Overdrive help. popping out of gear and grinding.

I just installed a used Warn overdrive unit that i bought at Carlisle. and on the first test today In overdrive is working fine. But in direct it will move for a little bit and then on differnet torque load it pops out of gear and grinds. The guy i bought it from said it came out of a running jeep and worked fine. ( i trust him, because he is local to me and invited me to his house anytime to look at jeeps which i have done. and go trailriding with him. I dont think he would do this if he sold me a junk part) I have tried tightening the detent on the shifter and it worked better but still poped out of gear. I'm not sure if im missing a part like a syncro etc. Should i try tightening the detent more? I did see a video saying to measure the distance between the planatery gear and t-case. They said it should be 0.677 mine was 0.55. I dont know how crucial this is or what to do if its wrong. Would that make it grind?

A few thoughts 56, did you get the snap ring and spacer in and secure in the planetary gear set? If the snap ring is not seated it would allow the gear set to move and it would pop out of gear.

Next I would be sure the shifter is adjusted correctly. Be sure you are getting full engagement. Disconnect the shifter and fully engage the overdrive. Make sure the shifter will hook up without pulling it partially out of gear.

Typically clutch gears pop out under coast when the clutching teeth get worn. When they are extremely worn they will begin to pop out of gear under load as well as coast. These are the small "teeth" on the gear that the shift collar engages when you engage the overdrive.

There are two bronze synchronizer rings in there. If it is missing one you would have difficulty engaging/shifting the overdrive without grinding.

The detent pressure is correct when it gives you a solid engaging "click" and holds position over all types of bumps etc. It should be fairly tight.

If you take it apart take a bunch of pictures, especially of the clutching teeth and the inside of the clutch collar. Also take some pictures of the clutch fork pads.

Thanks Bmorgil.
I did put the spacer and snap ring in, to the best of my knowledge correctly. I didn't see any teeth worn or ground. I do think I am missing a syncro. I saw someone say it takes the same as the t 90 ? Is that true? I did try tightening the detent on the shiftier which made it better. Probably needs more adjustment. The distance from the transfer case to the gear was 0.55. Everything I find says it should be 0.677. Do you think that could be part of the problem? If so how can I change it?

I am not sure about the synchronizer being the same as the T90. It wouldn't surprise me, they look identical. The synchronizers go on each side of the clutch collar or "Sychro Block". You should have had one visible to you and in the sychro block when you installed the unit. The other one would have been inside the case. If the assembly is correct, the most common reason for them popping out of gear is wear. These overdrives are notorious for wearing quickly. If a lot of bad shifting was performed, the grinding will wear the teeth on the gear very quickly. The bearings in them run pretty fast and there size could be bigger. Dirty lube ruins them fast. Clearance in the shaft bearings will also cause shifting and gear engagement issues. Check the information you have that indicates "The distance from the transfer case to the gear was 0.55. Everything I find says it should be 0.677". I think that number is .667 to .680". You need to call Herm the Overdrive guy. The "stick out number" has varied based on when your unit was built and what ratio it is. If this is too short it will pop out of gear. If you are measuring to the top of the planetary bowl from the case and it is short (after you verify the correct number), make sure the rear 3 piece thrust bearing is present and in good shape and the beveled washer is in place and not worn out. You can shim the bowl gear out if Herm says to, he has the shims. I am assuming that is a T90 transmission. If it is a T14 there is a spacer on the output of the transmission that needs to be there. The T14 appeared in 1967. It will swap into your '56. If it is a T14 and that spacer is missing, you will be too short to the top of the planetary by about .125".

As easy as it is to pull it back out, you may want to take another look at it. Here are a few links if you don't already have them. Herm the Overdrive Guy is known throughout the Jeep community as the guy who specializes in these overdrives for repair and parts.

https://hermtheoverdriveguy.com/

http://www.ewillys.com/pdf/Warn-Over...ts-Catalog.pdf

Okay thanks. It is a t 90. Now looking at the diagram in that link I am missing the synchro. I'll be busy this week so I'll pull it apart and post some pics when I get a chance.

Hi folks, just wanted to update you. Its been a while. I did pull the overdrive out. I'll inspect and try to post pics tomorrow. For now i put the stock gear back In so I can still drive it.

Good idea 56, Take some close ups of the clutching teeth on the gear. Lets look at the condition of the clutching teeth after all that hopping in and out.

Overdrive pics.

More pics.

Heres the last of them. These two pics show the range of motion up and down on the bowl to planetary gears. Not sure if this is normal? Some of the gears look a little worn. I dont think to bad. But would like to know your thoughts. I know im missing the synchro an need a spacer on the gears. So maybe thats all that matters. Note there was no metal shavings in the oil. Just some dirt, dust etc. you can see in the pictures. Thats from being on my workbench. Ill clean everything before reassembly. It was just clean oily when pulled out.

I think it looks good 56. Some clean up as you said and reassembly with all the parts should do it. Some wear on the collar but no chipping.

The "stick out" everyone refers to, sets the total end play for the overdrive gearset. There needs to be some and not too much. Too much and it will pop out of gear. Too little and when it gets hot it will lock up. It doesn't need much, I don't know the spec, but I would guess it is somewhere around .010". You might be able to pull the PTO cover after install, and check the end play there.

Those were fantastic pictures - great job!

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Originally Posted by LarrBeard

Those were fantastic pictures - great job!

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Thank you sir! I lucked out with good lighting. Not really sure how/why but they did turn out good

Quote:

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Originally Posted by bmorgil

I think it looks good 56. Some clean up as you said and reassembly with all the parts should do it. Some wear on the collar but no chipping.

The "stick out" everyone refers to, sets the total end play for the overdrive gearset. There needs to be some and not too much. Too much and it will pop out of gear. Too little and when it gets hot it will lock up. It doesn't need much, I don't know the spec, but I would guess it is somewhere around .010". You might be able to pull the PTO cover after install, and check the end play there.

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I'll try to call Herm someday and get the correct specs and a synchro. Then see how it does.

You could even see the cat hair on them ;)

Okay, back to work on the overdrive. I had put the stock gear back in it before, so I was able to drive it. Then got busy and never worked on the overdrive since. But now that the body is getting closer to being done and I'll have Flossy on the road this summer, I really need to figure this od out. So I put the planetary gears in and there seems to be alot of forward-backard movement. I don't know if this is normal?

With it pushed in the spacing is 0.511
Pulled out is. 0.558.

Seems really far from the .677 it's supposed to be. I did get a synchro from KW, so all I need is confirmation on the spacing. I'd like to hear your thoughts then I'll try to call Herm on Monday.

Like we discussed back a few posts 56', I think that number range is .667 to .680. Give Herm a call to verify. This number sets the end play of the unit. It needs about .010". A better way than stick out would be to actually measure the end play on the assembled unit. I am not sure if you can do that through the P.T.O. cover or not. If you can, that is the way to set it. Herm should have spacers to set the end play or "stick out".

Alright, just got off the phone with Herm. So he said its likely the collar gears are worn and thats causing it to not work. I told him i was missing the synchro, and that really didnt concern him, like that was the problem. He said that if all else fails, since it worked in overdrive to just keep it in that gear for road driving. And i'd still have low enough gears for offroading. He said i can get arbor shims from Mcmaster-carr, or he'll send me some. And spacing it out might help.

It kind off depends on the kind of off road use. I have spent a lot of time on trails in 4-low with the overdrive engaged. The vehicle at the time was a CJ5 with the V6.