis fit in there . The trans is a GM21 ( 352259 ) ( H30 -4 ) can any body tell me if this is for 75 chevy ?

12-04-2002, 10:27 PM	#2
Stano Registered User Join Date: Jul 2000 Location: Mo Posts: 963	I have had both kinds of trannys in my 67 before. 4 bolt pattern and 5. They are out of the mid 70's and up I believe. As far as the noise you mentioned it might be your throw out bearing. I have had them make tapping noises and such even new ones. __________________ New daily driver 96 Chevy K3500 crew cab dually 53,000 miles 350 Vortec 4L80 Nice ride 67 Chevy C-10 LWB Built 350 TH-400 Wifes ride and family rig: 2001 Furd Expedition 5.4 Liter Kickin back in Rolla,Mo. USA "Do the thing you fear most and the death of fear is certain" Mark Twain

12-04-2002, 10:31 PM	#3
BLAZERMAN Currently Blazerless Join Date: Apr 2000 Location: St. Joseph Mo. Posts: 4,826	Are you sure the noise is coming from the bellhousing area and not the rear end, sound will often travel thru a driveshaft? __________________ 1972 C/30 133" W.B. C&C 1970 GMC 3500 157" W.B. single wheel C&C

12-04-2002, 11:32 PM	#5
fast_dev Registered User Join Date: Dec 2000 Location: Ringtown,PA Posts: 555	i have seen a bad pilot bushing make a knocking noise, sounded bad. Dev. __________________ 68 chevy 406 small block, budget drag racer, new best e.t 11.91 @112 67 nova numbers matching 327 4 speed 13.6 @ 102mph 70 longhorn c-30 402/4 speed 70 c-10 swb 402, muncie 4 speed 94 s-10 350/th350 3:73 posi 71 c-20 402/th400 towrig for racetruck. 72 4wd lifted on 35's 72 350/3 speed winter beater

12-04-2002, 10:44 PM	#4
Bowed Registered User Join Date: Oct 2002 Location: where it's hot Posts: 1,059	Running with the drive shaft off still makes noise , running with the trans out there is "NO" noise so the clutch and plate must be OK and not hitting any where . The clutch fork and throw out bearing are brand new from when I took it out a couple of weeks ago . There was some mickey mouse work done on the linkage so Im thinking may be some mix and match done on it to cause a problem .



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