a4ld delayed shift into drive and reverse

[Maniak]

I've seen the messages with a slow engagement into drive, but I haven't seen one for a slow engagement to drive AND reverse.

Once it engages reverse or drive, everything seems normal or than the shift to drive and reverse is a little harder than I remember (even when it seems to be shifting normally)

Anyone know what causes that?

I'm ok with dropping the pan and the valve body, but a complete rebuild I dont' think I'm up to doing myself yet (but If I have to, I have to).

This is on a 1992 XLT with 50k miles since the last rebuild.


~Mark

 

[TPLYNCH]

Seach for a thread by OperaHouse referencing "low/reverse servo" problem.

 

[SteveVB]

Mark,

The delayed engagement could be main pressure problems, also could be linkage, fluid level, dirty filter.

The sealing problems have been discussed for the reverse delay problems. There is also a VB modification to reduce the reverse delay. But if you have both forward and reverse I doubt thats the problem. Main pressure - pump or valve body problems.

Boost pressure valve (bore 208) could be worn- seems to be a common problem in Fords. One guy I talked to about the trans suggested the Boost Pressure valve be replaced as a matter of course. Sonnax has a few valves available, and some tooling avail to recondition the bore if a new valve doesnt fix it.

I have the test procedure for the boost pressure bore - involves removing the vb and compressed air to test.

I would get the pressure readings first see what shows up, then pull the pan to get the filter and fluid changed, pull the vb do some checking, and go from there. Seems like the least amount of cost/ work to check the VB before writing it off for a rebuild.

If you are thinking about doing any work on the trans - order the ATSG books A4LD and the update.

 

[Opera House]

Just when was that rebuild?

I think by about 97, the rebuild kits started to come with the double lip O ring for the low/reverse servo. That and the rust of your seals shouldn't be bad yet. Did this start to happen in a short time or gradually? Is it better when it warms up or it happens any time you change directions? Low pressure could also be caused by loose valve body bolts.

Do you remember your old high school physics course when they talked about static and dynamic friction? The forward clutch engages in any forward gear and stays engaged till you put it in neutral or reverse. Dynamic friction is lower than static, so once it finally engages and holds it takes a lot more force to get it to slip again.

 

[Maniak]

I do seem to remember a week or so again that in the morning when I left for work that it took 1 full second to engage.. which I wasn't sure if was normal...

but yesterday it outright just did it.. I started the truck to go home.. and it didn't go into gear... I then put it into park.. hit the throttle.. put it back into drive and it engaged...

this morning I started the truck put it into reverse.. nothing happened.. I tapped the throttle (to bring the rpms up to 1300 or so) and it engaged.. then it was fine..

On my way to work I stopped (once the tranny was warm) to check the fluid... it was way over full and I saw bubbles in the fluid... so I disconnected a hose and removed some fluid (I know the truck will stink like tranny fluid this afternoon)..

I got it lower.. but it still reads a little high.. (I'll check it when I get home)..

the fluid did look dark, but didnt' smell burnt...

The last thing I did to the truck was change my external tranny filter (which has been on for a few thousand miles but I changed it last weekend).. when I changed it, I added 1 quart of tranny fluid.. its possible that I was already over full and adding that 1 new quart when I changed the filter just put me way high.

Once I warmed up the truck it didn't have the problem.. I even turned off the truck for a few minutes.. then started it.. and it was fine.. While it has the problem drive or reverse won't engage.. but once I get one engaged it works fine.

ok.. stupid question.. where do you think I can get an atsg book in town? or do you think that is a mail order type thing only?

I'm all set to change the tranny filter (internal.. and one off a 97) and fluid this weekend... so I would like to do any tests possible while I have the pan down.

~Mark

 

[Opera House]

Just get it

from www.bulkpart.com With the shipping only $7.50 it will be paid for by what you save on the filter. I would also get the two double thick valve body gaskets. This is only indicated by the higher price. Their new site has gone to crap since many descriptions have been just truncated and they eliminated a bunch of pictures. Please complain. Remember you have to order the pan gasket seperately and O rings seperately (if not transfered). Use the new hardware or the filter will drop down. Sounds obvious but it has happened to a few people here.

