904 2nd to 3rd slip

[nigel]

Like the headline says it's slipping from 2nd to 3rd. I was out for a spin this weekend a d I noticed the slip was ever so slight at very high revs but if I'm very light on the throttle it just does not want to shift up. I tried shifting manually and it's also the same. The trans was slightly low on oil so I topped it up and it slightly improved the situation but after driving about 50miles of cruising at 80mph I noticed that it was back to slipping from 2nd to 3rd. When I stopped the car it was bleeding a lot from the bellhousing. I jacked up the car and the entire underside was coated with trans fluid. I checked the dipstick tube and that was fine.
Can anyone shine a bit of light on the subject? It's hard to believe a front seal just popped all of a sudden causing large amounts of oils to drain out. Also I'm running a 318 in the car. It's not like I'm out racing the car on the strip. It's just for cruising around to a few events

Any help is greatly appreciated

 

[beanhead]

I'm no expert trans guy but if it acts the same in 'D' and shifting manually, that should rule out the kickdown or shifter linkage..Sucks, but losing fluid like it is will cause slippage. Verify where the leak is coming from(they have a way of fooling you) and then you'll probably have to get in there for a look around..

 

[wyrmrider]

do adjust your linkage a little for later and firmer shifts once you locate that leak
when you rebuild use A999 parts- more clutches etc
I'd use ATF4+ even in a non OD non lock up unit- it's just flat better
Transgo reprogramming kit - after leak

 

[nigel]

So an update on the transmission. Adjusted the band's. It really improved the 1st to 2nd shift. 3rd was still no good. Well it was time to get down and dirty. Pulled the motor and trans out. Split the trans apart and found the rear clutch had two plates with very little friction material left. One plate was bare without any material and shinning. So the problem was found. Now to find the cause of the issue. Pump was fine. Converter was good. Valve body was in good order and clean. The clutch piston was the issue. It was hard and had a slight rip in the rubber.
I purchased a rebuild kit from a company in the states and upon receiving the kit I found the seals for the pistons were too small. Unfortunately I live so far across the pond I had to bring my clutch drum and piston to a company to have seals custom manufactured for the job. So the trans is back together now. Engine got a fresh coat of paint and changed all the frost plugs. The bay got a freshen up also. I'm starting to put the engine and trans back in tomorrow so fingers crossed this weekend she will hit the road without any issues and I finally get to check out my wilwood disc brake kit and see the improvement over drum brakes

 

[beanhead]

Glad you got it figured out, it's too bad it ended up causing so much hassle...and thanks for reporting back!

 

[nigel]

The reports are not over yet. It's rebuilt but the car doesn't move yet. Fingers crossed it will hit the road this weekend. Here's a picture of the guilty clutch plate

 

[dvw]

The rear clutch is applied in all forward gears. The forward clutch is the only component applied along with the rear clutch to provide 3rd gear. Take a good look at the reaction shaft support ring grooves, front clutch inner sealing surface that rides on those rings, inner and outer font clutch piston seals. Any of these would cause slow engagement of the forward clutch. The rear clutch would cause an issue with all forward gears. That being said you may have not noticed the slip in 1st or 2nd gear.
Doug

 

[nigel]

So an update on the car. Finally got the car out on the road late last night. It shifts from 1st to 2nd at around 20mph and to 3rd at 25mph. Looks like I will have to do some kickdown adjustment and take it out again. It was late last night so I did not get a chance to do so and due to ireland having the pleasure of a visit from the pope today I am a prisoner in my home and I cannot take the car out for a spin till tomorrow.
Also on another note the wilwood kit is awesome and it really feels weird driving the car with brakes.

 

[PP1RT]

So an update on the car. Finally got the car out on the road late last night. It shifts from 1st to 2nd at around 20mph and to 3rd at 25mph. Looks like I will have to do some kickdown adjustment and take it out again. It was late last night so I did not get a chance to do so and due to ireland having the pleasure of a visit from the pope today I am a prisoner in my home and I cannot take the car out for a spin till tomorrow.
Also on another note the wilwood kit is awesome and it really feels weird driving the car with brakes.

Doesn't the pope like Mopars or what??

 

[nigel]

Well his pope mobile is a dodge ram but for some strange reason they rolled up the streets of Dublin for the weekend. There is no way of moving a cat on the streets unless you are police, army or the pope so I will have to wait till tomorrow to get out for a spin again

 

[beanhead]

Ádh mór ort!

 

[nigel]

I need all the luck I can get. I'm driving across the UK with the car next week so hopefully I get all the bugs sorted out with it

 

[beanhead]

Do you have an auto association over there? (Something like our AAA) For a minimal membership fee they offer roadside help, towing, bring you gas, etc anywhere you are..invaluable on trips

 

[nigel]

When you get insurance over here it comes with all that sort of stuff so I'm well covered. I don't even want to think about having to call them especially after four years of trouble free driving followed by 5 weeks of hard work every single day day trying to rebuild the trans and fitting the new brake kit. Also painting the engine and engine bay. I didn't think I would have enough time to do all the jobs and still work a normal day but I'm getting close to the end of working on the car.

 

[wyrmrider]

does sound like a throttle pressure adjustment

 

[nigel]

Awesome. I researched the issue a lot and it's always great to get someone agree with me on the solution. Fingers crossed I can sort it tomorrow

 

[nigel]

So after a week of playing around with the car and adjusting the kickdown I think I've finally sorted it. The shifts are super smooth but at the correct speeds. I'd rather the shifts be a bit punchy but you can't always get what you want. I drove the car today and took it to 100mph with no issue cruising on the highway. Tomorrow I'm going to take it for a 250 mile trip to give it a good shakedown so it will either make or break the car.