Not Shifting into Reverse?

[colnago]

I have a 352 with a C6 behind it (not original, but it came with the truck when I bought it). Today, I had a 3-hour drive, with stop-n-go for the last 20 miles. When I got to the parking garage, it wouldn't engage Reverse. Great! Just what I needed in a parking garage! $&%^#*@! By the time I left (30 minutes or so), things had shifted or cooled enough to let it shift into Reverse.

It's always had a "hard shift" into Reverse. It also shakes a lot when in Drive at a stop light. Is this an indication of needing a rebuild? A loose/worn band (or bands)? Improper torquing from a previous rebuild? A filter needing replacement? Any clues?

Thanks,

Joseph

[michael69]

If it was the first time and then after it cooled off and then worked as normal with no slipping. I would change fluid and filter and add a good size trans cooler to the front of the radiator to help keep the fluid cooled down. You can get a nice sized cooler at any parts house for around 40 bucks.

[Donnie]

Hi, how is your shift into 3rd ? is it soft or late under normal throttle? My reason for asking is: rev & 3rd share the same clutch pack..
There is another set of clutches for Reverse , no rev band in this trans, only 1 for second. Vacuum leak could cause a Rough idle.. But would also cause late & firm shifts....The reason I need to know about 3rd quality shift is the rev/3rd clutch is in the front of the trans while the rev clutch is all the way to the rear,,The front clutch, rev/3rd, must apply before the rev clutch or you will have a harsh reverse..the timing is close on these 2 units applying. I suspect a soft 3rd as the most likely suspect, but the long trip & the loss of rev does raise some doubt...
Tell us more about the above questions & someone will get back to you.......there are others on here who are transmission men besides me..

Give us more info & ask any questions & we will help you...............Donnie

[colnago]

Donnie,

As I recall, my shift into third can be pretty harsh, especially when it's cold. Usually, the truck stays in town, and the longest drive I have is 10 miles to the dump. So, this three-hour trip was a chance to see different behavior from the old girl. Other than not shifting, she drove like a dream. I might have to put a thermal wrap around my starter (finicky about starting after driving 130 miles, then stopping for gas), and a phenolic spacer under my carb. But that's part of the experience driving a 45-year-old truck!

I'll have to check for a vacuum leak on the tranny. I replaced some fittings and checked lines last year, but it's easy to disconnect the tranny from the intake, and see if it behaves any different.

Thanks,

Joseph

[Donnie]

Joseph, I must admit, I am a bit stumped on this one...Usually after the fluid gets hot it will soften the seals on the piston that applies the clutches & work better... Cold delay complaints are a LOT more common...Did it just do it this ONE time & has not repeated? How about when you got home, did the condition re-occur? Are all the grommets in your linkage tight ? Can you feel the detent in the trans click into place if you hold the shift lever up toward the steering wheel....Try this to make sure that your shift lever detent in the column & the detent in your trans are in synch. LIKE NO LOOSE OR MISADJUSTED LINKAGE.......I'm sure that you have qualified that, but thought that I'd mention it..

There may be a "no reverse when hot" listed in the trouble shooting manual, but it has been years since I have seen that manual, Or experienced that condition
Bobby Ford, may chirp in with a suggestion............or someone else................Donnie

[68 Ford Stepside]

In the Ford factory service manual, section Trouble Symptoms & Probable Trouble Sources it doesn't mention whether the trans is hot or cold. It states no drive in reverse only, the probable trouble sources are=

Fluid level
Manual Linkage
Low Reverse Clutch
Perform Air Pressure Check
Reverse Servo
Valve Body

[BobbyFord]

Yeah, I've got no suggestions other than check fluid level and condition. Burnt fluid = heat and most likely an indication of clutch pack slippage.

[colnago]

Well, I had interesting behavior today. This morning, temps were ~31 degrees; cold enough to be hard to start, but not cold enough to be a major issue. I live in the middle of a neighborhood (lots of stop signs before I get out to a "real" street), so I usually have enough time for the engine to heat up before I need to scoot into traffic. But today, when I got out into traffic, she wouldn't shift into third. She finally did, but at the next stop light, wouldn't shift into third again. I dropped my daughter off at school, and while in the parking lot, I shifted to reverse (clunk), then drive (clunk), and she was fine after that.

At lunch time, it was the same thing. I did have time to check the fluid level (warmed her up, put the tranny in neutral, checked the level). It was right above the bottom "add a quart" line. So, not extremely low fluid, but certainly needing a bit more. I will pick up a quart tomorrow, and see how that helps.

