Why the gear grinding?

Why the gear grinding?


1965 CJ-5 w/ a 289 Ford Mustang V8 and Fo' on the Flo'
Hey guys. So idiot newbie question time. As I mentioned in my intro, just picked up a '65 CJ5 with a Ford 289 V8 stuffed under the hood. Now the transmission, I believe is the stock one, though I'm not sure, but it's a four speed with reverse in the first position, first in the bottom left, second in the top right, and third in the bottom right.

I have paperwork from the previous owner showing that the transmission was VERY recently rebuilt, and so I'm not sure if the issue in this case is with the operator, or the equipment. Hence, I divert my inquiry to the clever minds that frequent this place.

My issue is that almost every time I try to go into first gear from a complete stop, the gears produce a pretty nasty grinding sound and I kind of have to just slap the gear in there to stop it, otherwise I just end up taking off in second, which it seems to have no trouble with. Additionally, from time to time, it displays the same behavior when I shift in to reverse, but this is less common. So my question is, I know this transmission is not synchronized, but I've never driven an unsynchronized tranny, so am I doing something wrong here, or is there an issue with it that I'll need to address? If double clutching is required, I don't know how one could bring the engine revs any lower than they are to match the speed of first gear, but perhaps this is my ignorance as well...

I bow before your wisdom and thank anyone in advance for their help...


Thanks guys.
First ck your clutch free play.... if you have a manual they cover this pretty well.

When you push the clutch in there should be about 1" of pedal movement before you feel the throwout bearing and pressure plate.... you will feel a increase in resistance... The pedal movement from top of pedal spot to the feel of resistance should be about 1". It is adjusted with the linkage under the drivers feet on the bottom side of firewall & pedals.

Befor going into rev or granny 1st or unsyncroed 1st try one of the other gears...... This helps stop everthing and will go into those gears easier...

All you will find on the shelves of 20 stores is GL5 gear lube and its not the right stuff... YOu need GL4 Gear Lube for manual jeep trans and transfer case...... it will shift much better.... Better yet put the Amsoil MTF, Manual Trans Fluid, and it will shift even better . I put this in one vehicle 1.5 yrs ago and impressed me, solved sever issues and still issue less nearly 2 yrs later. Last night put MTF in my T18 trans with 36k orginal miles....... WOW WOW..... shifting like a nice transmission and NOT the long throw HD truck transmission it is....

My suggestion would be get yourself some some GL4 gear lube or better yet get 6 quarts of AMSOIL MTF and you will be a happy camper....

Here is on entry from a post started a few days ago

You ask a very good question........ I assure you the 70s FSM..... all of them say to use GL4 Gear Lube. I even went and researched and quoted every Jeep FSM, chapter, page, and verbage...... and they almost all said to use GL4 in the Jeep Trans and Transfer case. The exception would be the 1982 FSM and said GL5 and JEEP had a full line, accross the board, full recall of all trans fluids Oct. 1982 to replace the GL5 because so many transmissions were failing in all models.... it was a big mess.

There are a few.... very few.... GL5s that will work but not work as well as GL4.... they have different properties and are NOT interchangeable.

Originally Posted by Fjguercio

Here is a POST from me a few years ago.... I just copied and pasted here so hope nobody minds. YOU WILL FIND NOTHING BUT GL5 GEAR LUBE ON THE STORE SHELVES, NOTHING BUT.... The GL5 GEAR LUBE is the wrong fluid for old JEEP CJ Manual Transmissions and Transfer Cases, can also cause the SYNCROS to start rattle/noise and not work well or shift well. GL5 HAS THE WRONG.... LUBRICATION PROPERTIES.... AND.... IT IS CORROSIVE TO YELLOW METALS USED IN MANUAL TRANSMISSIONS. Some have posted, many posted, they could hardly shift after some time. Changed to GL4 and got better and quieter. I have done this dozens of times with great results.

So Please copy this to your hard drive and spread the word. This could stop a lot of JEEP MANUAL TRANS FROM FAILURE AND REBUILD BEFORE THEIR TIME. TRY IT YOU WILL SEE.................

The confusion with the AMSOIL product its rated as oil viscosity and not Gear Lube viscosity. The TWO OIL VISCOSITY SCALES cross or equal at these weights…..AMSOIL MTF is what I am going to change to since I do not WATER CROSS so the installed life will be of benefit. I currently have the Napa GL4 installed and very pleased with the correction of operation and is getting even better over time…. Almost no syncro rattle now

THE AMSOIL MARINE GEAR LUBE CAN ALSO BE USED FOR......... GL4 GEAR LUBE, it meets the GL4 spec, it can absorb more water before oil failure. SO... for those of you that play in the water alot that may be a good choice.

I have spoke to Amsoil Tech Support and the Gear Lube Engineer..... This is confusing to MARKET. Using Gear Lube Weight for gear lubes and OIL LUBE WEIGHT for the MTF product. They are changing their lit and web site to use Gear Lube Weight for MTF / GL4 Product. Should be done sometime next year. A Chem Eng In OIL here on JeepForum and I had a WEB Discussion on this in detail.... seems the Oil Weight and Gear Lube Weight cross here at these numbers. I’ts just confusing.

