Tranny changes, different

[graham]

As most of you know I run dual fuel, LPG and petrol in my Jeep. No major concerns except for the gear shifts when running LPG. 727 Tranny.

It takes alot longer for the tranny to shift gear, from 1st to 2nd or even 2nd to 3rd, when on LPG than it does on petrol.
Shifts great on petrol, no worries at all. Takes around another 1000 RPM to do the same shift, same road conditions, when on LPG :confused:

This is something I can live with, but would like to understand why?

[Lindel]

Graham, the only thing that I can think of, is the way the engine reacts to the load of moving the vehicle. If it's not making as much power on LPG, then it might be affecting the way the tranny shifts. Otherwise, I don't have a good answer for you.

I don't think the 727 uses a vacuum signal to shift with, but uses other means to determine when to shift.

Not that I'm a tranny expert, by any means!! ;)

[ April 08, 2002: Message edited by: Lindel ]</p>

[graham]

<blockquote>quote:</font><hr>Originally posted by Lindel:
I don't think the 727 uses a vacuum signal to shift with, but uses other means to determine when to shift.[ April 08, 2002: Message edited by: Lindel ]<hr></blockquote>

Can any one give more info on this, is there a vacuum shifting devise on a 727?

[J20fan]

Graham,
I am running propane only on my Wag and I have a noticeable long shift as well. The 727 does not use a vacuum modulator but a mechanical shift linkage located on the left side of the tranny. This adjustment is detailed HERE (http://www.ifsja.org/tech/transmission/727adj.shtml). I have used this process to set-up my tranny and did a tranny flush that is described somewhere in the forum I can't find it right now. Basically remove your inlet line to the rad direct into a pail while supplying new fluid through the return line from the rad. Someone else may be able to give you a link. I also replaced filter and adjusted the bands as well. This helped lots with the operation but I cannot seem to get a more comfortable shift. I have adjusted the linkage a small amount to give a signal with less throttle but I am a bit hesitant to go too much so I do not damage my tranny. There are people on the board with far more experience with the 727 than me so perhaps they will have a better plan for this problem.

[ April 12, 2002: Message edited by: J20fan ]</p>

[J20fan]

Graham,
Check this post it has links about flushing and an description Old Post (http://www.ifsja.org/cgi-bin/ubbcgi/ultimatebb.cgi?ubb=get_topic&f=2&t=005729&p=)