Hard shifting aut box

[Fischer]

Hi

First please excuse my english.... Should have plaid more attention in School ....

Can anyone explain why my aut gearbox shifts hard, both up and Down, at low speed, but if i accelerate medium hard it shifts ok ....?

Would an oil /filter change Make any difference..... .?

/Fischer
Denmark

 

[rockdemon]

might be play in the drive train rather than the box - see what harvey suggests

 

[harveyp6]

It's difficult to know from your description, but as a first stage I'd suggest making sure the fluid level is correct, looking for excess play in the drivetrain as suggested above, and if that's all OK, roadtest and check the shift speeds and the engagement of "D" & "R" from NEUTRAL to give an idea of whether the kickdown cable is adjusted correctly.

 

[Fischer]

Hi again

thank very much for reply's .. being a "Rover rookie" I have few more questions, sorry :roll:

What should I look out during engagement of "D" & "R" :?:

Does anyone have a list over the correct shift speeds :?:

Best regards
Fischer

 

[harveyp6]

What should I look out during engagement of "D" & "R" :?:

Harsh engagement, clonks etc. If you have that it could be play in the drivetrain, if so try with the handbrake on and with it off. If it improves with the handbrake on then the play is in the driveshafts or rear hubs, if it doesn't it's in the propshaft or diff. It can also be the idle speed too high, or the gearbox pressures too high. Look for any delay with the engagement as well.

Does anyone have a list over the correct shift speeds :?:

They are all listed in the Workshop Manual, but as a guide you should not have a harsh engagement, or a clonk on the 2-1 downshift on a closed throttle, because that indicates the pressures are too high, which will be confirmed a lot of the time by having to lift off the throttle to prompt the upshifts. Too low pressures make it change up too early.

On a very light throttle in "D" it should change into SECOND by about 10mph, and into TOP by just over 20mph. Full throttle and kickdown change speeds are obviously a lot higher, but the book readings have to be used as a guide taking into account that most engines now aren't at the peak of performance that they were when they left the factory.

 

[Fischer]

Hi again

Damn Harvey, you know everything ....

Rpm is about 1100 in neutral when hot .... That is a bit on High side ... or ?

When the gearbox is hot it clonks when i approach crossings etc on closed throttel and i also have to lift the foot to make it shift up at low speeds... So i assume the the pressure in the gearbox i to high.. ... Is that something i can i fix myselfs ?

Fischer ...

 

[harveyp6]

Rpm is about 1100 in neutral when hot .... That is a bit on High side ... or ?

That is too high, try to get it down to 700-750, but use a proper tachometer, the one in the car isn't accurate enough.

When the gearbox is hot it clonks when i approach crossings etc on closed throttel and i also have to lift the foot to make it shift up at low speeds... So i assume the the pressure in the gearbox i to high.. ... Is that something i can i fix myselfs ?

I'd agree that the pressures sound too high. Set the idle speed, and then you can try adjusting the kickdown cable to reduce the pressures. The outer cable adjuster needs to be wound upwards into the bracket to do this. Make a note of the starting point and adjust it a turn at a time with roadtests in between adjustments until you get a position you're happy with.

 

[Fischer]

Hi again

Got the idle down to 750-800 rpm..... And the engine still runs ok.... So i think i leave there :!:

I haven't tried to adjust the gearbox yet .... But i now know that my car a type 303 gearbox .... Don't know if its good or bad .... i am having some trouble founding out how adjust the cable.... The haynes manual dosen't make much easyer..... :roll:

/Fischer
Denmark

 

[harveyp6]

Hi again
Got the idle down to 750-800 rpm..... And the engine still runs ok.... So i think i leave there :!:

That's better and should make a noticeable improvement.

I haven't tried to adjust the gearbox yet .... But i now know that my car a type 303 gearbox .... Don't know if its good or bad ....

The 303 was the latest and best incarnation of the BW35 in the Rover. Unfortunately after 40+ years there's no guarantee that the internals will match the dataplate.

i am having some trouble founding out how adjust the cable.... The haynes manual dosen't make much easyer..... :roll:

I'd forget the haynes manual, and setting the gap between the crimp and the outer cable, because unless you remove the sump you have no way of knowing if the crimp was fitted in the correct position in the first place. Personally I'd move the outer cable upwards using the adjuster until it touches the crimp and then roadtest. Make fine adjustments from there. If there isn't a fitted crimp, just adjust the outer cable upwards one turn at a time while roadtesting. If the outer cable touches the crimp and the pressures are still too high, then cut the crimp off the cable.

