4 Speed issue

[Agent915]

Good morning,

I recently purchased a 1978 CJ5 , AMC 304 that the previous owner put a 4 speed in. When I shift into 3rd gear I get a rattling, clanking sound. It doesn't jump out of gear, just makes that noise. Any ideas? I have no idea which Transmission it is. I do know it has a granny 1st. Also, how difficult is it to convert from the manual clutch to a hydraulic?

Thanks

 

[Hedgehog]

With a compound first gear it is likely a T-18 , there are some other transmissions but this is likely to be the one and it is a VERY desirable choice. You can tell a lot by where reverse is in your Transmission . Right and down is the late jeep Transmission . In other positions it would be others like a Ford T-8 conversion. All are desirable.

These transmissions don't clank or rattle so it isn't likely to be the Transmission . I'd be looking at your Transmission mount, particularly the torque arm. If warn or tired or improperly installed it can bump and rattle as you describe. Also check your motor mounts, while less likely they can contribute to this sort of problem.

Then there is the possibility of having a bad universal joint. They will clank and rattle/ping.

 

[hagar]

Do you feel it in the stick shifter, the pedal, the floor, etc etc?

 

[Agent915]

With a compound first gear it is likely a T-18 , there are some other transmissions but this is likely to be the one and it is a VERY desirable choice. You can tell a lot by where reverse is in your Transmission . Right and down is the late jeep Transmission . In other positions it would be others like a Ford T-8 conversion. All are desirable.

These transmissions don't clank or rattle so it isn't likely to be the Transmission . I'd be looking at your Transmission mount, particularly the torque arm. If warn or tired or improperly installed it can bump and rattle as you describe. Also check your motor mounts, while less likely they can contribute to this sort of problem.

Then there is the possibility of having a bad universal joint. They will clank and rattle/ping.

Thanks HedgeHog!! Reverse is to the right and down. I will get under it this weekend to inspect everything. I had planned to do a bumper to bumper service anyway. What fluid would that gearbox take?

Danny

 

[Agent915]

Do you feel it in the stick shifter, the pedal, the floor, etc etc?

No, I haven't noticed any. Just the sound.

Danny

 

[mriplaybass]

T-18 uses 80/90W gear oil, if that is what you have.

 

[Hedgehog]

Never really considered that it might be out of oil.

 

[IOPort51]

rear axle?? shrapnel in it?? but only in 3rd gear??

 

[Agent915]

The Jeep pulls strong! There doesn't seem to be any issues at all as far as driving it. Just this annoying rattle, more of a "clanking" in third gear. It isn't terribly loud, just annoying and it worries me. The idea of a mount makes perfect since based on the sound. Got my fingers crossed!! Like I said, I'm crawling under it this weekend. I'll try to identify the Transmission , TC, and axles so I can be certain to get the proper supplies to service it. I am, (some say OCD) a stickler for vehicle maintenance and service records. I like things to be RIGHT. How do you guys feel about synthetics? I understand about frequent servicing be a waste of synthetics due to water exposure, but this will not be seeing water. Just back roads for fun and relaxation.

Danny

 

[gert]

look at your exhaust as well. the particular frequency of the motor being in that gear could cause it to rattle as well take pics we should be able to help tell you what you ha ve

 

[Hedgehog]

Gert hit what I was going to add right on the head. It could something as simple as the exhaust bumping a heat shield. Remember, each gear will set up its own resonance in the drive train. Try to evaluate the sound, tinny vs. heavy metal thumping.

I like the idea of synthetic oils and lubricants, but not in these older designed transmissions and transfer cases. The most significant advantage with synthetics are their tolerance to heat. While transmissions can get hot, they don't get engine temperature hot, so that is no real advantage. Synthetics are also very good at finding places to leak, a definite disadvantage for drive train components that were designed before synthetics were developed. My advice is to find the very best Dyno oil you can find. I live in a hot climate so I tend toward the heavier oils, but when my newly rebuilt T-18 /Dana 20 goes in they will get 80/90. Cold climates should use lighter oils for ease of starting in the winter months.

 

[Agent915]

With a compound first gear it is likely a T-18 , there are some other transmissions but this is likely to be the one and it is a VERY desirable choice. You can tell a lot by where reverse is in your Transmission . Right and down is the late jeep Transmission . In other positions it would be others like a Ford T-8 conversion. All are desirable.

These transmissions don't clank or rattle so it isn't likely to be the Transmission . I'd be looking at your Transmission mount, particularly the torque arm. If warn or tired or improperly installed it can bump and rattle as you describe. Also check your motor mounts, while less likely they can contribute to this sort of problem.

Then there is the possibility of having a bad universal joint. They will clank and rattle/ping.

UPDATE: Today I pulled the CJ into the garage and got it on stands. The plans were to do a more thorough inspection of the bottom side and to track down the source of that annoying "clanking" I mentioned in my original post. Good news on both! I found no rust, but more importantly, I think I located the source of the "clanking." I decided to drop the skid plate. When I did the Transmission mount came with it. The mount itself was broken in half and there was a bolt with a bushing, or at least what was at one time a bushing wobbling around in part of it. There were no bolts attaching the mount to the Transmission . I also noticed that the front driveshaft had been making contact with the starter housing. There was a slight scuffing on the shaft and you can see where it had rubbed against the starter. I checked the engine mounts and they seemed fine. Hopefully, this is the source of the clanking. I still need help id'ing my Transmission and Transfer Case . The Transmission is a 4 speed with a granny low. Reverse is to the right and down. There are 8 bolts on top of the tranny and "NP" right behind the shifter. I know the Transfer Case is a Dana, I just don't know if it's a 20 or a 300. I would like to service the entire drivetrain before I set back down, so any help on the id's would be greatly appreciated!
I want to thank everyone who responded to my original post, you were a tremendous help! I hope that I can return to the favor in the future. I love spinning wrenches and have had a blast tearing into my "new" CJ!

