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DJCollins · 07-10-2019, 09:18 PM

Last year I foolishly lost my transmission dipstick on a trip. I have a 1999 Itasca Suncruiser 34 ft Diesel pusher. Allison MT-643 transmission. Allison dealer could only sell me a universal one I have to calibrate. If another owner could measure their dipstick for overall length and full hot length it would help immensely. To calibrate I would have to get fluid to over 160F stop and remove a sensor while it’s hot. To get temp that high I have to drive on highway hurry home, pull the sensor to check for fluid but by then it cools down. Idling puts no load on the transmission and city driving it only got to 115F. Thank you all in advance for any help.

Ray,IN · 07-10-2019, 11:15 PM

Your request will get more exposure to other owners with the same MH if you have a moderator move this to the Winnebago/Itasca forums.
If you choose to do that, click the red triangle under your screen name and type your request. The moderators of irv2.com are quite helpful.
I do not know about your Allison model, but most have a feature on the touch-pad to check oil level. With oil at normal operating temperature, transmission in neutral, press and hold both up and down arrows until the indicator screen flashes the oil level.

The procedure will be in your Allison owners manual, if your transmission supports this feature. I have read this feature is quite accurate.

If, in the future, you have any general questions about your Allison transmission, post them in the Allison forum. One of the participants is a retired Allison fluids engineer.

Dav L · 07-11-2019, 06:54 AM

To calibrate, wouldn't you change the fluid / filters in the trans with the specified quarts when warm, let cool down completely on level ground and then slide the too long uncalibrated dipstick in to find out when it touches the liquid. That will set the cold mark. Cut the dipstick a little longer than that and remark the cold. A little higher is the hot. Not sure you have to go through all those gyrations to "accurately" set the hot. It will be easier to get a measurement of the difference between cold and hot on a dipstick from an Allison owner. More pertinent than an overall length from a different RV. Is the uncalibrated dipstick marked for cold / hot? If so, then you are "set".

DJCollins · 07-11-2019, 07:21 AM

Dav L
Thank you.
I had considered doing what your suggesting but from what I found on line for fluid quantities they were complete amount to include torque converter. Draining at the pan will not drain the converter. If I could find the quantity of just system that would work. Also to answer your question the dipstick I got from Allison was a used one with no markings.

grindstone01 · 07-11-2019, 07:28 AM

Look for a used rig like yours for sale locally and compare dip sticks.

dbarton291 · 07-12-2019, 08:10 AM

Dipstick calibration in an MT is a reference line to the split line at the main housing/oil pan. You run a wire down the outside of your dipstick tube, retain it with tape, and mark where the split line is. Lay your blank dipstick next to the wire and mark the dipstick markings on it measuring from the split line. The dimensions are contained in the service manual. That's what you really need.