 

[Fischer]

hi Harvey

Please excuse my poor English .. but what is a "crimp" .... :?: :?: 8) And sorry for my stupid questions ... :roll: :roll: :roll:

/ Fischer

 

[harveyp6]

Please excuse my poor English

Don't worry about it, your English is far better than my Danish...

.. but what is a "crimp" .... :?: :?: 8)

The crimp is the small aluminium collar that is clamped on to the inner cable. In the illustration you showed, the feeler guages are positioned on top of the outer cable, and below the crimp.

And sorry for my stupid questions ... :roll: :roll: :roll:

As has been said many times before, there are far more stupid answers than stupid questions....

 

[Fischer]

Hi

Just a IRL shoot of "cable thing "

Picture taken with Engine of ....no throttel etc ......

Fischer

 

[harveyp6]

Hi

Just a IRL shoot of "cable thing "

Picture taken with Engine of ....no throttel etc ......

Fischer

You're not going to be able to reduce the pressures any further unless you cut that crimp off. At the moment you raise the outer cable, but that just raises the crimp, so you get no improvement. You can see slack above the crimp, and that shouldn't be there.

 

[Fischer]

hi

When you say "cut of the crimble" ... do you mean grind it off with a file or ... :?: :?:

If I "cut " it won't I cut the as well :?:

/ Fischer

 

[rockdemon]

Yup - just make sure you dont cut the cable - they arent cheap and it's something that isnt broken at the moment....

 

[Fischer]

Thank very much for reply's ... I'll will sent an update on the gearbox act after " operation Crimble"....

I'll be very very careful ..... but I'll probably f... it up anyway ... ha ha

/ Fischer

 

[stina]

I held mine in the nose of a mole grip and filed a flat on it , then managed to twist it off . Not easy to get in there , very easy to touch a strand of cable an toast it !

 

[74westy]

I have an interest in this thread as well. Here is my situation:

* rebuilt BW35 now using Dexron ATF. I know lots of comments on this but I am assured this is OK as the friction materials, etc have been upgraded using Ford items.
* completely rebushed rear suspension using rubber bushes.
* engine and gearbox mounts replaced.
* propeller shaft U-joints and sliding joint are tight and greased.
* drive shaft U-joints appear to be tight, no discernible slop here.
* new EP90 oil in differential.
* with handbrake on and footbrake on I have no clunking when moving from N-D or N-R.

What I have is a nasty clunk when downshifting 2-1 usually when going slow and coming off the throttle. I have followed the thread above and started to adjust the kickdown cable. I have gone 2 turns so far. The shifting seems better but not cured.

My question is how far can i go with this adjustment and what would be the effect if I go too far. Also what is the relationship between the kickdown cable and the hydraulic pressure?

Craig

 

[harveyp6]

* rebuilt BW35 now using Dexron ATF. I know lots of comments on this but I am assured this is OK as the friction materials, etc have been upgraded using Ford items.

The problem is that the slip that Dexron introduces causes extra heat which means the box ends up running overheated, plus any slip will introduce wear, which is the last thing you want bearing in mind how marginal the BW35 clutch packs are behind the V8.

* completely rebushed rear suspension using rubber bushes.
* engine and gearbox mounts replaced.
* propeller shaft U-joints and sliding joint are tight and greased.
* drive shaft U-joints appear to be tight, no discernible slop here.
* new EP90 oil in differential.
* with handbrake on and footbrake on I have no clunking when moving from N-D or N-R.

If all that is the case then everything sounds as though it is as it should be. What about going from R-D and D-R though?

What I have is a nasty clunk when downshifting 2-1 usually when going slow and coming off the throttle. I have followed the thread above and started to adjust the kickdown cable. I have gone 2 turns so far. The shifting seems better but not cured.

My question is how far can i go with this adjustment and what would be the effect if I go too far. Also what is the relationship between the kickdown cable and the hydraulic pressure?

The clonk on the 2-1 downshift on a closed throttle indicates that the line pressure is too high. That can be the cable adjustment, or the idle speed too high.
If you back the cable off too far then the idle speed line pressure won't reduce any further, but as the throttle is opened the line pressure will always lag behind the pressure that it should be for any given throttle opening. Take that to the extreme and eventually you'll lose the kickdown function, plus you'll run the risk of the clutches slipping because there isn't enough pressure to keep them clamped together at wide throttle openings, which is going to be exacerbated by the fact that you're running it on Dexron.

I'd be inclined to adjust the cable further, but if the inner cable has a crimp fitted, once the outer cable comes in contact with the crimp you won't get any further improvement unless you remove the crimp.

 

[rockdemon]

Is this a uk car or are you elsewhere? I only ask because Ron has mentioned upgraded parts in rebuilt australian boxes?


Rich