T-18 question

[mwood65]

I have to pull out my transmission to change my throw out bearing (once it gets a little warmer) and am about 90% sure my input shaft bearing needs replacing also.....


Now if I am understanding what I have been reading and looking at once the retainer and snap ring is removed from the front the bearing can be punched out from rear and a new bearing installed without disassembling the entire transmission..correct?


Don't have the money to rebuild the whole trans and it shifts fine otherwise.


It might just be the throw out bearing that's bad anyways.

[tgreese]

For the T-18, you'll need a puller to disassemble the transmission. I would not try to take it apart with a hammer. I built a puller to take mine apart - seen here:

https://www.fsjnetwork.com/forum/viewtopic.php?t=10473

[Kaiserjeeps]

The mainshaft spins on needle bearings that roll inside the bore of the input gear correct? You remove the bearing retainer off the case freeing the input shaft and does not the input come out (with a little effort) along with the big caged ball bearing pressed on it and in the process drop all those needle bearings into the bottom of the transmission case? The needle bearings that always seems to send you on a mission to find all of them with a magnet or removing the shift tower to try and find them from the top? It's been a while since I have been inside a T-18.
Am I mistaken here?

Does the transmission make any noise? Excess growling or whining under load or coast?

[tgreese]

The mainshaft spins on needle bearings that roll inside the bore of the input gear correct? You remove the bearing retainer off the case freeing the input shaft and does not the input come out (with a little effort) along with the big caged ball bearing pressed on it and in the process drop all those needle bearings into the bottom of the transmission case?...

No. The bearing must be pulled from the input shaft and out of the case before the input shaft will come out. You cannot get the input shaft out of the case with the bearing installed. Same for the rear bearing. It's not like the Borg-Warner 3-speeds, where you can remove the input shaft and front bearing as a unit.

To assemble, you install the input shaft with the pocket bearing (rollers in the pocket) in place on the main shaft and drive the bearing onto the input shaft. See the thread I linked for the tool I made to install the bearing.

[Kaiserjeeps]

Yes I checked your link and read up. Good post. I was not sure about the T-18 verses the three speeds like you mention. That's why I threw some question marks in there. Thanks for the clarification as I needed it.

[tgreese]

Yes I checked your link and read up. Good post. I was not sure about the T-18 verses the three speeds like you mention. That's why I threw some question marks in there. Thanks for the clarification as I needed it.

Didn't mean to seem brusque. I've been through a few of the 3-speeds and thought the same before I started to work on a T-18. If there's a way to remove the main gear (input gear) without the puller, I don't know of it.

There's a Tremec T-18 book that covers these transmissions, and the step-wise descriptions are clear. Don't know if it can still be found ... the TSM is a good place to start.

[mwood65]

The mainshaft spins on needle bearings that roll inside the bore of the input gear correct? You remove the bearing retainer off the case freeing the input shaft and does not the input come out (with a little effort) along with the big caged ball bearing pressed on it and in the process drop all those needle bearings into the bottom of the transmission case? The needle bearings that always seems to send you on a mission to find all of them with a magnet or removing the shift tower to try and find them from the top? It's been a while since I have been inside a T-18.
Am I mistaken here?

Does the transmission make any noise? Excess growling or whining under load or coast?

Sorry I have been busy and forgot to reply to this thread.


The transmission does make noise.........


With engine running.........


In neutral with the clutch pedal out it growls....push it in and it stops. (throw-out bearing... right?)



Some noise going down the road in gear not much.
Probably normal for an old gearbox like that?
I guess it has a tad more noise when coasting than when under load.



Shifts good through all 4 gears + reverse

[tgreese]

In neutral with the clutch pedal out it growls....push it in and it stops. (throw-out bearing... right?)

Backwards for a throwout bearing (TOB). The fingers are away from the TOB when the pedal is up, and the TOB does not spin. If you have free play in the linkage when the pedal is released, the TOB does not spin and will not be noisy.

If it's noisy when the pedal is released and you have the proper free play in the pedal (ca 1" free play at the pedal), it has to be the input gear or the countershaft. The most likely culprits are the front main bearing or pocket bearing in the main drive gear.

Suggest you read the thread I posted above, where my T-18 had similar symptoms.

[mwood65]

Suggest you read the thread I posted above, where my T-18 had similar symptoms.

Ok, Read that other post (don't know how I missed the link before????)


