Help with a slipping clutch after transmission change.

This will be my first post, I've learned a lot looking at this forum, but this is the first time I've needed help from here (luckily).

I changed out my transmission fluid to Redline MT-90 yesterday which seems like it should be good for it based on what I've read. The truck has 106,000 on it and I don't think it's been changed recently (or ever), it was looking really thick.

Everything went well except one I got on the higway and it warmed up, I noticed consistent slipping when engaging the clutch in 4th and 5th gear. The rpms rise for a few seconds as high as 4k sometimes, then fall back like they should. It also seems to be exclusively in 4th and 5th, 3rd and below are totally fine.

The fluid level is good, so I'm guessing the clutch has a problem (worn out) that's just now showing up with the new oil.

Does anyone have any idea if that's where I should start looking for issues, or if this is more likely in the tranny itself? Will it possibly work out over time? And am I hurting it driving it daily or should I get it asap?

Thanks for any advice anyone can give, and I sure hope I don't need a new clutch already at 106k.

 

Your symptoms sound exactly like a clutch going out normally. Slip in the higher gears but not the lower. You can verify by putting the truck in a higher gear and flooring it, if the RPMs rise like that it definitely sounds like your clutch is on its way out. The fluid change is a good thing but shouldn't have anything to do with the clutch slipping.

 

Wow, that was fast, thank you man.

That's what I was afraid of, sounds like I need to start looking at clutch prices

Just to eliminate any other sources, I also changed the spark plugs and cleaned the throttle body at the same time. Do you think theres any way either of those could be causing the problem?

 

only way for RPMS to raise like that on a manual truck without your foot on the clutch is for the clutch to slip.

 

Haha well I guess that about settles it. Whats a good replacement clutch for. the four cylinder? I off road a fair bit, rarely tow anything but I would like to get something above factory specs.

 

Did you bleed the clutch after install?

Does your pedal have a little travel, before the pedal engages the push-rod for the clutch master cylinder, under the pedal?

 

Wonder if the rear seal on the tranny is leaking? Clutch condition will foretell that- wouldn't hurt to replace while you are in there!

 

There is a bit of travel under the pedal before it engages, maybe an inch or a little less.
To be clear I haven't changed the clutch or done anything to it since I got the truck ~10k ago. This is the first fluid change I've done besides oil changes.
I didn't bleed the clutch since I only changed the transmission and transfer case fluids (both differentials as well). Should I have?

I don't see any obvious leaks on the rear of the tranny, is that something that would show on the outside of it?
I'm also wondering it could just be the master/slave cylinders since the clutch feels fine otherwise.

 

Since you have some play going on, to eliminate the possibility of air in the clutch line, I would bleed it. The other issue may be the clutch throw out bearing, but you will have to look inside the housing to determine the condition of it.

When you replace the clutch, you will either see oil in the housing or not - my seal leaked with very little outside indication- and just a little oil got onto the clutch, making it slip. I don't know if the rear seal can be pulled from the outside of the [edit: engine] on your model (my 85 PU could). If so on yours, I'd consider replacing it while you are replacing the clutch if you can.

 

I'll definitely bleed the clutch tomorrow and see what happens.

I guess now I'm wondering how crazy it is to change the clutch on my own and save on labor. I've never attempted anything nearly that involved but I've read a few threads on it and it doesn't seem too bad.
Have any thoughts on attempting a switch alone the for the first time, or what could go majorly wring if I screw up?

 

I haven't done my trucks alone either but watched and helped with mine. It isn't that hard if you have the lift, time and tools for it. I wouldn't do it if its your daily commute car and you don't have a weekend free for it. I did my own on a BMW and that took all weekend because all I had was jack stands and my arms kept cramping up because I was laying on pavement under a short car- the truck should be much easier due to the ground clearance!

 

The rear transmission seal is not going to get on the clutch disk as the clutch is between the engine and transmission inside of the bell housing. The rear transmission seal is on the opposite end where the drive shaft goes into the transmission.

I think you are meaning the rear main seal for the engine crankshaft, leaking motor oil. Is that correct?

 

If the clutch is slipping and he has play in the clutch pedal , he needs a clutch or the rear main engine oil seal is leaking all over the flywheel causing the clutch to slip .
The clutch in his truck is hydraulicaly assisted by means of a slave cylinder and master cylinder .
The slave and master cylinder are responsible for clutch release and clutch apply . The slave and master have nothing to do with clamping force
Guys on this forum seem to like clutches from Marlin Crawler
https://www.marlincrawler.com/


https://www.tacomaworld.com/threads...on-your-5-speed-transmission-write-up.338836/

 

My apologies. Jumped into the discussion before reading everything. That amount of pedal play, is within normal range. If/when you change the clutch, take note of that play, and that there still is a little or similar amount. Somewhere between 10-15 mm travel is Toyota spec. Verification is needed on that to be more accurate.

 

Doh! You are right sorry for the mistake- late night + all day on the road... I had an old 1968 BMW that had the opposite provlem, the clutch had tranny oil oil on it and it was the forward seal of the tranny leaking on it.

 

Thanks for the replies everyone.

It looks like Marlin Crawler only makes clutche's up to 2004, is that correct or am I just not in the right place on their site?

After hearing about the rear main engine seal I'm now guessing that could be the issue, as I recently switched the engine oil over to synthetic which could be seeping through to the clutch. If that is what's happening, im guessing i need to switch it out ASAP, should I assume my flywheel will be shot too or can I possiby salvage that?

I have plenty of time and tools, but nowhere good to do the work. I moved to Nevada a few months ago and unfortunately don't know anyone with a garage and can't do it at my apartment

 

So it sounds like it could possibly be coming from either side/seal? Since the problem showed up right after I switched the tranny to synthetic I'm leaning toward the tranny seal instead of the rear engine seal. Does anyone have any idea how common a tranny leak is vs an engine seal leak?

 

You would see oil dripping out of the bell housing if it were bad enough to cause the clutch to slip. My rear main leaked for a long time before it caused the clutch to slip, and it leaked to the point where it was trailing back underneath the truck even before the clutch started slipping.

I would bet it is an adjustment issue, or a worn clutch.

 

My clutch would slip until I adjusted my clutch pedal. 1 inch of play seems to much. ( screw that is out of focus )

 

Cool, I did see what looks like a bit of seepage where the rear driveshaft meets the tcase/tranny, but I need to look more closely to be sure.

I'll definitely be checking out the clutch adjustment after work too. Is that something I can just slowly fiddle with until it stops slipping or do I need to be more careful? I'm guessing from the picturest that I should be decreasing the gap length by bringing the screw downward, or do I have that backwards?