Yes, it is time to "rebuild". But not the way you are thinking. You make no mention of noise, just no OD and the slipping so you blame the clutch inside the OD. Which "clutch" do you think is causing the slipping?

Since you are moving forward, the Sprague "clutch" (actually a bearing) is working in gears one through four. In OD, the OD does not stay engaged unless you take your foot off the gas. In the later, you should be glad the OD does not work because if it did, you would separate (break)the hub from the cone on the sliding member and have lotsa noise as you tried to get into OD. Repair would suddenly cost you another OD unit instead of under $40 plus about three hours of do it yourself time.

What is happening. For OD to occur, hydraulic pressure must hold the sliding member stationary against the brake ring of the OD. If pressure does not hold it there, the sun gear cannot drive the planetary gears so no OD occurs. In this instance, the sliding member is moving toward the brake ring but not being "locked" to the brake ring by high pressure. The sun gear starts to spin the planetary gears when no gas is applied, over running the one way Sprague bearing used in one through four, but the drag of the drive train causes a slip between the sliding member and the brake ring. When you reapply engine pressure, the sliding membe slips even more and the drive train finally "catches up" to the Sprague drive and you move forward as if the OD wasn't there at all.

All this because two $1.30 O-rings have worn out. Not an expensive repair except the OD has to come off the transmission to access these O-rings. Look in the FAQ's again at the exploded drawing of the OD. The part number 50 is what is causing your problem.

And the hardest part is taking the OD off the transmission. Once off, the two O-rings that are the major source of your problem are accessable using an 11mm wrench and about ten minutes tops.

One other potential source of the slipping. A broken pressure control valve spring. Rare occurence but it has happened. More common in the early 700's than the 200's.

Duane

P.S. To the list. I have been away for a few weeks. Hopefully nothing much that needed my attention was posted.

From what I've heard, and read in previous posts on this subject, you would probably be much better off looking for a used tranny that is in good shape. Cost probably somewhere in the $150 - $250 range... As an aside, I believe these transmissions (at least mine, anyway...) use type F ATF, could this possibly cause some problems?

Good luck,

Justin B.

We need "OD Guru" to chime in here, but here's some prelim info: those symptoms are not uncommon and are typical of failed seals on the actuating pistons. Yours sound like they are in a pretty advanced stage of failure. The hydraulic fluid gets past the seals and the little pump can't supply enough volume to compensate - thus, insufficient pressure to firmly engage the OD clutch. The problem initially surfaces as a lack of solid OD engagement at lower speeds, and/or when fully warmed up.

It's possible the IPD mini-rebuild kit could solve all your problems. It's also possible that a lot of mileage with a failing hydraulic system may have damaged the clutch. Disassembly is needed in either case, and with the unit apart for the seal kit you (or an OD-savvy mech.) can evaluate the clutch.

I've been running Redline MTL in both 240's for years. In the 83 it went a long way to curing a mild case of the same difficulties you have. In the 81 I view it as preventive maint. and it improved shifting smoothness in both cars. It's been called "transmission in a bottle" but can't work miracles.
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Bob (81-244GL B21F, 83-244DL B23F, 94-944 B230FD)