Well, I will pull it apart this summer and if it's more than the input shaft bearing I guess I will probably have to look for a decent priced used one since I probably can't afford to build the whole trans.
or........spend the next 2 years buying parts...lol

[tgreese]

... Probably normal for an old gearbox like that? ...

Thought I'd mention - these truck 4-speeds make more noise (whine) than the Jeep 3-speeds or typical passenger car transmissions. They sound different with each gear, and quieter in top gear. Normal.

Don't decide to rebuild before you get the front main bearing out and look at it. Clean the bearing with some solvent, inspect and roll in your hands. If the race is rough or action is not mirror smooth, it will make noise. Look for looseness in the pocket bearing, and damaged rollers. If only the bearing is bad and the transmission seems fine otherwise, I'd suggest you install a new bearing and put it back together. These transmissions were designed for use in trucks like buses and dump trucks, and are strong and durable. Unlikely it needs everything unless it has a bazillion miles or was run with no oil or such.

[mwood65]

Thought I'd mention - these truck 4-speeds make more noise (whine) than the Jeep 3-speeds or typical passenger car transmissions. They sound different with each gear, and quieter in top gear. Normal.

Don't decide to rebuild before you get the front main bearing out and look at it. Clean the bearing with some solvent, inspect and roll in your hands. If the race is rough or action is not mirror smooth, it will make noise. Look for looseness in the pocket bearing, and damaged rollers. If only the bearing is bad and the transmission seems fine otherwise, I'd suggest you install a new bearing and put it back together. These transmissions were designed for use in trucks like buses and dump trucks, and are strong and durable. Unlikely it needs everything unless it has a bazillion miles or was run with no oil or such.

Thanks, yeah I have to have a throw out bearing and am hoping the input shaft bearing is all that is bad if anything.


Also I have another issue with that tranny you might be able to chirp in on, There seems to be no fill hole for the lube in it. I have cleaned it and inspected for the plug but where it's supposed to be there is nothing....well, sort of nothing.
There is a circle in the case like maybe a plug but is flush. I am used to seeing a plug with a protruding square piece for a wrench or Cresent wrench to fit on to -OR- a recessed square hole for a rachet to fit into.
So I have no way to check fluid level. Since I wasn't sure how much was in it I dumped a quart in through the shifter cover after I removed it.....That may have done more harm than good. I was thinking it would drain down into the case but I might just be a moron......


Well, I am a moron but I don't know if in this case (no pun intended) if it was a moronic move.

[rocklaurence]

First, the input needs to be pulled backwards to remove it from the case. If your going to replace the front bearing without total disassembly, you only need to be concerned about Not letting the needle bearings fall out during the process. If you can do it without lifting the input, your OK. Second, there should be a fill plug approx' in the middle of the case and a drain plug at the bottom.

[tgreese]

Thanks, yeah I have to have a throw out bearing and am hoping the input shaft bearing is all that is bad if anything.


Also I have another issue with that tranny you might be able to chirp in on, There seems to be no fill hole for the lube in it. I have cleaned it and inspected for the plug but where it's supposed to be there is nothing....well, sort of nothing.
There is a circle in the case like maybe a plug but is flush. I am used to seeing a plug with a protruding square piece for a wrench or Cresent wrench to fit on to -OR- a recessed square hole for a rachet to fit into.
So I have no way to check fluid level. Since I wasn't sure how much was in it I dumped a quart in through the shifter cover after I removed it.....That may have done more harm than good. I was thinking it would drain down into the case but I might just be a moron......


Well, I am a moron but I don't know if in this case (no pun intended) if it was a moronic move.

Adding oil from the top won't hurt anything. That's the easy way to fill it if you have the top off. You should be able to see the fill plug from the inside of the case above. As Rocklaurence says, there has to be both a drain and fill plug. I don't have a good picture. Predicted to be sunny tomorrow; I'll crawl under my truck and see if I can show you better where they are.

[mwood65]

Adding oil from the top won't hurt anything. That's the easy way to fill it if you have the top off. You should be able to see the fill plug from the inside of the case above. As Rocklaurence says, there has to be both a drain and fill plug. I don't have a good picture. Predicted to be sunny tomorrow; I'll crawl under my truck and see if I can show you better where they are.

I know what they look like and WHERE they are supposed to be from pictures but mine don't have one...


Unless it was the kind with a square sticking out for a wrench and it snapped off flush but I dont think that would be possible?

[tgreese]

Passenger side.