For what it's worth, I have a hard line coming out of the modulator, then about a 6" flexible line up near the top, then back to a hard line, and to the intake manifold. The flex line is fairly new, and looks to be in good condition, so I don't have a reason to think it's bad or leaking. I did read up on the internet, and saw some suggestions that my modulator may have gone bad. I don't have a real reason to think that it might have (other than the tranny not shifting), but I can check that on Saturday.

Thanks for your input,

Joseph

[Donnie]

Hi, I would fill the trans, just in case someone along the 45 year old trail installed the incorrect dipstick.. I doubt that this is your problem, but it is the easiest to rule out. The fact that it would not shift into 3rd twice is leading me to the rev/hi clutch pack...If the fluid smells burned or is off color, suspect the clutches, if it is red, suspect the seals on the piston that applies the clutch pack....If you are getting a bang into rev., that tells me that the rev/hi clutch is not coming on fast enough allowing the complete drive train to continue to spin & when the lo/rev. clutch applies...EVERYTHING stops & the .030 here & .045 there & all clearances in the drive train are giving you this harsh rev. apply........
Also the pressure is higher in rev, so that will compound the harsh shift....If you have 3rd after applying rev, it could be that the extra pressure in rev was enough to stroke the rev/hi piston and some residual oel may remain in the drum & allow 3rd to happen.
The modulator reads the engine vacuum & tells the trans what the engine is doing, the gov.reads the road speed & tells the trans what speed you are going...E.G. when the engine is working hard the vac is low so the trans will not shift until the gov pressure(road speed) overcomes the vac. signal, or pressure. That is why when you let off the throttle, the vacuum is high & a shift will occur.
.........the modulator has control of both shifts, if your 1/2 shift is on time & the 2/3 is late or IYC, missing.. pretty much rules out the mod.
Your symptoms are leading me to think that you may have a problem in the rev/hi drum...Hard rubber seals or worn clutches, or worn rings on the pump support where the drum rides..
One thing that I failed to ask : do you know how many miles are on this trans ? A WAG is ok, if you have a clue...May be helpful ........... Are you using type F or Dex in this unit...Has it been rebuilt? Do you do your own work or have a place where you can be warm & drop the pan?
Donnie

[colnago]

Donnie,

Sorry, didn't mean to ignore you. WIth Christmas shopping, I've been losing "laptop privileges" so the little lady can do her shopping. Okay, back on task.

I don't know the mileage on the tranny, but the truck has 108K. I don't believe the engine is original (some of the castings have car numbers), and I know it did not come stock with a C6. I don't believe it has ever been rebuilt, but the fluid I have seen is clean. I'm using Type F ATF. I don't have a work place, so it's the drivway for me.

The last couple of days, when I start out in Drive, the tranny isn't shifting out of first, even if I take my foot off the throttle. If I shift to 2, it will up-shift, and seems to hold it if I go back to D. Once it warms up, and starts behaving, the shifts are very smooth, until it really warms up, then they're pretty rough again.

Since it's not shifting out of first when cold, I'm beginning to think it has a stuck/clogged valve. I probably need to drop the pan and refill with new tranny fluid. I don't think it's my modulator. A friend recommended taking it to a shop and having them flush the system out, so it gets any/all crud that could be in the system. I'm hoping I can get away with just replacing the ATF in the driveway.

So, that's where I'm at tonight. Temps are dropping, and the breeze picked up, so it should be a miserable weekend! Won't have a chance to touch it until Sunday afternoon, but keep the ideas coming.

Sorta off topic, but how difficult is it to drop a tranny and re-install in the driveway? I have a second C6 at the side of the house, and I was planning on rebuilding that one and doing a quick weekend swap in the spring. Maybe I can't wait that long!

Joseph

[Donnie]

Hi, 2wd.....not hard to change, just heavy...on your back in the driveway in cold weather...I don't know????? What state are you in?
If you do drop the pan, the filter is just a screen & can be cleaned...I am not aware of your skills, but the screen has 1 screw that is longer than the rest, watch where comes from....all the rest are the same size 5/16 .........& if you are able to drop the valve body, and have an air compressor, I can tell you how to check the clutch packs with air & a rubber tipped blow gun....................not hard, but in the cold & on your back????????????? : if you are not getting a 1 / 2 shift now your mod could be acting up,,broken spring or vacuum leak....when you shift into 2nd manually the oel is routed thru diff. passages in the valve body, directly to the 2nd band,,,Can you get all 3 gears shifting by hand???/

Let me know if you tackle it....................good luck, Donnie