The car in question is an 84 242 turbo with an M46 and 180K. I purchased the car within the last two weeks with out a working OD.

At the time I assumed that the problem was probably electrical, but after going over the relay, selanoid, and the 4th gear switch I found that all of the electrical components are ok. I then changed the fluid to Redline MTL and cleaned the lower filter under the OD inspection cover.

Currently the OD will engage at speeds above 60 mph and only upon removing my foot from the gas. As soon as the gas is reapplied the RPMs go back up into the range that they would be at w/out OD (about 3600 at 65 mph) If I apply the clutch and shift into od it does not seem to engage although the light is on.

Am I looking at a bad OD clutch? It seems that way since as soon as torque is applied the RPMs shoot up again, whereas if I don't apply gas the car will stay in overdrive.

How bad is it to rebuild an OD with the kit from IPD plus a new clutch? I printed out the instructions in the FAQ, but I'm a little unsure of myself.

Does anyone have an approximate price for this job if I took it to a shop to have it done?

Thanks

Greg Normington

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.
--
Bob (81-244GL B21F, 83-244DL B23F, 94-944 B230FD)

And I forgot, (age, long work situation away from home, and poor memory syndrom).

Check the fluid level in the tranny first. Old autos love to dribble fluids.

Carefull in removing the fill plug. I have heard they strip very easy.

Clarification, the clutches inside the OD usually are not able to be evaluated unless the cases of the OD are separated. I strongly do not recommend doing this unless there are external indicators (lotsa noise or no go in first four or reverse) of internal OD damage.

Synthetic fluids. ONLY if the are ATF Type F specific. Gear lubes and some tranny conditioners and oils may be too slippery for the OD to work properly.

Flame suit protection follows. ONLY if Type F Specific and in warm climates. Reason: For the Sprague bearing to drive in gears one to four, the rollers must contact the race DRY along the thin line of contact. All fluid must be squeezed out or they will slip. IF the synthetic fluid has improved cling and cannot be squeezed out from between surfaces, it will cause a problem. This same cling can also cause problems between the friction material and the brake ring in OD mode.

Synthetic fluid problems are more prevalent the colder the ambient temperature. One individual in Canada put synthetic gear lube in during January and went no where until he drained it and replaced it with plain old Type F a couple of times.

Duane

I'm in a similar position to you, but not quite so bad. I changed to synthetic gear oil and it has worked wonders, but I know it can only be temporary.
You can remove the OD without having to drop the whole box, so why not get a secondhand one and try it? Even if it is not perfect, you could live with it while at leasure you recondition your old one and then refit.