I just had my transmission rebuilt by a local guy who is very good with rebuilding transmissions- he's done our powerglides, TH350's, and 700R4's for years, he also does racing transmissions. The results he reported are alarming however, regarding this TH400. So far as I know, with only 132k on the car when I bought it, there have been no alterations to the drivetrain. He says that almost every gear was pretty much fried and needed replacement- he went with solid aluminum pieces instead of the stock multi part steel ones. Also, he doesn't know how 3rd could even work it was so bad, and 2nd was pretty bad also. From driving it, I usually had no issues with 1st and 3rd, but barely had 2nd. He also says that- because I requested it- B&M shift kits, etc are crap and are meant only for racing. So I have a shift kit, I think it's from ATP Automotive, just that it's superior. He did a lot of work to the transmission to get it in condition again. Here's a list on the receipt of what he replaced/repaired:
Clutches, Steel S?, Gaskets, Seals- mod?, Sealing Ring, Bands, Bushings, apply Pistons (3), Accumulator Piston, P-Planes (2), Pump body & gears. Accessories applied: VB assy, SK-1. He also rebuilt the converter to 2500 stall speed for me. Final cost 1512.50.

What concerned him and me is this, with the supposedly stock dip stick tube and dip stick- identical in both jags I have- the end of the dip stick could not possibly be positioned where it will 'dip' into the transmission fluid, to the contrary it would slide along the bottom of the pan and have to turn to slide to the driver side of the pan. I haven't reinstalled it yet because I need to solve this issue. Test seating I won't do for fear of damaging something, but holding the dip stick to the side of the tube where it would seat the end of the dipstick would extend past the end of the pan, allowing for bends and everything, meaning the dipstick would be laying flat if you are lucky, most likely in a random position where it cannot possibly read fluid levels.

So, the above is alarming, but I found the solution or at least the answer. It's a 2 piece dipstick tube, the upper half is attached somewhere I can't see, but it seats in the lower half which is flared for the purpose. I must theorize that previous owners had not been good with keeping the fluid levels up in the transmission causing the damage seen by my transmission guy. Regardless, with this scare regarding the burnt out transmission, I'm going to test fit everything before I lift the transmission in, to verify proper depth. DO NOT want to burn up this transmission.

So, any advice from more experienced owners? I wanted to make sure the above information was available, since searching the forums did not produce any of this information regarding the dip stick tube.

For those who want to know who my transmission guy is: Dirty Dan's Tranz in Tukwila, Washington.

 

Interesting about the two-piece tube. After all these years I never noticed that!

If I understand you correctly you're thinking that the upper piece has gone missing? And, thus, the overall length of the tube is now way too short and that's way the dipstick itself slides along the bottom of the pan?

As for your trans overhaul it sounds like your guy covered all the bases. As good as they are, the old 400s can and do fail.....often expensively if you don't catch the impending doom early enough.

Cheers
DD

 

Welcome to the forums Micklex,

I've moved your post from General Tech Help to XJS forum as a more appropriate location.

Graham

 

Thanks for putting this in the correct location. I didn't realize it was 2 piece until after I got the transmission back and my dad mentioned issues with the dipstick length. I started comparing between my 2 jags, then crawled underneath the '87 since the transmission was out and found it. The upper half starts slightly higher than the tunnel, so it's not very obvious, plus several wires and other stuff is hanging there obscuring it.

Regarding that paragraph describing issues with length, that is what I was concerned and researching about, because it didn't really match my experience when putting fluid in the transmission. This sounds like I'm describing something entirely different- and more personal....

 

probably a stupid question but the TH400 you refer to is that the TH400 found in General Motors Cars in the late 60's? a modified bell housing for the Jaguars?

 

Yes. It's a unique case, but the workings are the same as GM cars.

 

so the internals are the same only the case is modified for the Jaguar motor?

 

A lot of European manufacturers have used General Motors transmissions. Most notably Rolls Royce. The later electronic overdrive four speed Turbo Hydro was also used by Jaguar in the XJS. The Turbo 400 was used in Corvettes and all the classic GM muscle cars.

 

Yes. Speedo transducer mount might be different too, but basically the internals are GM.