4l60 / Transfer Case Grinding / Is this normal? (1 Viewer)

[Dubs2017]

I am getting close to wrapping up a vortec swap in my 62, and have noticed some odd behavior from my transfer case. Wondering if anyone has a recommendation, or experience with something similar.

Basically it seems like the 4l60 doesn't stop spinning enough for the transfer case to be shifted without grinding. With the engine off it shifts fine, but if in park or neutral it grinds going from 2H to 4L and back. It is also very hard to shift with the engine running. My transmission then grinds going back into park after shifting into 4L.

Has anyone else experienced this with the 4l60? Or any ideas on what could be causing this?

Here is a quick video to demonstrate.


Additionally, (and not sure if this could be related), I have a loud whine coming from the transfer case while driving (not while idling). I replaced the input gear with the long spline version when I did the rebuild, and have all new bearings. It is very similar to the noise in @TexFJ 's video in his post.

I'll be dropping the oil to check for metal and preparing to do another rebuild with maybe new gears, but if anyone has anything else to keep an eye out for i'd appreciate the tip.

Thanks.

 

[megolfer]

What RPM stall are you running?

 

[cruisermatt]

It’s an automatic. You need to be in park to shift the transfer.

 

[Dubs2017]

Thanks Matt. I was basing the transmission being in N on the glove box instructions (and habit). I have also tried in P, and it is EXTREMELY hard to get it into 4L. It will shift 2H to N easily in park, but takes a lot of pulling to get it to drop into 4L.

I chatted with @dbbowen about it and sounded like he has a similar experience with the 4l60.

 

[dbbowen]

Mine is the EXACT same way. For all of it. It was like that with my original 34mm t case. It was like that with the used 38mm tcase i got from @orangefj45 . It is like that with my brand new Toyota 38mm tcase i got. I too am using the long spline input gear, and its meshing with a brand new idler gear on all brand new parts.

On my case It seems like it likes to shift in and out of high and low the best when you are actively shifting between park and neutral as the rpms dip a little bit. In park its almost impossible to shift it. My idle speed is about 600 rpm

2wd/4wd is easier to shift than high to low (I installed a twin stick in hopes of making the shifting a little easier, its the same).

If you get stuck in neutral on the Tcase, it doesnt matter if youre in P, N, R, D, 3, 2, or 1. Youre F'd and need to turn your truck off to shift it out of neutral on the case.


It almost seems like the 4l60 output shaft just wont slow down enough for the split case to properly shift unless the truck is off, and its causing a bind inside the case. That split second between park and neutral or neutral and reverse frees the bind enough to let you shift.

The NV4500 transmissions ive installed with LS motors dont have this problem. It seems the output shaft on the manual doesnt keep spinning in neutral.


Im going to try connecting a ground to Pin 16 on the green pcm connector (or red if your pcm is older) and see if that helps at all. Thats the input for the 4low tune table in your computer. Theoretically your trans will shift differently when ground is applied to that pin, but i dont know if it drops the idle down lower to make shifting easier or anything. Outside of that im kind of at a loss with this one.


My tcase also has the high pitched whine at low rpm cruising. It did that with all 3 transfer cases i tried. Its got to be something with the tcase adapter. Its gear whine for sure. I thought the brand new case would stop it but it is exactly the same.


Ive triple checked my 4l60e output shaft that it was cut at the correct length and its within spec for the instructions. Im wondering if it maybe needs to be cut a little more? Maybe its too long, causing the spud shaft to deflect a little, which then misaligns the Tcase Input gear into the idler gear? I have no freaking clue on this one.

 

[Dubs2017]

Some progress on the whine, I think.

I dropped the oil (no metal), and took a look in the power take off cover. Nothing looks out of the ordinary to my eye, but curios if anyone sees anything I am overlooking.

Also, when I turn the rear output flange by hand with the transmission and t-case in neutral, there is what sounds like my whine coming from the front of the advanced adapter where is meets the 4l60. I loosened the speed sensor to see if that was rubbing by chance, and noise is still there.

Any ideas before I tear into it?

 

[cruisermatt]

Not sure what that is, I don’t think you need new gears though.

 

[Dubs2017]

Not sure what that is, I don’t think you need new gears though.

Thanks Matt. Appreciate the eyes on my gears.

 

[OSS]

If the rear of the vehicle is set up on stands so both rear wheels are off the ground, then engine is started with transmission in Park — and the rear wheels spin .... you’ve got your answer right there: transmission would be putting too much tension on the transfer input gears.

 

[adman02]

Something similar happened to me, too. In my case, the 2wd/4wd linkage arm on the transfer case was hitting the floor of the vehicle keeping the transfer case from fully engaging. At Matt's suggestion, I flipped the linkage arm over and the problem was fixed. Maybe that's happening to you too?

Here's a pic of the arm that I needed to flip...

