Transmission slipping in Drive but not Rev. Help

[The_Handier_Man1]

From: 72Dave  (Original Message)
Sent: 10/25/2006 7:34 PM

My 72 Indian w/ 413 and 727 trans (i believe) is slipping in drive, 2 and 1. It will not move at all unless I really hit the gas and then it finally engages and goes fine after that until I stop again. It engages immediately in reverse so this confuses me.

I just changed the trans fluid today, w/ new filter and pan gasket and drained the torque conv. It still does the same thing. What can I do? The problem is that I really wanted to use it this weekend but have not had the time to work on it as it is stored approx 1.5hrs from my house. I am willing to make another trip friday morning to try adjusting the bands or something else. All help is appreciated.

Thanks Pharaoh for your tips before I re-enlisted. 


From: Slantsixness
Sent: 10/26/2006 11:15 AM

I'm thinking the front pump, behind the torque converter is leaking, but... TRY this...

Check the Transmission cooler lines and cooler for constriction, blockage. you can bypass the cooler and lines completely by attaching a hose form the inlet to the outlet on the trans. If it goes in gear and does NOT slip when bypassed, then the problem is the cooler, replace all lines and use an auxiliary trans cooler instead of te one in the radiator.

second, if the fluid is brown, or burnt, the filter may be clogged. you might just get lucky and change the fluid and filter and all is well.

Last.....but certainly not least!
Did you adjust the transmission bands in preparation for the trip? if you did, you could have the band adjustment set too tight (way too tight!), which would be similar to driving a car with the parking brake still applied!!

The 727 trans is VERY reliable, and the biggest problem with them is Pump failure from overheating, because of cooler restrictions, clogged cooling lines, and/or improper band servo adjustment. These things are pretty much the only things that will "kill" a 727. There is normal wear and tear items, like the bands and soft components, but pretty much the trans is bulletproof... really.
when I say the transmission, I am not including the torque converter in the transmission diagnosis, but it can be a problem... but a costly one.... if the transmission goes into reverse correctly and does not slip, it's very unlikely your torque converter is at fault....

By the way.... a couple jackstands som manual labor and 2 hours you can have the trans out and on the ground. takes only 2 hours to put one back in, too.. on a Class A Motorhome chassis, that is.... Class C's don't count, they take about an extra hour both ways.

Been there...done that...

Tom



From: Slantsixness
Sent: 10/26/2006 11:23 AM

Here's another important question:

Did you get the filter put on right? it will bolt on with two out of three bolts "backwards" and that would cause the pump supply to run dry....

But it sounds like you really have a leaking (internally) pump or blocked cooling lines.
 

From: 72Dave
Sent: 10/26/2006 12:33 PM

Tom,

Thanks for your reply. I did not adjust the bands as I do not know how too or really what they do. My question is - will the bands cause the problem I am experiencing? If not, I do not want to drive a 1.5 hrs one way to check this, at this point I should be making preparations to pull the tranny. If the bands will cause this, what is the procedure for adjusting and I understand there are 2 only, 1 inside and 1 outside the pan. Do I need to go back inside the pan?

Thanks for all help. 
   

From: Slantsixness
Sent: 10/26/2006 1:55 PM

since you had the trouble before you did the filter, and the fact that it still has the same symptom, I doubt seriously that it would be the band adjustment.

Now if it had been sitting quite a while, I might think one of the band servos could be sticking or the valve body is sludged, but I think moer that the cooling and cooling lines are blocked or restricted. Short of that, it's time to pull the tranny.
   


From: 72Dave
Sent: 10/26/2006 2:29 PM

It likely has only been driven 150 miles in the last year. And the problem occurred once when I tried to move it and apparently the fluid was low then I filled it and it was fine but then occurred on the next trip and has gotten worse in the last 2 trips which were in March and April and where only 20 miles total so I do not worry too much but now I want to go further.   


From: DaveB_D27CU
Sent: 10/26/2006 6:25 PM

The 727 is a great trans, a band adjustment is always a good idea if you have some time on it.

If this is something that just started what I would do is look at the basics.

1 - Make sure the fluid is unburnt and at the proper level. You changed the fluid so I will asume that this is correct).
2 - Look at the trans shift down linkage. See if it is rusty or a bugs built a nest. Make sure that it moves freely. I live on a dirt road and mud packs up around the kick down lever and causes a very high and messy up shift. Clean up the mud so the lever moves freely and the trans shifts fine.
3 - If the above is ok then I would be looking at a band adjustment.

Good luck

DaveB