I'm rebuilding the hydraulic steering clutch control unit on our 4R D6 (4R1143). Back in 2007, King of Obsolete ran a thread on the process but it's unclear on thread size and type for the tool used to pull the oil seal retainers. Before I start chopping and grinding and welding, can anyone confirm the size and type of thread on the retainer?

The Service Manual calls for Cat tool 8B2893.

I would also appreciate any advice or warnings on rebuilding this unit anyone can offer... I mean, beyond leaving it alone, keeping it full of oil, and hoping for the best...

Thank you!

Drill out the seal retainer pins only.

Thank you, OM.

Regarding the seal retainer pins, neither the Service Manual nor the Servicemen's Reference manual call for drilling out that pin. Would there be a difference between a 4R D6 and a 9U D6?

That's one of Cat's secrets that they didn't tell you about. Did you locate the pins? Pins are shown in the parts diagram. Only two pins are shown but I believe there are four in total.
Go ahead and try pulling the seal retainers without drilling. If there is to much resistance you know what needs to be done. The retainers are aluminum so don't get carried away with the puller.
Would appreciate any corrections to the procedure.

Yes I see the pins. I was hoping to avoid that.

I'll let you know how it goes.

Thanks for the help.

Got this in my file but I'm not confident in the info.
Hopefully you will be able to verify.

Do you recommend using a replacement pin (assuming I can get one) or would you tap and use a bolt?

Threading for bolt or set screw has been the typical replacement.

OM, your information was all correct. Drilled out the pin, made the tool, and was able to pull both seal retainers. Took a 2 foot section of oilfield pipe as a cheater, but they did come out.



Any recommendations on getting the seals out without buggering the aluminum retainer would be greatly appreciated.



Thanks for your help!

Slide hammer with sheet metal screw into the seal. The type used for old time auto body work.
Where did the pin intersect the retainer? I don't see any visible signs in your picture.