Need a Little Help on T-5 Transmission

After three years of working on my scrambler I have hit a hurdle. I purchased a running T-5 transmission 3 years ago and installed into my project, Until this past weekend other then installing I had not touch the transmission. Well my hurdle is that I filled the fluid, yes she sat empty for three years in the garage and I installed the shifter and now she will not shift without a lot of force. DO you all think that because she sat so long empty that caused my problem. I can get her into gear but it takes a lot of pressure. At first no movement at all, then 3-4 gear now it seems that I can get 1-2 no 5 or reverse yet. Should I pull her back out and open her up or do you think over time the shifter will loosen up from now having fluid?

Any suggestions.

Well, I ordered a rebuild kit and will remove and try again. Maybe I can get this done in a timely manner this time.

I had a similar issue recently with a T-176. I had replaced the top cover, that contains all the shifting parts. Well, I cleaned it so good, there was no oil left on it. When I first started the Scrambler, it would not shift, But, after about a minute, enough oil splashed up to the top to lube everything, and it shifted fine

On yours, sounds like something inside is not right, it should have started shifting by now

I found my T-4 to be VERY sensitive to using the correct oil and having that oil a the correct temperature. If I crank up and run out on a cold day (which is almost never here in Louisiana), it shifts like junk. After 20 minutes or so, it's shifting fine again.

What oil did you use?

DirtyB said:

I found my T-4 to be VERY sensitive to using the correct oil and having that oil a the correct temperature. If I crank up and run out on a cold day (which is almost never here in Louisiana), it shifts like junk. After 20 minutes or so, it's shifting fine again.

What oil did you use?

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Dirty,

What oil do you use?

DirtyB said:

I found my T-4 to be VERY sensitive to using the correct oil and having that oil a the correct temperature. If I crank up and run out on a cold day (which is almost never here in Louisiana), it shifts like junk. After 20 minutes or so, it's shifting fine again.

What oil did you use?

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I used Pennzoil Synchromesh Manual Transmission Fluid.

PENNZOIL SYNCHROMESH MANUAL TRANSMISSION FLUID:
•Exhibits excellent low-temperature performance
•Meets GM Specification 9985648 and Chrysler Specification MS-9224
•Suitable for use in GM manual transaxles and transmissions requiring GM Part No. 12345349 or 12345577
•Suitable for use in Chrysler transaxles and transmissions requiring Part No. 4874464
•Excellent synchronizer performance
•Excellent yellow metal compatibility

I tried a bunch of different fluids in the T5's:

automatic transmission fluid
Syncromesh
Mopar MTF for the 6 speeds
Royal Purple MTF
30 weight motor oil
80-90 weigh gear oil

The thinner stuff always made the shifts feel a little "notchy". I believe this is because thinner fluids do not slow down the blocking rings in the syncro assemblies fast enough, so when you go to shift, everything isn't quite lined up. If you shift slow, no problems.

The thicker fluid, like 90 weight gear oil, works better IMO. No "notchy" shifts. If it is extremely cold, it will take a few minutes for gear oil to thin out, but no big deal. The transmission still works/shifts fine, just feels "sluggish".

I sent some factory Jeep T5 fluid to a lab, it is basically 90 weight gear oil.

I run NAPA 80-90 weight gear oil in my green Scrambler's T5, no problems. The NAPA gear oil is "yellow metal safe", which is important.

In the end, all T5's will die a horrible death

I believe I used the 90W gear oil. What Spank says is true, thinner lubricants tend to mess with the synchronization (at least I think that's what was happening). A mechanic friend of mine told me that these units were very sensitive to that just by the nature of their design. He had me drain the transmission overnight to get as much of the old oil out as possible. After I replaced with the 90W (I don't know what came out), it did seem to shift better. If you search the web, there's hundreds of posts asking this question about which oil to use.

I have heard over and over that the T-4/5 really were under designed for the drive train of the Jeep. I have an AX-15 that I plan to put in when I have the time....

On another note, is your clutch linkage properly adjusted? It may be that the pedal is going to the floor, but in reality, you aren't pushing the clutch in all the way!

I'd always planned on eventually swapping in Redline MT90 into my T5, then I got a T176 for a spare and figured I'd just run the T5 till it dies, then swap in the T176.

Still thinking about running MT90 in the T176 though. Anyone here running it?

wm69 said:

I'd always planned on eventually swapping in Redline MT90 into my T5, then I got a T176 for a spare and figured I'd just run the T5 till it dies, then swap in the T176.

Still thinking about running MT90 in the T176 though. Anyone here running it?

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The T176 is more closely related to the older, big, 1-ton truck 4 speeds. I always ran 80-90 weight "yellow metal safe" gear oil in mine, no problems.

That newer "MT fluid" stuff is for newer style transmissions, I would not run that in a T176

spankrjs said:

The T176 is more closely related to the older, big, 1-ton truck 4 speeds. I always ran 80-90 weight "yellow metal safe" gear oil in mine, no problems.

That newer "MT fluid" stuff is for newer style transmissions, I would not run that in a T176

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I always assumed the MT was "manual transmission" and the 90 was the weight. Figured MT90 was just synthetic 90W gear oil. Is that not the case?

wm69 said:

I always assumed the MT was "manual transmission" and the 90 was the weight. Figured MT90 was just synthetic 90W gear oil. Is that not the case?

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Its not the same as older 90 weight gear oil, I looked into it

From Red Lines site:

75W90 GL-4 gear oil (similar to SAE 5W40/10W40 engine oil viscosity)
Popular in Nissan, Mazda, Mitsubishi, VW/Audi, Lotus Elise/Exige, Toyota
Offers quicker shifts, perfect synchronizer coefficient of friction
Safe for brass synchros, as it lacks the reactive sulfurs found in most GL-5 oils that cause damage
High performance gear protection and longer synchro life
Eliminates notchy shifting, even when cold
Satisfies the gear oil viscosity requirements of 75W, 80W and motor oil viscosities of SAE 40, 10W40, and 15W40
Recommended for GL-1, GL-3, and GL-4 applications, as well as where most special synchromesh fluids are specified

It's thinner then the 80-90 weight, better suited to transmissions that need "syncromesh" type fluids. I would save my money

Good to know. Thanks!

Well after letting the transmission sit with new fluid in her she has been loosening up, now able to shift all gears but 1st but each and every week it get better.