Conditions for A4LD lockup?

[you there]

Anyone happen to know the parameters that need to be met for lock up in an '88 model? I can not get lockup under 50mph in my Ranger. It is shifting into OD as a manual downshift into Drive (and subsequent shift) has verified this. Little info on the truck: 88 Ranger, A4LD, 2.9, virtually all stock, factory 3.73s and 31s. Don't know any history of the vehicle at all since it's a fairly new purchase. Bought it as a problem vehicle and trying to get all the bugs worked out. New Motorcraft IAC and TPS.

 

[kimcrwbr1]

Not sure but the throttle position senser and the map and maybe engine rpms. On later models with the VSS if yours has one? The experts here will know better
Is yours not locking up?

 

[kimcrwbr1]

Have you clocked your speedo 3.73 would be the ratio for stock 15 inch tires with the taller tires maybe you putting your foot into it more. Maybe a 410 carrier in the rear will allow you to let up on the foot feed.

 

[kimcrwbr1]

My 83 came stock with 14 inch wheels I put the 15s from a B-II and 3.73 carrier and works great. I have the 21575R15 tires with the 3.72 diff. The 4.10 will give you more pulling torque and make it a LS carrier.

 

[you there]

LSD is separate from the 4.10s. The '87 in my sig is factory 4.10s with an open differential (could be wrong though as I haven't looked since I bought it some time ago).

The speedometer is definitely off (31x10.5 vs 215/75 factory size) but before I go buying/swapping speedometer gears I want to make sure that all variables are accounted for beforehand. It is locking up but only at 50mph+.

So far the only wild card I can think of is the ECT. I'm not seeing any codes that could be related to it but the engine is running a bit cool I think, possibly skewing things a bit? Temp gauge doesn't get half way up, probably around the "A" in "NORMAL."

 

[4.0B2]

the speedo gears are only like $7 at ford.... I have a few of the stock ones that I no longer need, If you tell me what tooth count you need, I'll check my stash.. you can have them for the price of postage.

 

[kimcrwbr1]

Is that 50mph according to your GPS? The thing is if it locks up at lower speeds you will need to push harder on the foot feed to maintain speed therefor reducing fuel mileage. Like pulling a mountain pass it will give you better performance to shift into 3rd and run higher rpms pulling a long hill. The 2.9 is no power plant thats for sure.

 

[you there]

Yeah, I should have been more clear about that; 50mph indicated on the speedometer. I'm not concerned about power/fuel consumption yet. Right now I need to figure out why the torque converter only locks up at 50mph (again, speedometer indicated) or higher.

4.0B2, 'preciate the offer. May take you up on that.

Edit: IIRC, 50mph indicated was somewhere around 60 actual speed.

 

[fightin irish]

I too have a trans issue does not feel like it is going into o/d at 55mph the tach is reading 2500 rpms down shift to drive and no change in rpms.
3.73 gear
235/75/15 any ideas?

 

[adsm08]

I am pretty sure no converter lock-up on the A4LD below 50 is normal operation.

It's not like newer electronic ones that modulate it and lock it up in lower gears or at lower speeds. It's just there for the highway.

 

[you there]

Seems to be the case. It just feels weird........

Anyway, thanks for the input!