How much grinding is ok when coming out of overdrive?

I've got a '57 CJ5 with F-134/T-90/T-18 and an overdrive of unknown origin. The OD looks brand new and both the trans and t-case were looked at about 10 years (but only 300 miles) ago. Not sure what, if anything was done except a new pan on the t-18. The t-90 shifts great.

Everything works as it should with no unpleasant noises until I try to shift out of overdrive. Most of the time it shifts out seamlessly, but about 30% of the time it will grind pretty badly. I never force it, and can usually stop the grinding by shifting into neutral before trying to get out of OD again, but not all the time. There have been a couple of occasions when I've had to come to a complete stop before it would shift out.

This does not seem normal.

Both the trans and t-case are full of 85-90.

Are there any adjustments I can make to eliminate this periodic problem? Should I pull the OD and, if so, what should I look for and is there a good how-to available? This would be my first time really digging into this truck.

Thanks!

 

Assuming this is a Saturn/Warn OD, they should not grind shifting either up or down if the blocking ring is doing its job. That said, a lot of the do grind a bit but yours would appear to be on the excessive side. You can pull the back portion of the housing to check the ring.
Some general info from 2A Page
http://www.cj-2a.com/_Media/warn_od-1963.pdf

 

Thanks for the reply, Duffer.

Does "blocking ring" go by another name in the documentation you linked? Can't see it anywhere.

 

Synchro-Block ring.

 

I have found that my OD does this after sitting for extended periods of time. I did find that when I shift if I let the engine RPM's come down between shifting it works much better.

 

Thanks for the translation, Walt. I have plenty of experience spinning wrenches on motors and chassis components, but know nothing about transmissions or transfer cases.

The blocking ring does not look very easy to access in the link duffer provided. Do I just pull the cone-shaped part of the housing off? If so, should I just check the gears I can see for wear/damage? Any detail y'all could provide in terms of what I should look for would be most appreciated. I don't mind jumping in over my head so long as I have a reasonable expectation of not making the problem worse. Right now I get the feeling I would have no idea what to look for and might really make a mess of things.

I'll keep searching the archives as well.

Thanks,
Mike

 

Thanks for a great file to add to the collection!!

 

General questions aren't very useful, so I kept reading and have a couple of more specific ones:

1) Does the oil collector for the OD require the OD to be engaged to work? I only use my OD rarely, so if it needs to be engaged before it will get oil then it probably isn't getting much, which may account for the grinding.

2) If I pull the rear cover off of my OD will a bunch of parts fall out all over my driveway, or will things stay put so I can take a gander at how this thing is put together?

Thanks!

 

#1....no the oil gets caught in the tube weather it's engaged or not so it gets oil all the time.
#2...not sure i never pulled one apart but someone else would chime in

 

Drop a note to Herm at www.hermtheoverdriveguy.com. He is usually very helpful, and is very knowledgeable about the workings of the overdrives used in combination with the D18 transfercases.

 

Like oddfirejeeper said, as long as the output shaft of the transmission is turning, the oil collector is in place, and the transfercase oil level is sufficient (full) the overdrive gets oil directed to it.


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Make sure that the clutch isn't dragging. You might try changing your gear oil before tearing into things. If you are using a GL-5 lube, you might try going to a GL-4 lube. I read on a gear oil web site that some transmissions don't like GL-5 lubes because many are formulated with friction modifiers for limited slips which can make them too slippery for synchronizers to work. Synchro blocking rings require a certain amount of friction to work efficiently. Also many GL-5's have an active sulfate which can eat away at yellow metals such as synchro blocking rings.

 

Before trying to remove a Warn overdrive, go to Herms site and read the directions on how to do it properly. If you run into a snag, give him a call and ask what to do. He is very helpful. If unsure about the condition of your overdrive, you can send it to Herm in a USPS medium box for 12 bucks. His turn-around is pretty quick and the average rebuild is fairly inexpensive. I have had him rebuild several of them and they usually are less then $250 for a rebuild.

 

Thanks very much, everyone, for the advice. I'll change the fluid to GL-4 and check the old stuff for particulates. If the problem recurs I'll study up on Herm's site and let you know what I find.

I promised pics of my Jeep a long time ago. Better get on that before asking another question.

Cheers.

 

Any luck with the oil change?

 

Thanks for the follow up, 80cj. Sadly I haven't had time to do it yet.

My wife and daughter are leaving town for 4 days starting this Saturday. (4 days alone in my own house! Unprecedented!) Should have time to do it then, and will report the results back to the forum ASAP.

 

Just curious. Enjoy your 4 days of freedom!