So I took out my RTF-8709B transmission and installed a RTLOF-16713A transmission as I have done in all my trucks (44K miles on 9 speed if anyone is interested) and I have a grinding noise when under load between 1400 and 1550 rpms. Rear ends are good, not even a trace of filings on the magnetic plugs. Driveline angles are correct and ujoints are good. New clutch, resurfaced flywheel and bellhousing bolts are all tight. Noise goes away when I hit 74 mph or 1550 rpm. Anyone had a problem like this before. Im blaming the noise on the Cat engine as that is where all my problems in life seem to stem from.
13 speed transmission
- Thread starter jt1980a
- Start date
Could be several things. A dyno will tell you if it is the engine. Some tests can isolate it from the tranny to see if that is the problem. Outside of that, could be a carrier bearing or missing or incorrect location of weights on the driveshaft. In that case, drive shaft would have to be balanced off the truck. That is assuming the yoke and rear end are good.
Another test is a viz check where the truck is put on a machine with probes to isolate where the noise is coming from.
Another test is a viz check where the truck is put on a machine with probes to isolate where the noise is coming from.
purgoose10
Veteran Expediter
Depending on what size Cat could be to much torque for the 13spd. The overdrive gear and bearing in the back of the transmission is a very small gear. They have always given people fits about vibration. Does it also vibrate in direct or just in overdrive??
Are the cluch, flywheel and trans properly alligned cluches plates or flywheel cracked did the machine shop magnaflux the flywheel after machining it? Did you pruge all the old lube from all the U and slip joints? Other than that I think Davekc and Mdbtyhtr covered it.
Bob Wolf.
Bob Wolf.
even though it only has 44,000 miles, that doesnt mean everything is good yet but in this case, everything is like new yet. Motor mounts are good. I was going to change the harmonic balancer just to satisfy my curiosity but it is a fluid balancer and I never heard of one of those going bad, Ever. The trans is quiet until it warms up, usually takes about 10 miles. The trans isnt overheating, it stays at about 220 degrees. I had it out twice and took the top plate off but everything looks like new and is tight. Nothing on the magnets inside the trans. I did install a new clutch (eaton fuller) and I had awful vibrations after that. Dealer Eaton wouldnt give me anew clutch, they said there is no way that little thing on the back of that big motor could cause that problem! What a bunch of morons those factory reps are, do they really drink their own Kool Aid? The dealer wouldnt exchange it either saying that Eaton wont reimbure them. Even though I didnt buy it from eaton, I bought it from the dealer, they still wouldnt stand behind it. Got to love JX Peterbilt? They told me to turn the clutch 180 degrees and try that. To my amazement it worked and the vibrations are minimal. I thought a clutch was suposto be balanced??? How can I explain flipping a clutch 180 degrees would make a difference? Anyway, the transmission still makes noise between 1400 and 1550 rpms. But it is only noticible on the high side of the trans. and really bad in 13th gear. But like I said if I run it above 1550 rpms it seems to be alot quieter but Im also running 72+ mph @ 1550. Should I get a thrid trans and see if that helps or do you guys think it is resignating from the engine? There is a slight engine vibration with truck stopped and clutched pushed in when I rev up to 1500 rpms. I looked at alot of 3126's and they all vibrate, mine really isnt any different.