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Post by mexgrizzly on Oct 30, 2009 1:52:30 GMT -5
So the JBweld on the rear portion of the AX-15 case held up for a year including a trip to Rausch and a trip across the country with a trailer (GCVW=6400# at the truck scale). The jeep had been marking its spot for a few weeks. The old AX-15 had 170,000+ on it so I decided it was time for a younger one. Decided to upgrade to a NV3550. A rebuilt one was only a few buck more than a junkyard one so I went for it.
The first one arrive on Oct 16 and was promptly put in that afternoon. Installed a new clutch while I was in there, throwout bearing was rusty and grooved. Couple of minor hiccups, needed bolts for the shifter tower and a reverse switch. Off to the junkyard for the switch and the hardware store for the bolts. I ordered an NV3550 shifter from Advance Adapter but the AX-15 shift fit on the tranny and I like the location of the shift knob better. Test drive and the tranny is whining a lot in 1-3 and 5, doesn't shift that well for rebuilt, rattling noises in 3-5, really loud rattling noises at neutral throttle in 3-5 gear (neutral throttle => not accelerating, not decelerating). Call rebuilder and they are sending another one, which arrived today. Tomorrow will be another day under the jeep. I hope this one goes well, though I get faster at the tranny change each time.
The jeep has a '92 Cherokee engine and a Novak adapter between the tranny and the D300.
-Andy
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Post by DOUG® on Oct 30, 2009 6:30:04 GMT -5
Not saying the noises you hear are normal, but the 3550 is a very noisey transmission anyway.
The one in the Rubi has made noise since new, took it back to the dealer twice, both times they took me for a ride in other Jeeps equipped with the same tranny and they both made the same noise as ours.
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Post by ZAEDOCK on Oct 30, 2009 8:43:14 GMT -5
...doesn't shift that well for rebuilt, rattling noises in 3-5, really loud rattling noises at neutral throttle in 3-5 gear (neutral throttle => not accelerating, not decelerating)... Andy, the NV3550 is very picky about fluid. I recommend Pennzoil Synchromesh (IIRC, also has a Chrysler part # on it). Rough shifting happens without it. People say the 3550 is somewhat noisy (have one in my buggy build), but compared to my SM420, I think it's pretty quiet. While "gear noise" may be normal, not even my 420 rattles in gear when driving. Your 3-5 rattle may be the shift fork. Hopefully the replacement is better. Let us know how you make out. Good luck. |
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Post by mexgrizzly on Oct 31, 2009 1:40:21 GMT -5
I had heard the NV3550 is noisy especially at idle. If it was just noise I would just live with it, the other symptoms tell me something else is wrong.
New tranny went in OK, only a few minor glitches, normal. This one shifts better and doesn't whine was much (whining seems normal/tolerable). I used Pennzoil Syncromesh 2 weeks ago and yes it does have the Chrysler part number cross reference on the side. This time I tried royal Purple Sycromax, which lists the NV3550 under the company web site.
I am still getting the rattling/vibration in 3-5 at neutral throttle. I suspect I have some other issues in the driveline. here is some more info:
-I do not get the same noises when driving in low range, 1-5 gear sound normal. There is a little whine I think is normal for the 4:1 t-case.
-The rattle sound (it sounds kind of like a loose shaft wobbling on it bearing) is similar in 3 and 4 gear. 5 has a rattle but is smoother and don't feel as much vibration. This seems to indicate the tranny. The noise in 3-4 seems to be speed dependent, for a given speed above 35 mph this noise sounds the same in 3 and 4.
-I put the rear axle on jack stands and ran it idle in 4th gear. There is a random snapping/popping sound that seems loudest at the pinion of the 8.8. I heard the same noise in June but it is worse now. In June when the diff was open the spider gears seems looser than normal and the pinion shaft had a little play in it; the pinion and carrier were tight. I can sort of hear the noise faintly coming from the tranny but the noise seems like the noise being transmitted up through the driveline to the tranny.
-In September I was trying to figure out the noise and had 4WD Parts Service look at the drivetrain. They opened the rear diff and said everything looks fine; I have never been completely comfortable with this analysis.
-I am planning to remove the rear driveshaft and test drive the jeep in front wheel drive tomorrow. I think I tried this last week but don't remember coming to any conclusions. I replaced a worm u-joint in the front driveshaft today so I may get more conclusive results.
Thanks for the comments,
-Andy
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Post by mexgrizzly on Nov 5, 2009 15:24:05 GMT -5
On Monday I took the jeep to an independent 4WD shop. He still thinks it is in the transmission but suggested I take it to a transmission/t-case rebuilder to get his opinion. He couldn't go for a test drive but based on my description of noises etc, he thought it was the t-case. The shop does free inspections so I took the t-case out and brought it down to him on Tuesday morning. The shop said the inside looked perfect.
Based on on-line research there is some feeling that a longer input shaft is needed on the t-case when connecting a D300 to a NV3550 using a clocking ring. I talked to Advance Adapters and they said the longer input shaft is recommended for proper spline engagement. Advance adapter recommends the spline engagement be 1.5 times the diameter of the input shaft. The input shaft is aproximately 1" in diameter so 1.5" of engagement is recommended. I have approximately 7/8" of engagement. Although the local transmission doesn't think the input shaft could cause the vibration, I decided to have it put it to avoid future issues with breakage. The AA adapter should come in today and be installed this afternoon. Hopefully by friday I will have the jeep back. I also have another name of a guy who is an expert in driveline noises/vibrations/issues.
-Andy
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