This info has been posted lots….. and many times on the forums. MOST of the Jeep Field Service Manuals say use GL4….. the only place Jeep messed it up was 1982 they said GL5 and had INDUSTRY RECALL ON ALL MODELS and changed the gear lubes and transmissions left and right…. Or very often.

The Amsoil White paper on gear lubes is a very good read.

The Novak Web site does have a little blurb on gear lubes/trans and its very confusing, not well written, and its leading many down the wrong path. I wish Novak would rewrite and update their info.

Gl4 and GL5 are not the same and not interchangeable…….. their applications are different…. Their properties are different….

It your syncors rattling. The gear lube on the shelves is GL5 and is a product made for the pumpkins of these big large towing capacity tow rigs. The GL5 has the wrong lubrication properties and is corrosive to the yellow metals in manual transmisisons. All the BorgWarner Transmissions in the older Jeeps should use Gear Lube.

The RIGHT GEAR LUBE is GL4...... GL4...... GL4.... Napa Sells it, call them and ask them to order you 1-2 gallons and its like $25 a gallon.... was $15/gal when I first started posting... not the price has almost doubled..... After 50 to 100 miles it will start shifting better and should start to get quite. My T18 did the same thing after I put the Gear Lube from the shelf.... it was GL5 and started shifting harder the the syncros starting rattle. Now almost silent and shift much better and its 32 years old.

Alternaitves Amsoil Syncromesh is a GL4 or Mobil 1 were both rated very high and and some of the least expensive on the list.

Bromgarrds Farm Stores, IA, NE, Co, Midwest area also have a GL4 gear lube. Sell 2.5 gal container for like $27.

I have posted this up many times, many folks amazed with results. Frankly I am SHOCKED another fluid bad for our Little Jeeps ALL OVER THE SHELVES. I HAVE LOOKED YOU WILL ONLY FIND GL5 ON THE SHELVES. Good for your pumkins but not for the trans/transfer. Also add a magnet to both drain plugs to catch the metal particle. I also took a "stick magnet" and rubbed the bottom of trans/trans and got more out that way.

SAE 85w90 Gear Oil GL4 (also meets GL3)
Part #SL24239
Mfg By Sta-Lube, sibisdary of CRC Industries
Bar Code 72213-24239
$25/gallon, phone order take 1-2 days to arrive, then pick it up, easy

I would also consider Amsoil MTF Syncromesh GL4 or the Mobil 1 Gear Lubes they were tops in performance and lower in cost that most. $8-10/quart.

Use GL5 Gear Lube in your Pumpkins and follow any recommendations for Limited slip or locker additives.

APPLICATIONS For GL4 and Amsoil MTF Gear Lube their GL4
Recommended for automotive and light-truck applications that require synchromesh transmission fluid. Applications include manual transmissions and transaxles such as New Venture NV T350, NV 1500, NV 2550, NV 3500, NV 3550, NV 5600, and Tremec T4, T5, T18, T56, T176, TKO500, TKO600, TR 3450 and TR 3550. Replaces MTF-94 fluid for Land Rover, MG, and Mini Cooper. Replaces Honda Genuine MTF fluid for manual transaxles and Texaco MTX fluid. Not for use in engines, hypoid rear axles, Limited-slip or wet clutch applications.

T5 .....Dexron III / Mercon, Mercon V use.....ATF.......
BUT....(except T5 from 1985 to 1991 use GL4 Gear Lube)
First ck your clutch free play.... if you have a manual they cover this pretty well.

When you push the clutch in there should be about 1" of pedal movement before you feel the throwout bearing and pressure plate.... you will feel a increase in resistance... The pedal movement from top of pedal spot to the feel of resistance should be about 1". It is adjusted with the linkage under the drivers feet on the bottom side of firewall & pedals.

Befor going into rev or granny 1st or unsyncroed 1st try one of the other gears...... This helps stop everthing and will go into those gears easier...

So what you're saying in the first part of your response is that my pedal for the clutch may simple be too loose? When I push the clutch pedal, there's a good few inches of swing before I feel it engage and resist. Could tightening this be a problem solver? And if so, why does it shift so smoothly into second and third?

I had considered the second part of your response, but even when, say I slow down to a stop for a light, push the clutch, and drop it straight out of second and into first, it often will still do the same thing. Should I remove it from second, put it back in, then try dropping it into first? This all seems a bit unnatural, but then, as I mentioned, I've never driven an unsynced tranny.

Could a change of gear oil really alter this issue? I had considered something like that, but didn't really think it was a possibility...

Thanks for your help so far! :chug:
FYI...Your 65 would have come with a T-90c I'm pretty sure and by the shift pattern you described sounds to be one.
Thanks Sasquach for the info, I appreciate it and I'm sure that will be a necessity to know in the future. I didn't get a chance to google it up and figure out which one it was, so thanks for saving me the effort!

MN CJ7, I think you're on it with the pedal adjustment, because on my way to my buddy's house this morning, the pedal went pretty much totally slack. In order to get it there, I had to really cram the shifter into gear, and it protested very audibly. Now it's pretty much totally loose.

Anyway, I crawled under there and found that the bolt connecting the linkage down there was completely loose, and the nut was GONE. So I was pretty much minutes from losing my clutch altogether, lol. Well, in any event, I fixed the problem for a grand total of 33 cents. MAN I love when problems can be solved that easily. It's a good day to have a CJ.

Thanks guys for your help! :chug:

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