I was just goofing around with my Scout. When I picked it up it had no reverse. Well I got the truck started up and sure enough I found reverse. I have to rev the engine then it slams into reverse. Is this something that should be solved with a band adjustment? Once its in gear it seems to reverse fine.
TF 727 question.
- Thread starter 73scoutII
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Michael Mayben
IHPA Tech Moderator - Retired & No Longer Online
Most likely...the low/reverse band is badly out of adjustment! Don't keep forcing it, when it "bangs" into engagement, that is when the low/reverse servo piston will "flop" in it's bore and it's likely to break the cast iron band which means overhaul time!
Thanks for the information. I plan to do the band adjustments this weekend and install another t-case. My friends Dad mentioned trans-x. What should I use as the main fluid?
Michael Mayben
IHPA Tech Moderator - Retired & No Longer Online
My advice, put nothing inside the trans other than plain old dexron (whatever version you can find, it's not critical).
Put no form of "snakeoil" in it (such as that trans-x crap), that stuff will actually damage internally bonded parts (friction materials) and turn any rubber seals and rings to mush. That stuff is shit!
If seals leak, then they are worn out. But most critical is the internal rubber seals that hold hydraulic pressure.
You are probably going to find much debris in the pan and even the filter itself May be partially blocked. Simply clean the pan and replace the filter, that means it's working as it should if it's partially clogged.
Put no form of "snakeoil" in it (such as that trans-x crap), that stuff will actually damage internally bonded parts (friction materials) and turn any rubber seals and rings to mush. That stuff is shit!
If seals leak, then they are worn out. But most critical is the internal rubber seals that hold hydraulic pressure.
You are probably going to find much debris in the pan and even the filter itself May be partially blocked. Simply clean the pan and replace the filter, that means it's working as it should if it's partially clogged.
Appreciate the information. Thank you very much. What do you recommend for the t-case?
Michael Mayben
IHPA Tech Moderator - Retired & No Longer Online
I use plain old 50w straight weight motor oil or as they said in the old days..."mineral oil". That is the same viscosity as 80w-90 gear oil. I'd never run any synthetic in those units as the seals don't like the stuff and I think it's a waste of money myself.
Well I dropped the pan this evening. It was disturbingly clean in there. The sealing faces on the pan and transmission were scratched up pretty good like someone had scraped off some of that liquid gasket stuff or something. I think someone has been in there recently. I did the band adjustment 72 inch/pounds then backed out 2 1/4 turns. Then filled it up till the dip stick read between add and full. Started her up and ran it a little bit in neutral. Then checked the fluid and added again. Did this a few times til I was satisfied, but doesnt seem to have fixed reverse. Looks like I will have to rebuild or find a replacement.
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Michael Mayben
IHPA Tech Moderator - Retired & No Longer Online
Bummer!
So there was no pile of debris in the pan directly under the filter location? That certainly tells me someone has been inside and already done a service. No doubt a big pile of what looks like sand was in the pan, that is the organic friction material that sluffs off from the clutch and band friction surfaces over time.
When you adjusted the reverse band screw, did you have to go "in" several turns or do you think it was pretty close? If it was "close", then someone has already adjusted the band but it's too late!
We need to kick sailor jerry and his sidekick scoutboy74 in the azz so they will git our 727 rebuild video up and running, you can diy this tranny if ya have some patience and wanna learn new stuff!
So there was no pile of debris in the pan directly under the filter location? That certainly tells me someone has been inside and already done a service. No doubt a big pile of what looks like sand was in the pan, that is the organic friction material that sluffs off from the clutch and band friction surfaces over time.
When you adjusted the reverse band screw, did you have to go "in" several turns or do you think it was pretty close? If it was "close", then someone has already adjusted the band but it's too late!
We need to kick sailor jerry and his sidekick scoutboy74 in the azz so they will git our 727 rebuild video up and running, you can diy this tranny if ya have some patience and wanna learn new stuff!
I was clean, no debris. I did have to tighten it several turns. It doesnt even seem to want to go into reverse when I rev it now. Is there anything else I need to do after filling it back up. Does it need to warm up or something to get things moving again?
Scoutboy74
Moderator
You ain't a shittin'!
Craig
Active member
I think john kg6pom nailed it when he said
the normal problem is very hard seals. Too much pressure builds up trying to move the servo with the hard seals, then it suddenly jumps, causing the hard shift.
I have a tf727 rebuilt video, but it not the mm video we would like to have
I assume it still works in drive.
the normal problem is very hard seals. Too much pressure builds up trying to move the servo with the hard seals, then it suddenly jumps, causing the hard shift.
I have a tf727 rebuilt video, but it not the mm video we would like to have
I assume it still works in drive.
I think john kg6pom nailed it when he said
the normal problem is very hard seals. Too much pressure builds up trying to move the servo with the hard seals, then it suddenly jumps, causing the hard shift.
I have a tf727 rebuilt video, but it not the mm video we would like to have
I assume it still works in drive.
Yeah, works fine in drive. I have a friend that will rebuild it for me for price of parts only. Has tons of experience. I just need to drop it. Will have some questions on that. This automatic stuff is new to me. Have swapped a few manuals in my time. I will be hitting you up for some advice and maybe that trans jack after the 18th. Have to leave it in there until then. After that the sucker comes out.
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Craig
Active member
Mm is the world reknown expert on these IH trannies. If you do rebuild it, it might be worth it to send him the valve body and let him do his magic.
This is a service through ihon. Would be nice to get this Scout driveable so you can get it in and out of the garage to work on the body.
Np. On the tool loan.
This is a service through ihon. Would be nice to get this Scout driveable so you can get it in and out of the garage to work on the body.
Np. On the tool loan.
I will look into it. Cost is a limiting factor right now. Until January the available funds for the Scout are limited. I will check with him to see what he would charge to work the valve body. I think I have decided to keep the tranny. I really hope I can get a little assistance in dropping the thing. The whole torque converter thing is a mystery to me. The painting and moving it is a secondary thought at this point. My goals are to get it drivable before January so I can spend my money on suspension and axles.
Michael Mayben
IHPA Tech Moderator - Retired & No Longer Online
I think john kg6pom nailed it when he said
the normal problem is very hard seals. Too much pressure builds up trying to move the servo with the hard seals, then it suddenly jumps, causing the hard shift.
I have a tf727 rebuilt video, but it not the mm video we would like to have
I assume it still works in drive.
Not a true "diagnostic" at all.
How do rubber seals "dry" when they are immersed in oil? Neither do they "swell" from exposure to the working fluid.
How can "too much pressure" build up when the pressure is regulated by the valve body?
If a servo piston is "sticking" in it's bore, then it's because it has flopped previously (abnormal condition) and the bore and/or piston are distorted/damaged.
So any common reason why the band adjustment wouldn't have helped my reverse problem?
Craig
Active member
I can bring my tranny jack over and we can just drop the t/c and tranny as one. You will need to open up the tunnel cover to disconnect the shifter. Plus take the tranny inspection cover off. (the plate that covers the flywheel) and disconnect the drivelines. You get all that done and we can get the tranny out one day after work. 
I can bring my tranny jack over and we can just drop the t/c and tranny as one. You will need to open up the tunnel cover to disconnect the shifter. Plus take the tranny inspection cover off. (the plate that covers the flywheel) and disconnect the drivelines. You get all that done and we can get the tranny out one day after work.
Sweet.... Beer and bbq are on me. Hope you like good beer!
Michael Mayben
IHPA Tech Moderator - Retired & No Longer Online
Most all of the friction material on the band is missing!!