Hi I am new to the forum so forgive me if I get it wrong. BW8 auto problems

Forgive me if I go the wrong way about posting on here. Its my first time.
I am having problems with my borg warner type 8 gearbox on my Daimler DS420 Limousine. I know the same box is fitted to some e types so hopefully you can assist.
The box was removed to replace oil seal on pump behind the torque converter due to a massive leak. All sorted and now leak free. However the car changes from 1st to 2nd perfectly with hardly a trace however I am reaching 60+ mph at 2500rpm and it is not going to 3rd. It has the correct spec oil to the correct level. Only things I am unsure of and cannot find information on are kickdown cable settings and correct settings for brake band adjusting.
At present the cable on back of engine is pulled out at idle and pushes in with full throttle.
If anyone can assist with correct set up it would be greatly appreciated.
Kindest Regards Alex

2500RPM @ 60mph is actually quite low, and means you must be in 3rd

a BW8 will start in 2nd gear if D2 is engaged.

It will start in 1st if D1 or L is engaged

( so dont bother ever using D2)

What ratio diff do you have ?

This info is based upon 420G

To be honest I dont know?
All I know is that before the car changed up very smoothly all the way to 70mph with hardly any throttle and now after refitting the box the car seems to be running at far higher revs and it really does not feel right. Before when setting off in D it would change up at about 10 to 12mph and again at 30 to 40 with minimal throttle. Now its doing the first change as I would expect it to (smoother than before). But is not changing up after that. I dont know the exact speed I am doing as I am waiting for a new angle drive for speedo!!!
The way I understand the box is there are 2 break bands for 2 gears and top gear is achieved directly via the torque converter.
So was wondering if either brake bands needed adjustment or if kickdown cable is set up wrong and holding it in 2nd.
The only things that may have changed are the new oil or the cable may have been put back on incorrectly.

the cable is very sensitive to adjustment indeed, as per the Service Manual, and may not be adjusted,having said that, it still should change to 3rd with RPM 2780 at 60mph with 3.54 diff

You would need to verify what speed and RPM your vehicle changes gear using Mobile Phone App to verify speed, and the Factory Service Manual gives very accurate details on speed, RPM & throttle openings, so that you can check exactly

do you have a copy ?

The speeds at which you describe it previously changing sound about right

Thank you for your reply.
Unfortunately I have struggled to find any literature at all on correct set up.
I would like to correctly check the break bands and ensure kickdown is set correctly but have nothing to refer to.
Any information at all would be a huge help.
I will take the car out again on my day off tomorrow and use the satnav on my phone as a speedo to give a clearer picture of what its doing.

I have a large amount of information on BW8 trans., but have a question for you

Will your vehicle “kickdown” a gear, if the throttle is pressed to the floor (WOT)?

Mine will never do this, despite working perfectly in every other way,

I have had it, and other BW8 apart, spoke to a very experienced auto tran shop owner about this recently, he says it is a known issue with BW8

dont know of any internal mechanical issue that would cause 3rd to not engage, but no other fault

BW8 change is determined by internal pressure, which is controlled externally by one thing only…the throttle wire.

The pressure can be measured via port…low pressure cause soft/flared changes…high pressure, harsh change…a turn of the cable adjuster = 9psi

Hi Tony, thank you for your reply, there is no real change when I kick down. Gear change is very soft. Suspect pressure may be low. If you shorten the kickdown cable at rear of engine where it is linked to throttle will that increase pressure.
Cheers Alex

Do you have a Service Manual?

If not, at least get a electronic MKX/420G manual, as nearly all service parts are the same.

Does your car have Column shift D2/D1/L…as I mentioned, it only uses 2 gears in D2

Hi, yes it is column shift P,R,N,D2,D1,L.
Unfortunately I do not have a pressure gauge but will order one today. As a trial and error approach I turned the clevis out half turn at a time and after 1 full turn there is a noticeable improvement.
However I have now noticed that when the car is warm, setting off from a stand still at junctions it does give a slight graunch as if it is slipping slightly on the drive.
With the sat nav in the car I realized that I was driving quite a bit faster than I previously thought. 2300rpm at 60mph seems good.
Thank you for the information you have provided me. It has been most helpful and I certainly seem to be heading in the right direction.
I will perform a more precise set up once I have a pressure gauge.

The BW8 has an odd size pressure port, I will post the size later if I can find it.

I ordered that brass port, 300psi gauge and 6ft hydraulic hose and made my own

note…the port can be in 2 different places on a BW8…the one shown in the FSM…OR, on the other side of trans!

If your pressure is too low, the trans will flair on change, if too high, very snappy.
There is a fairly wide range of settings it will work ok

I tried mine over the complete range of settings while investigating the non-kickdown situation

Thats great thank you

1/8-27 pipe thread; male, with barb fitting, (to suit either 5/16 or 3/8" hose, depends on what hose size you use)

Thank you very much Tony you have been a great help.
Do you know what the brake band settings are? May as well check there right while im on with it.
Cheers Alex

the rear band is adjusted externally to the case.

On my vehicle this is done from inside the car, remove the console tunnel, and a plug in the body

imo you need a Service Manual if you own one of these vehicles, even if it is worked upon by a mechanic. Although I do own paper copies, the electronic version is very cheap and practical.

Google/Ebay “Jaguar MKX Service manual”

Thanks again, your a star.