Catalina455, DmaxAllitech

[SPICER]

Does anybody have a way to get ahold of Catalina455? He reported a downshift noise from 2nd to 1st that I have. I wanted to find out what his dealer told him.

Otherwise, anybody hear a shift noise while decelerating at exactly 18mph? You must have the windows down and be on a quiet street to hear it clearly, but it sounds like a distinct downshift "click" much like a motorcycle might make. I only hear it when the tranny is warm. Thanks for the help!!! SPICER

[YZF1R]

Yes, I hear the exact same noise. Slowing to a stop 3rd to 2nd. I'm not worrying about it though. Figure it's just a solenoid or something snapping shut or open. Love this trans!

Steve

[Catalina455]

Spicer, the clunk that you described mysteriously disappeared a couple of days after I posted. I didn't take it into the dealer. So far the noise hasn't returned. Give it a couple of days and hopefully it will clear itself out.

You can reach me at canam77@earthlink.net

[dmaxalliTech]

Guess I have never really noticed this noise. If you can get it consistantly, Is it there at certain speed or at downshift? Does it do it in manual gears or manually downshifting?

[YZF1R]

dmaxalliTech: It will do it always when warm. As Spicer said it has to be quiet to hear it. I think it may just be a solenoid or perhaps the drive train slack comes back in just before downshifting and then runs out again when downshifted. Are the ratio's just right between 3rd. to 2nd to do this? I don't know. Maybe this is the "click".
It doesn't really sound "bad" to me, just another quirk or noise from a very beefy drive train. For me, I only notice it when making an easy stop in a quiet place, in automatic mode (never tried it manually), when she goes from 3rd. to 2nd.

Steve

[dmaxalliTech]

Hmm, thats a tough call....A solonoid should if making that much noise should sound in other ranges...drivetrain slack is likely but odd that its taken up at that time..
Drop it in 4 wheel drive and see if it changes pitch or volume..That would help determine driveline or not.

[YZF1R]

I'll have to try the 4X4 sometime. By slack, I was thinking that maybe the engine is pushing the truck right before downshifting and afterwards pulling the truck back, hence the slack run in/run out. Like I said though, it really does not sound like a "bad" sound. Maybe I'm talking something different than Spicer. I know the post he refered to was from 2 to 1, but the speed he mentioned made me think of his sound and mine as being from 3 to 2. I know mine is from 3 to 2.

To me it almost sounds normal. It's a good, not loud, solid sounding click. The motorcycle shifting type sound is a very good example, except even cleaner sounding than that.

Steve

[Gbenzx01]

Well Spicer,
Me thimx it's doing what it thinks you want it todo. 28k mi & mine will still do this if running say 25 drop the power & just let it coast. I t does this abt 20 & more pronounced clunk at abt 5-7mph. You may be able to find on here somewhere with search since I remember the discussion.
At the Allison shop they told me that if I would just tap the brake & sure enough no clack & no clunk. Their say was that if you do not tap the brake it will respond per tow/haul instructions instead of regular downshifts. Now I have no earthly what they are saying but sure enough when I'm thinkin :confused: I'll usually tap for the downshift at abt the right speeds to avoid the above.
But they also say that it cannot hurt anyting so I don't pay much attention toit.
If you have a little time drop by & chat with the Allison people. Most we've dealt with know these transmissions & will not steer you astray.

Gben

[SPICER]

To clarify a little more, for me it feels like it is at a downshift but I do not see any reaction on the tach. I am coasting but slowing down(braking or not, does not matter) and it occurs for me at exactly 18mph. I tried it manually downshifting and heard nothing. However, if I am in reverse going kinda fast and suddenly let off the gas, I hear the same noise only louder, a definite "CLICK!".

The windows must be DOWN and on a quiet road.
Thanks for the replies, most trucks probaby have it but not noticed. Try the reverse thing. It is louder. SPICER

[Gbenzx01]

Now Spicer,

how many gears you got goin backards? :rolleyes:
I wish now to scratch what I said above & grant my undivided attn back to square one wherein Eric,dmaxalliTech had it right with, hmmmm it's a tough call! :cool:
I did some fairly healthy backup runs this afternoon & concluded, you got something I ain't got. Soooo, just hop on over to Eric's place at GR, Mi & betcha you'll know whats what in 5mins or less!
But really may I fire one more shot?
If mine I would certainly have it chkd out; oil in diff & trnsfr case, loose bolts at trans mounts & ujoints(MikeG lost the entire truck cause of ujoints), thats all,

Thnx Gben