C6 Issues - Need Advice

[RDBillsJr]

Here's the vehicle: '87 F250 4WD, 6.9, C6, Gearvendor, 4.10 gears, almost 140,000 miles on the odometer, no history of repairs to the tranny. Tranny fluid looks normal, doesn't smell burnt.

Here's the issue: While going up a fairly steep, but short hill in town, in low gear, I only made it about halfway before I slowly came to a stop, engine turning about 1600-1800 rpm. GV was off. Had to back down and go around. Never had this problem on this hill before. The tranny seemed to shift normally on my alternate route home, shifted smoothly into each gear at about the right speed, although on the steeper parts of the hills I have to take, the tranny felt like it was slipping slightly (i.e., higher rpm than normal for the speed), but nothing drastic. Yesterday, on a milder hill about 1 block long on a residential street, I also had trouble getting to the top. Made it OK, but it seemed like it was slipping at slower speeds in low gear. (Again, nothing drastic, just seemed like higher rpm than usual for the speed, but I wondered if I was going to make it to the top.)

Before I take the truck in to the tranny shop and spend $$$ I don't have, does anyone have any ideas of what may be happening and whether there might be a fix that doesn't require a teardown (and can be done by a rank amateur shadetree mechanic with no auto tranny experience)??

Thanks,

Bob Bills

[mont91]

First thing has the tranny filter ever been changed. I doen't think this will help but it won't hurt, contrary to some other opinions. I am assuming the fluid level was correct. Have you checked the band adjustment. This is a simple procedure with two wrenches. There are two bolts with small heads and lock nuts on the drivers side of the tranny. One towards the front one in the middle. Loosen the lock nut and turn the bolt in gentely until it stops, count the turns for later info. Unscrew the bolts 2 to 2.5 turns and tighten the lock washers.All this is if I remember correctly. [img]/ubbthreads/images/graemlins/rolleyes.gif[/img]

[cdnsarguy]

Here is the book way.......

Raise or shinney under the blocked vehicle.
Clean all the dirt from the band adjusting screw, remove and discard the lock nut.
Install a new locknut, tighten the adjusting screw to 10 ftlbs torque.
Back off the adjusting screw exactly 1 1/2 turns.
Hold the adjusting screw from turning and tighten the locknut to 35-40 ftlbs.
Lower or shinney out from under truck, remove blocks.

EDIT.... One other point Bill, if the PNPS park nuetral position switch is not correctly aligned, it too can cause slipping in the gears.

Automatic Transmission Shift Rod or Shift Cable Adjustment... C6 and E4OD

1 Raise vehicle on jack stands or hoist. (I'd block well and scramble under)

2 From inside the vehicle, place the select lever in D/C6 and OD/E4OD . Hang a three

pound weight on the selector lever ( six pack still full)

3 Remove shift cable from the transmission lever ball stud/shift rod.

4 Pull down the lock tab on the shift cable body.

5 Position transmission lever in drive position. This is three detents from the front-most

lever position with the first position counting as one.

6 Connect the cable and end fitting to the transmission lever ball stud/shift rod.

7 Push up on the lock tab to lock the cable in the correctly adjusted position or tighten nut

and bolt.

8 Remove jack stands and lower vehicle from hoist. Remove three pound weight from

column shift select lever.

9 After making adjustment, check for Park engagment. Check the transmission control lever

in all detent positions with the engine running to make sure correct detent/transmission

actions, readjust if necessary. Reset the PRNDL indicator as required.

CAUTION:
Under no circumstances will it be permissible to adjust the cable/shift rod in any position

other than D for C6 or OD for E4OD.

Now all should be ok if it is in PARK and everything works, remove blocks.

Road test...................(drink warm beer)