 

[Dubs2017]

If the rear of the vehicle is set up on stands so both rear wheels are off the ground, then engine is started with transmission in Park — and the rear wheels spin .... you’ve got your answer right there: transmission would be putting too much tension on the transfer input gears.

That, is a great idea. I'll give that a try when I get the transfer case put back together and report back. Thanks for the suggestion.

Something similar happened to me, too. In my case, the 2wd/4wd linkage arm on the transfer case was hitting the floor of the vehicle keeping the transfer case from fully engaging. At Matt's suggestion, I flipped the linkage arm over and the problem was fixed. Maybe that's happening to you too?

Here's a pic of the arm that I needed to flip...

Good call, and thanks for the suggestion. I double checked that, and it's all clear and moving fine.

 

[dbbowen]

If the rear of the vehicle is set up on stands so both rear wheels are off the ground, then engine is started with transmission in Park — and the rear wheels spin .... you’ve got your answer right there: transmission would be putting too much tension on the transfer input gears.

This is interesting. Sometimes my truck pulls forward a few inches when i start it. Ive never tried jacking it up in park. I bet my wheels spin

 

[Dubs2017]

Thinking about next steps. Is there any good reason to not drop the entire T-case and adapter out by disconnecting the adapter from the "nosecone" at this spot and sliding the transfercase towards the rear until the spud shaft slides off the cut 4l60 output shaft? I might be overlooking something...

 

[cruisermatt]

Yes you can do that. I have a built a few transfer cases onto the adapter and shipped them as a assembly like that. You only have to slide it off about 1” of splines.
Make sure you support the transmission.
And remember the transfer case and adapter is about 100lbs together.

 

[dbbowen]

Man. I never thought of that. Ive had to rebuild mine under my truck so many times and this would have been so much easier. Im very interested in hearing what you find

 

[Dubs2017]

Yes you can do that. I have a built a few transfer cases onto the adapter and shipped them as a assembly like that. You only have to slide it off about 1” of splines.
Make sure you support the transmission.
And remember the transfer case and adapter is about 100lbs together.

Sweet. Thanks Matt. Gonna head down to ole harbor freight for a transmission jack/table thingy, I think.

Man. I never thought of that. Ive had to rebuild mine under my truck so many times and this would have been so much easier. Im very interested in hearing what you find

Coming up!

 

[Dubs2017]

Got the t-case removed and learned that the whine is definitely coming from the transmission. Output shaft seems very loose. The whine comes and goes if I just spin the shaft (transmission in neutral), but if I put any sheer pressure on the shaft while it is spinning the noise is very strong (pushing up on the shaft towards the floor while spinning it). Makes me wonder if the advanced adapter is slighting off and not centering the output and t-case input shafts.

How does this look to everyone? Should I yank the transmission out for a rebuild? (it also sounds similar to this video)

 

[dbbowen]

Got the t-case removed and learned that the whine is definitely coming from the transmission. Output shaft seems very loose. The whine comes and goes if I just spin the shaft (transmission in neutral), but if I put any sheer pressure on the shaft while it is spinning the noise is very strong (pushing up on the shaft towards the floor while spinning it). Makes me wonder if the advanced adapter is slighting off and not centering the output and t-case input shafts.

How does this look to everyone? Should I yank the transmission out for a rebuild? (it also sounds similar to this video)

Huh. My trans made that same noise when i spun it backwards in neutral while assembling my transfer case as well, but my output shaft wasnt loose like that. I bet you it is now though. It seems like the trans output shaft is not keeping the input gear on the Tcase perfectly still and maybe messing with the gear mesh on the idler gear? I swear to god mine sounds like its coming from the idler gear.

On the adapter really the only thing keeping the spud shaft in the right place is that big bearing on the adapter. Theres not really anything else supporting it. How did the Main seal on the tcase that rides behind the input gear look when you took it out? Any wear?

 

[Dubs2017]

Huh. My trans made that same noise when i spun it backwards in neutral while assembling my transfer case as well, but my output shaft wasnt loose like that. I bet you it is now though. It seems like the trans output shaft is not keeping the input gear on the Tcase perfectly still and maybe messing with the gear mesh on the idler gear? I swear to god mine sounds like its coming from the idler gear.

On the adapter really the only thing keeping the spud shaft in the right place is that big bearing on the adapter. Theres not really anything else supporting it. How did the Main seal on the tcase that rides behind the input gear look when you took it out? Any wear?

Good to know yours made the same noise. There is a transmission shop with a good reputation close by, so I might give them a call tomorrow to see about a rebuild. Would be great to baseline it and get some miles on the rig after more than a year in the garage. And I pulled the t-case off at the back of the adapter, so haven't taken a look at the main seal yet. Hopefully tomorrow if I can find some time.

 

[Snicklephritz87]

So question and a comment. I have had a 4l60e in my fj40 for 7 years. I cannot shift it while the engine is running. I actually haven’t tried to shift it in park. I will try it out this week. If it’s possible to shift in N i am all ears.

I would love to figure this out. I am half tempted to go back to a 5 speed.