NV4500 Tranny Trouble

[trbankii]

Reading here and elsewhere, there are some who have added the tranny dampener based on it being a "recommended must-have" and others who haven't added it and see no difference... South Bend said that it is a dealer-only item.

[6.5 Detroit Diesel]

Now that I really think about it, I don't remember putting it in at all. I remember reading up on it, but then deciding that I could do without. Of course if it comes with the clutch kit........

[trbankii]

Might have some info for you, 6.5DD.

Talked to Peter at South Bend Clutch to order my replacement kit. Their kit comes with the flywheel, clutch disc, pressure plate, alignment tool, and throw-out bearing. I asked if there was anything else I'd need or that he'd recommend. He mentioned the tranny dampener again and also suggested replacing the fork and pivot ball - which I said was the reason I was going in there in the first place... He said that it was all pretty straightforward, but that there was one common mistake. He said to make sure that you put the clip and fork into the groove of the bearing together - don't split them apart. Without seeing it first hand, I can't quite picture what he was saying, but he said I'd understand when I saw it. But he said that people commonly split them apart and then have engagement problems.

Having done the replacement, if you can picture what he is saying and didn't keep them together that is likely your problem. Hope that helps!

[RT]

FWIW, I have been into my clutch 3 times. Once to do the rear main, then to do the input shaft seal and lastly to replace the fork, pivot and throughout bearing. Did the pilot bushing once. The disk was replaced at 118K by the PO right before I bought the truck. I am still using the ORIGINAL pressure plate and dual mass flywheel. Truck now has 252K on it. The master and slave blew when the fork/pivot went south. The bleeding process was VERY tedious and I experienced all the issues you are having. Keep working the clutch and try to bleed it. It will eventually start working normally. When the dual mass, etc. finally quits South Bend will get my business. Grease the pivot every time you do the chassis which for me is every 4K. RT

[trbankii]

RT, thanks for reminding me about the rear main seal and input seal - should replace those while I'm in there... Finishing putting my parts order together today.

[trbankii]

Got all my parts on order. The package from South Bend Clutch came yesterday - prompt shipping, carefully packaged, and Peter answered all my questions. I went with the heavy-duty Kevlar clutch - the SM flywheel, clutch, alignment tool, and bearings was under $700 shipped to my door. VERY pleased with the service.

Now just have to wait for the RockAuto and dealer items to get here and clear some time out to work on the truck.

[trbankii]

Talking with the GM parts counter person, the transmission dampener is nearly $500. But he included the TSB that recommends the dampener addition as follows (red, bold highlights mine):

#66-72-02B: MANUAL TRANSMISSION RATTLE NOISE AT IDLE - (Feb 1, 1997)

REVISION: 01/27/97
THIS BULLETIN IS BEING REVISED TO ADD THE 1992-95 MODEL YEARS AND CHANGE PART NUMBERS. PLEASE DISCARD CORPORATE BULLETIN NUMBER 66-72-02 (SECTION 7 - TRANSMISSION). ---------------------------------------------------------------------- REVISION: 02/20/97
THIS BULLETIN IS BEING REVISED TO CHANGE A LABOR OPERATION NUMBER. PLEASE DISCARD CORPORATE BULLETIN NUMBER 66-72-02A (SECTION 7 - TRANSMISSION).
---------------------------------------------------------------------- SUBJECT: MANUAL TRANSMISSION RATTLE NOISE AT IDLE (INSTALL CONVENTIONAL FLYWHEEL)
MODELS: 1992-96 CHEVROLET AND GMC C/K 2-3 MODELS WITH 6.5L DIESEL ENGINE (VIN'S F, P - RPO'S L65, L49) AND NV4500 5 SPEED MANUAL TRANSMISSIONS (RPO'S MW3, MT8)

CONDITION:

SOME OWNERS MAY COMMENT ABOUT A RATTLE OR BANGING NOISE FROM THE TRANSMISSION WHILE THE ENGINE IS IDLING, THE CLUTCH ENGAGED (CLUTCH PEDAL RELEASED) AND THE TRANSMISSION IS IN NEUTRAL. THIS CONDITION IS MORE LIKELY TO OCCUR ON A VEHICLE THAT IDLES FOR PROLONGED PERIODS OF TIME. THIS RATTLE SHOULD NOT BE CONFUSED WITH NORMAL ROLL- OVER NOISE (TURNING BEARING/WHIRRING NOISE) WHICH IS GENERATED WHILE THE TRANSMISSION IS IN NEUTRAL, CLUTCH ENGAGED AND ENGINE IDLING.
CAUSE:

FAILURE OF THE HYSTERESIS DAMPER INSIDE THE DUAL MASS FLYWHEEL (DMF).
CORRECTION:

