Transmission Shudder Problem

[MasterChief]

I have a problem with the initial engagement of my transmission on my motorhome that has a Freightliner 2004 XC Chassis, a 330 Cat, and an Allison 6 speed 3000MH transmission.

This occurs on initial startup after the motorhome has been sitting idle for 24 to 36 hours. Starting procedure: key on, check gauges, start engine, air pressure builds up to normal, all alarms off, idle speed 700 rpm, all gauges normal, foot brake held on while emergency brake is released, gear selector pad pressed from neutral to drive - the motorhome will shudder for a second or two.

After that, is it runs smooth as always. All starts after that are normal - no shuddering on start (until the motorhome sits again for a day or more)

The transmission control unit has been changed and reprogrammed twice. The transmission has been changed, and the motorhome still has the same problem.

This first started happening at about 30,000 miles.

Has anyone else experienced this or know what this problem might be?

[Flagelpater]

Stab in the dark. What happens if you first select Reverse? Sounds like you have already covered everything that moves!

[MasterChief]

I tried selecting reverse first as you suggested - unfortunatley, that also produces a shudder. Thanks for your reply - it was worth a try.

[wa8yxm]

Other than check the transmission fluid level and take it in for routine tranny service (flush, new filter, fill) I can think of nothing

Shudder is caused by (normally) one of two things

The first thing is low transmission fluid, as the torque converter re-fills from the sump (pan) it may shudder a bit.

The other things is failing clutches

The first is easily fixed
The second... Not so easy