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Topic: Cat 3208 / ORED torque converter noise between 3rd and 4th gear? (Read 406 times) previous topic - next topic

Cat 3208 / ORED torque converter noise between 3rd and 4th gear?

Another question for you guys: my Cat 3028 is pretty quiet and a smooth runner. The only exception is when in third gear between 2400 rpm and 2500 rpm (right before it shifts into 4th). At that time there is a loud, for lack of better term, harmonic imbalance that comes from the back. It sounds like a really loud fan humming and right before the shift into 4th, it lets off and briefly re-engages again before going silent... it sounds like a clutch maybe.

The radiator fan is direct drive, so if it were that I would expect it to exhibit the same behavior in 4th gear but it does not. Could it be the torque converter? Drive shaft needs rebalancing? Any one else with a Cat 3208/Allison combo experience this? There's no noticeable change in performance...shifting remains smooth through out; it's just noise.
1987 Grand Villa ORED
2001 U320 4010

Not all that wander are lost... but I often am.

Re: Cat 3208 / ORED torque converter noise between 3rd and 4th gear?

Reply #1 –
Do you have the side radiator? If so the transmission has a different sound when shifting than the 250 hp rear radiator.
previous 1984 35 ft ORED 250 HP 3208 Cat       
previous 1998 40 ft U295 CAI 325 hp Cummins
previous 2003 40 Ft u320 build #6140 450 Cummins M11.                                                         
1999 Mazda Miata
Ron, Nancy, Tipper the cat, Max The dog
1997 U 270 36 ft build number 5174 8.3 Cummins

Re: Cat 3208 / ORED torque converter noise between 3rd and 4th gear?

Reply #2 –
 
Quote from: red tractor –
Do you have the side radiator? If so the transmission has a different sound when shifting than the 250 hp rear radiator.
I have the rear radiator
1987 Grand Villa ORED
2001 U320 4010

Not all that wander are lost... but I often am.

Re: Cat 3208 / ORED torque converter noise between 3rd and 4th gear?

Reply #3 –
Mine only hums a bit at 68 mph. Diff whine .
Might change trans and diff oils ?

Re: Cat 3208 / ORED torque converter noise between 3rd and 4th gear?

Reply #4 –
Quote from: Protech Racing –
Mine only hums a bit at 68 mph. Diff whine .
Might change trans and diff oils ?
Yea all new fluids are going in before our first trip. Maybe that'll do it.  Need to get the U320 sold before I really start digging in though
1987 Grand Villa ORED
2001 U320 4010

Not all that wander are lost... but I often am.

Re: Cat 3208 / ORED torque converter noise between 3rd and 4th gear?

Reply #5 –
Quote from: Elliott –
The only exception is when in third gear between 2400 rpm and 2500 rpm (right before it shifts into 4th). At that time there is a loud, for lack of better term, harmonic imbalance that comes from the back. It sounds like a really loud fan humming and right before the shift into 4th, it lets off and briefly re-engages again before going silent.

Elliott, you really need to stop worrying about this.  All you have so far is a noise you heard.  Just what do you think a clutch sounds like?  If the tachometer didn't start heading for the sky, it's not a clutch.  If you're worried about the clutch, lift off during the shift and give the clutch(es) time to fully engage.  I have about 10 years on a motorcycle clutch that was slipping because of the wrong lubricant being used. BTDT.
1992 Foretravel Grand Villa
U225 SBID Build No. 4134
1986 Rockwood Driftwood
1968 S.I.A.T.A. Spring
1962 Studebaker Lark
1986 Honda VF700C
1983 Honda VF750C
Charlie, the Dog was broken out of jail 24 Oct 2023
N1RPN
AA1OH (H)e who must be obeyed.

Re: Cat 3208 / ORED torque converter noise between 3rd and 4th gear?

Reply #6 –
Quote from: Protech Racing –
Mine only hums a bit at 68 mph. Diff whine .
Might change trans and diff oils ?
Changed both. Transmission oil was nice and clean, diff oil was sludgy as hell and about a gallon low. Not even a fleck of metal on the magnet though, thankfully. Hoping it was indeed the diff and this clears it up because everything else under there looks tight and relatively well cared for. We head to Vegas at the end of the month and I'll know then one way or another.
1987 Grand Villa ORED
2001 U320 4010

Not all that wander are lost... but I often am.