jauringer
Member
Needless to say I'm a little angry. It's like playing whack a mole. The more work I put in, the more issues pop up.
I'm getting an intermittent slip at the 2-3 upshift. 1st, 2nd, reverse, and kickdown are all fine. It's just 2nd to 3rd. It's happening about 90% of time. It won't happen if I floor it or if I'm going really slow. (maybe I just can't feel it?) but anywhere in between I'm getting about 100-200 rpm climb and then it catches. (is this what runaway is?) it happens very fast and isn't very noticeable most of the time but its a slip. (or runaway if that's what that means)
a little history:
I bought this truck 5 months ago. The po had been driving like a manual because it would shift straight to 3rd gear at 5mph. When I got it home the throttle pressure rod was laying on the bell housing. I obviously repaired it but I have no idea how long it was like that.
2 months ago while driving I had a very large slip occur. They were within a few minutes of each other, it was from 2nd to 3rd, and it took a couple releases of the gas pedal before it caught. It scared the heck out of me so I started doing a little research and read that a transgo tf2 will help firm the shifts up and decrease 2-3 overlap, I installed one last month. (thread in this forum and no, I didn't think it would magically repair damage that already existed, but I was hopeful that it might help keep any additional damage from happening.)
besides the one occurrence I mentioned above and today, the tranny has been acting perfectly normal.
I'm about to go ahead and adjust the bands and change the fluid even though it was just done. Before I crack the pan, I would like to have a plan in place so that I know what I need to look at. Below is kind of an outline of how I'm thinking this through. Any help or corrections to my information would be greatly appreciated.
1. Fluid is brand new , full (not overfull) (B&M trick shift), and is not burnt.
2. Band are adjusted
3. Throttle linkage is adjusted to factory spec. (I did have to go back in and readjust this after tf2 install but it is spec now)
4. Gear shift control linkage is exactly the way it's supposed to be.
5. Stall test @ 1700
6. The rear clutch is engaged at any forward gear so if it was bad I would be experiencing other symptoms.
7. 3rd gear is created by applying the rear and front clutches simultaneously. The front clutch is also applied with the l/r band for reverse. Reverse is acting fine so that leads me to believe the front clutch is not the problem.
8. When governor pressure increases on the 2-3 shift valve, the line pressure is forwarded to the front clutch and the outside of the kickdown front servo. When pressure on both sides of the front servo are equalized, it retracts under it's own spring tension which releases the kickdown band. (2nd gear)
based on the stall test, and lack of additional symptoms to indicated a clutch problem, would it make sense that the front kickdown servo might be the issue here. If it's not retracting properly in it's bore and the kickdown band is not releasing in time. Would that cause a slip/ruanway?
If this all makes sense, what am I looking for in a bad servo? Lastly, monroes torqueflite book states that it makes no sense tearing out a 727 without first doing a pressure test as it May be something that can be repaired in the vehicle. Where would I find the equipment to perform a pressure test? (can I make my compression gauge work?)
any help would be greatly appreciated.
I'm getting an intermittent slip at the 2-3 upshift. 1st, 2nd, reverse, and kickdown are all fine. It's just 2nd to 3rd. It's happening about 90% of time. It won't happen if I floor it or if I'm going really slow. (maybe I just can't feel it?) but anywhere in between I'm getting about 100-200 rpm climb and then it catches. (is this what runaway is?) it happens very fast and isn't very noticeable most of the time but its a slip. (or runaway if that's what that means)
a little history:
I bought this truck 5 months ago. The po had been driving like a manual because it would shift straight to 3rd gear at 5mph. When I got it home the throttle pressure rod was laying on the bell housing. I obviously repaired it but I have no idea how long it was like that.
2 months ago while driving I had a very large slip occur. They were within a few minutes of each other, it was from 2nd to 3rd, and it took a couple releases of the gas pedal before it caught. It scared the heck out of me so I started doing a little research and read that a transgo tf2 will help firm the shifts up and decrease 2-3 overlap, I installed one last month. (thread in this forum and no, I didn't think it would magically repair damage that already existed, but I was hopeful that it might help keep any additional damage from happening.)
besides the one occurrence I mentioned above and today, the tranny has been acting perfectly normal.
I'm about to go ahead and adjust the bands and change the fluid even though it was just done. Before I crack the pan, I would like to have a plan in place so that I know what I need to look at. Below is kind of an outline of how I'm thinking this through. Any help or corrections to my information would be greatly appreciated.
1. Fluid is brand new , full (not overfull) (B&M trick shift), and is not burnt.
2. Band are adjusted
3. Throttle linkage is adjusted to factory spec. (I did have to go back in and readjust this after tf2 install but it is spec now)
4. Gear shift control linkage is exactly the way it's supposed to be.
5. Stall test @ 1700
6. The rear clutch is engaged at any forward gear so if it was bad I would be experiencing other symptoms.
7. 3rd gear is created by applying the rear and front clutches simultaneously. The front clutch is also applied with the l/r band for reverse. Reverse is acting fine so that leads me to believe the front clutch is not the problem.
8. When governor pressure increases on the 2-3 shift valve, the line pressure is forwarded to the front clutch and the outside of the kickdown front servo. When pressure on both sides of the front servo are equalized, it retracts under it's own spring tension which releases the kickdown band. (2nd gear)
based on the stall test, and lack of additional symptoms to indicated a clutch problem, would it make sense that the front kickdown servo might be the issue here. If it's not retracting properly in it's bore and the kickdown band is not releasing in time. Would that cause a slip/ruanway?
If this all makes sense, what am I looking for in a bad servo? Lastly, monroes torqueflite book states that it makes no sense tearing out a 727 without first doing a pressure test as it May be something that can be repaired in the vehicle. Where would I find the equipment to perform a pressure test? (can I make my compression gauge work?)
any help would be greatly appreciated.