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Removing 885 transmission

Posted: Mon Jun 17, 2019 6:23 pm
by ScottUSA
1976 DB885 leaking oil between the trans and diff. Ample silicone suggests someone has been in there before. This repair will be undertaken this fall unless the leak get too much worse. Along with the leak repair is a worn shift rail socket for 1st/rev that needs to be replaced. Read through the factory R&R transmission section. Can the rear tires be left on so the rear housing can be rolled back or must it be supported by a lift? Are there any areas in the hydraulic pump, pto, differential or transmission I should be sure look inspect while it's apart?

Re: Removing 885 transmission

Posted: Mon Jun 17, 2019 8:52 pm
by DB780
Yes, you can just roll the back end and gearbox away and out of the gearbox casing. The front half is supported on a jack and axle stands. There is a threaded hole in the gearbox casting that an eyebolt is fitted into and the backend rolled back and supported safely. The hydraulic suction pipe need to be removed. The PTO or carden shaft can be removed but it is not essential although it doe make re-assembly easier. David Brown recommended a hard setting gasket replacer for the back axle to gearbox join rather than a silicone one.

Re: Removing 885 transmission

Posted: Mon Jun 17, 2019 9:31 pm
by ScottUSA
The transmission can be left attached to the back end as it is rolled away from the transmission housing/gearbox casing? Am I understanding you correctly? The threaded hole, is it a dedicated hole for this purpose or one of the trans cover bolt holes? I'll look for it next time the tractor is used.

Hard setting gasket replacer; Permatex Aviation gasket maker has been around for decades in the U.S. but you may not recognize that product. Yamalube Yamabond is another semi drying gasket maker and possibly one with universal appeal? It's the one I am likely to use.

Thanks for the responce.

Re: Removing 885 transmission

Posted: Mon Jun 17, 2019 9:52 pm
by DB780
Yes, it is an hole for that purpose and the transmission goes back with the axle.

Re: Removing 885 transmission

Posted: Tue Jun 18, 2019 7:01 am
by cobbadog
I like and use that Permatex Aviation gasket sealer and it works a treat. Been available here in Oz for many years and prior to it being called Permatex it was also named Rolls Royce Aviation gasket cement. If it is not the same product it fooled me, same smell, consistency, colour and bottle, different name.

Re: Removing 885 transmission

Posted: Tue Jun 18, 2019 8:47 am
by ollek
Many paper gaskets in later tractors wore substituted by Loctite 504 Gasket Eliminator at the David Brown assembly line. This product was also recommended to be used is places where the loading on bolts is high. This flange seal makes the seam stronger as well as working as a sealant. The use of Loctite 504 instead of the paper gasket, or any other products, between the rear axle and the gear box frame is the solution recommended by David Brown.