The bubbles are interesting. Did you take the filter apart? Wondering if increase in level could be coolant. This is also what happens when the filter sucks in air.

 

[SteveVB]

Well if you didnt over fill with the filter change I would most certianly look at the cooler in the radiator.

I looked for the books local and they wanted like $50 each- they were 15 or 17 online. If you are pressed a library may have them, or the Ford manual. If you have the FSM - the one I have has a reprint of the main manual- no update.

I just got a bunch of stuff- filters O-rings, shift kit, gaskets from Bulk parts (Makco Distribution) it came in 3 days.

 

[Maniak]

I double checked the fluid last night.. I don't see/smell any antifreeze in it.. so I don't know what i was thinking when I changed the external filter.. I should have checked how much fluid was in there first... The only thing I can think of is that each time I replaced the filter I added 1 quart of fluid.. As of yesterday I had 2 quarts too much fluid in there..

So I took out 2.5 quarts yesterday.. then added 1/2 quart back to get it to read in the correct spot.

This morning it did it again, but nearly as bad... When I put the truck into reverse the rpms came up some, then it engaged...

I have noticed that it will only do the problem when the tranny is cool.. For example, last night after letting it sit 1 hour, it did not do it.. but if I let it sit all day (like while I'm at work or first think in the morning) it will have the issue.

I have access to a pressure gauge so I am going to see if I have low pressure. If so, I'm going to bypass my external filter to eliminate that.

Do you think I should replace the low/reverse servo, and replace the VB gasket when I change the internal filter to the 97+ version?

~Mark

 

[Opera House]

You didn't say what year

it was rebuilt, how long this has been happening and if any work was done prior to the occurance. Probably the seals aren't in that bad a shape unless they were put in backwards. The stuff I said to order is cheap and you might as well get it all at once and save shipping. I have always believed that a lot of problems are simple stupid obvious things. I would drop the valve body as a matter of course if no problem is found with the filter or the valve body bolts.

Foaming can cause a lot of problems with pressure. Certainly 2 over is a lot of fluid. It should stop foaming.

 

[Maniak]

It was rebuilt @ 236k miles.. (its at 281 now).. that was just over 1 year ago...

Before that was @ 186k miles...

I know why it went @ 236k miles.. I overheated the motor bad and cracked both heads and melted some hard parts in the front of the tranny (I lost a water pump and all the water and didn't know until I smelled the motor being hot).

ok.. so my plan for this weekend is to change the following:

external filter (just in case)
internal screen (replace with a 1997+ filter with hardware and oring)
Valve body gaskett (double thick kind)
Low/reverse servo
fill with new fluid.. but don't over fill it..

~Mark

 

[Opera House]

You don't take pitty on a car do you

Putting 50K a year on a vehicle over 200K. Does this have a good tranny cooler on it? Probably still has the factory pump in it. You should have told us that earlier. There are a lot of grey problem areas when they have this many miles. Well, I'm out of here till next Wed.

 

[Maniak]

Well....

I'm pulling the tranny... I checked the pressure at the pressure control port and the book says it should be 200psi or so... I got a high of 120.. low of 60... (with or without the external filter)

I then drove home (I was borrowing a gauge at a friends shop) and dropped the pan.. Even with my external filter installed I still had all kinds of metal in the pan.. looks like I may be losing the pump.. and of course the seals are toast..

Once we get it out I'll find out if I want to do the work (if I have the time) or if I'll let my friends shop do it.. (he used to work for aamco and he knows the a4ld too well).. Having the truck down for a while may not be an option.

~Mark

 

[SteveVB]

Mark,

I posted the ATSG manual info about BULK parts(Macko Distributing)

I would get a NEW pump not rebuilt. Also check the Boost pressure valve (bore 208) - like I posted before one of the tranny guys I talked to thinks it should be replaced during any rebuild.

I think most of the parts you can get from Macko- the prices are really good(compared to what I can do local) -

Good Luck