INSTALL A CONVENTIONAL FLYWHEEL, REVISED CLUTCH KIT AND A TRANSMISSION DAMPER. THESE REVISED PARTS ARE CURRENTLY INSTALLED IN 1997 MODEL TRUCKS.
IMPORTANT: INSTALLATION OF THESE PARTS WILL RESULT IN SOME DRIVE RATTLE (TRANSMISSION GROWL) WHEN DRIVING AT ABOUT 900 RPM OR LESS. NORMAL DMF SHUT-DOWN RATTLE WILL BE ELIMINATED IF THE CLUTCH IS DISENGAGED (PEDAL DEPRESSED), BUT RATTLE WILL OCCUR IF THE ENGINE IS SHUT-OFF WITH THE TRANSMISSION IN NEUTRAL AND THE CLUTCH ENGAGED (FOOT OFF PEDAL). THIS RATTLE IS FROM THE TRANSMISSION AND CAN NOT BE ELIMINATED BY TRANSMISSION REPAIR OR REPLACEMENT.

SERVICE PROCEDURE:

REFER TO THE APPROPRIATE YEAR SERVICE MANUAL SECTION 7C FOR CLUTCH REPLACEMENT PROCEDURES. WHEN INSTALLING THE NEW FLYWHEEL, THE RETAINING RING FROM THE DMF IS NOT USED.
4-WHEEL DRIVE: THE DAMPER IS INSTALLED BETWEEN THE TRANSMISSION AND THE TRANSFER CASE. TO INSTALL THE DAMPER, THE TRANSMISSION REAR EXTENSION HOUSING MUST BE REMOVED. REFER TO THE APPROPRIATE YEAR UNIT REPAIR MANUAL, SECTION 7B8, NV4500 MANUAL TRANSMISSION FOR DETAILS. WHEN INSTALLING THE DAMPER NUT, APPLY LOCTITE(R) 242, P/N 12345493, TO THE NUT THREADS AND TORQUE THE NUT TO 325 LB. FT. (441 N.M).
2-WHEEL DRIVE: THE DAMPER IS PART OF THE YOKE ASSEMBLY. REPLACEMENT OF THE YOKE IS REQUIRED. TO INSTALL THE YOKE, REFER TO THE APPROPRIATE YEAR UNIT REPAIR MANUAL, SECTION 7B8, NV4500 MANUAL TRANSMISSION. WHEN INSTALLING THE YOKE/DAMPER NUT, USE LOCTITE(R) 242, P/N 12345493, ON THE NUT THREADS AND TORQUE THE NUT TO 325 LB. FT. (441 N.M).
IMPORTANT: YOKE/DAMPER NOT USED ON 15,000 LB. MODELS

THE FOLLOWING FASTENER TIGHTENING SPECIFICATIONS SHOULD BE USED: -REAR EXTENSION-TO-CASE BOLTS 40 LB. FT. (54 N.M) -FLYWHEEL-TO-CRANKSHAFT BOLTS 65 LB. FT. (90 N.M) -PRESSURE PLATE-TO-FLYWHEEL BOLTS 25 LB. FT. (35 N.M)
NOTICE: THIS TRANSMISSION REQUIRES A SPECIAL SYNTHETIC LUBRICANT, P/N 12346190. DO NOT SUBSTITUTE ANY OTHER LUBRICANT AS INTERNAL TRANSMISSION DAMAGE MAY RESULT. TRANSMISSION CAPACITY IS 4 QUARTS (3.78L).

PARTS INFORMATION
P/N DESCRIPTION QTY 12375179 '92-95 K L49/L65 FLYWHEEL KIT 1 12375180 '92-95 C L49/L65 FLYWHEEL KIT 1 12375181 '96 K L49/L65 FLYWHEEL KIT 1 12375182 '96 C L49/L65 FLYWHEEL KIT 1 14061685 PILOT BEARING 1 12345493 THREAD LOCK SEALANT A/R 12346190 MANUAL TRANSMISSION FLUID 4
PARTS ARE CURRENTLY AVAILABLE FROM GMSPO.
WARRANTY INFORMATION:

FOR VEHICLES REPAIRED UNDER WARRANTY, USE:
LABOR OPERATION DESCRIPTION LABOR TIME J1420 FLYWHEEL, MANUAL TRANSMISSION-REPLACE USE PUBLISHED K2160 TRANSMISSION YOKE, REPLACE (C) LABOR OPERATION K2764 TRANSMISSION REAR HOUSING, R & R (K) TIME
IMPORTANT: LABOR OPERATION IS CODED TO BASE VEHICLE COVERAGE IN THE WARRANTY SYSTEM.

FIGURES: 0 CAPTIONS: 0

If the only purpose of the dampener is to reduce noise at idle, I think that I can likely do without spending the extra $500 at this time - unless popular opinion is that the rattle is also enough of a vibration to cause durability issues...