 

[gert]

NP stands for New Process that should then make it a NP 435 which is a very stout tranny advance adapters on sells a bell housing to adapt the Ford version of the NP435


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[Agent915]

NP stands for New Process that should then make it a NP 435 which is a very stout tranny advance adapters on sells a bell housing to adapt the Ford version of the NP435


Sent from my iPhone using Tapatalk

Thanks! I hope that replacing the mounts solves the problem! I tried to post some pictures of what I found but the page would "timeout" before they would load. Glad to hear I've got a stout tranny! Can I buy a complete mount kit or do I have to piece one together and will the Jeep mount work?

 

[Hedgehog]

Well, score one for me... Unfortunately I was wrong about the T-18 . I just went out to the garage and checked my T-18 . No, NP there so gert is most likely correct. Good Transmission , expensive conversion, very cool.

I bet when you tie the rear of the Transmission down properly the scuffing on the starter will go away. I am surprised that the mount was totally thrashed and a little clanking was the only issue. At least this is a relatively easy one to repair.

 

[gert]

Thanks! I hope that replacing the mounts solves the problem! I tried to post some pictures of what I found but the page would "timeout" before they would load. Glad to hear I've got a stout tranny! Can I buy a complete mount kit or do I have to piece one together and will the Jeep mount work?

I just looked up the Advance adapters kit and it looks like they are using the stock jeep Transmission mount, here is a link to Novak a good resource. Also the advance adapters was designed for the Dana 300
http://www.novak-adapt.com/knowledge/transmissions/manual/np435
http://www.novak-adapt.com/knowledge/transfer-cases/model-300
http://www.novak-adapt.com/knowledge/transfer-cases/model-20
Also a link to Morris 4x4 so you can see what the original mounts looked like to compare with yours. My jeep had a thick channel plate bolted in with the Transmission mount to act as a torque strap it would be a good thing to have to help the Transfer Case not wiggle around as much. http://search-parts.morris4x4center.com/search?ts=m&w=transmission mount&isort=score&method=and

It's easier for us to help you confirm what you have with pictures if you can post some up..... We like jeep pictures here

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[Agent915]

I just looked up the Advance adapters kit and it looks like they are using the stock jeep Transmission mount, here is a link to Novak a good resource. Also the advance adapters was designed for the Dana 300
The Novak Guide to the New Process 435 Transmission
The Novak Guide to the Dana Spicer Model 300 Transfer Case
The Novak Guide to the Dana Spicer Model 20 Transfer Case
Also a link to Morris 4x4 so you can see what the original mounts looked like to compare with yours. My jeep had a thick channel plate bolted in with the Transmission mount to act as a torque strap it would be a good thing to have to help the Transfer Case not wiggle around as much. transmission mount | Morris 4x4 Center

It's easier for us to help you confirm what you have with pictures if you can post some up..... We like jeep pictures here

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Good morning Gert,

Thanks for the links! I believe I have a Dana 20 Transfer Case after looking at the id information on the Novak site. I base this on the fact that just beneath the diamond where "Dana" is cast is the following numbers "C18-15-24-8" As far as pictures go.....I've tried multiple time to post some of the CJ, more importantly, the Transmission ,Transfer Case , and that fragged mount. They're stored in my Dropbox, so I didn't think it would be a problem to attach them. Wrong!

Danny

 

[shum8]

It's easier for us to help you confirm what you have with pictures if you can post some up..... We like jeep pictures here

What Gert said...... Now, if you are having issues uploading pics to your gallery here, try setting up a photobucket account and using that site to host the pics. Then all you have to do is copy the "img" link into your post here and the pic shows up. I use photobucket cause I'm lazy - been using photobucket for years and just haven't worked up the motivation to do anything differently.

R

 

[gert]

I use photobucket for that very reason just drop them in there and click on the link for the photo and paste in your post


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[Agent915]

Well, score one for me... Unfortunately I was wrong about the T-18 . I just went out to the garage and checked my T-18 . No, NP there so gert is most likely correct. Good Transmission , expensive conversion, very cool.

I bet when you tie the rear of the Transmission down properly the scuffing on the starter will go away. I am surprised that the mount was totally thrashed and a little clanking was the only issue. At least this is a relatively easy one to repair.

I certainly hope so! I was surprised when the plate came down that the mount came with it. My first thought was, "Hedgehog was right!" I was pleasantly surprised at how clean everything was. There didn't appear to be any leaks or other obvious issues underneath the Jeep. From what I gather from what you and others have said it seems that when the previous owner converted from a 3 to a 4 speed, he did it right. I'm really excited to get the mount replaced and everything serviced so I can get it down and REALLY drive it! That little AMC 304 is going to be fun! Thanks again for responding to my post and being a help!

Danny