slugish 4th gear

[aragu36]

I just changed trans fluid and filter and 4th gear seams slugish on hills
any feedback

 

[aragu36]

I just changed trans fluid and filter and 4th gear seams slugish on hills
any feedback

 

[vicsryd]

MT 643 is a 4 speed and 4th gear is 1.00:1 ratio, no overdrive. Only thing I can think of is the lockup torque converter isn't locking up. I don't have any direct experience with this behavior in an Allison but in my old GMC truck the torque converter stopped locking up when the transmission fluid was low and started foaming.

You might try driving it, getting the tranny up to temp and when you feel like it is being sluggish then pull over and check the diptick for both level and any signs of foaming.

There is quite a bit of documentation available for the MT 643 on the Allison web site available here. Unfortunately, all the troubleshooting documentation, including a video, cost $$ to download.

 

[Pubtym]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by aragu36:
I just changed trans fluid and filter and 4th gear seams slugish on hills
any feedback </div></BLOCKQUOTE>

First question: Did you recheck that the correct tranny fluid and filter were installed?

 

[vicsryd]

This specs says its 18 quarts.

 

[hondo12]

I do not have any machanical knowalge about your transmission, but reading you post about 18 quarts to refill, reminded me that I did read in my allison manual that the initial fill was 17 or 18 quarts but when changing oil the amount to refill was 12 or 13 quarts? as all the oil could not be drained through the plug, again just a hunch, check your dip stick when hot.

 

[aragu36]

thanks
i went to the allison dealer and he told me to get it up to temp and pull off the
lock up solonoid its just above the pan and thats the right level
im a litte weary but it seems my dipstick is way off im getting no reading with 18 qts



thanks for the help

 

[aragu36]

as for the filter i did it myself and bought the parts from the allison dealer