I need help trying to identify my transmission. Did GM make a th400 with tailshaft mounted parking brake? I have read the only true way to tell is to tear apart and check for straight cut gears. however I cant find if tailshaft mounted ebrake came only on th475?
FI code is supposed to be a 475 from a school bus or motor home ch***is, according to the Ron Sessions book.
yeah, I was told it was a perhaps a motorhome piece. I'm not sure weather to try and use it with a slip yoke from dennys or try to trade out with a th350/400. trying to keep it on the cheap$$$ thanks for looking into FI code for me! I have still yet to see a tailshaft with 4 bolt holes like mine that is on a TH400. It appears to me that could be an easy way to identify TH475...( although not all TH475 had the tailshaft brake)
This info may be completely incorrect but that tail shaft housing looks like one for a 4WD. The flange and bolt holes are so it can be connected to a transfer case.
I believe it is the Motorhome/Commercial unit and is configured for the trans mounted parking brake. Some years ago I had an RV with big block Chevy/400 (475) trans and the brake mounted thereon. Ray
As you know, that is set up for the bolt-on yoke, rather than the slip yoke. You do need the special yoke to convert to slip style. Can't help on the parking brake, but being from a bus/MH ch***is it makes sense that is what the four holes are for.
this is what I think will work http://www.dennysdriveshaft.com/p69...sion_slip_yoke_1310_series_32_spline_wth.html I also read (somewhere) you can use bolt on yoke application on trans side, and slip yoke on the pinion end? However, I haven't seen pinion slip design or such a part available to purchase?
The slip yoke is in the driveshaft. Look at 4x4 front driveshaft for examples. Fixed yoke on both ends, but the driveshaft itself has the sliding section. Usually the male part points to where the power is going. I think that slip yoke you put link to is the right one you need for this application, but check some dimensions to make sure.
Yes, that extension housing was used with a drum type parking brake. The straight cut gears are stronger, but are supposed to be noisier. The cases are also thicker in the bell-housing area. One of the old, dual range, cast iron Hydros I had years ago had come out of a BIG truck behind a Chevrolet V-8. It had the parking, drum brake mechanism on it also. It was a trans I picked up for free to use for parts. I am Butch/56sedandelivery.
That's a 475. I am pretty sure you can just ignore the flange and bolt on a yoke. Yup. I think most did not. Your average large truck/bus/motor home would not do good things to a parking pawl. Not a huge problem, so long as there is a real working parking brake somewhere else on the vehicle.
A lot of people like the drum brake when they convert to rear disc brakes and don't like the h***le of the small internal drums or the clutter of e-brake cables. Another use would be older MOPARs that had the drum on the trans and lose the parking brake when the swap drivelines. Somebody wants that trans so shop around.
The OEM trans mounted parking brake on the RV I mentioned in an earlier post was designed to apply automatically when the vehicle was shut off. I think a very strong spring applied the brake and was released by some device when the vehicle was put in drive. There was a procedure in the owner's manual for releasing the brake if the automatic release failed. I never had it happen in the time I owned the rig, but reading about dealing with that possibility made me very glad I didn't have to do it. Many/most/all medium duty trucks, especially GM, had trans mounted, manually applied, mechanical parking brakes. I would think that may be a more desirable brake to use, but it is rather large in diameter for the average street rod. Probably the same is true of the OEM automatically applied unit. Ray
Yes all 475 trans have a park pawl. This is just a park brake installed on the trans. It was used in medium duty truck applications.. The internals are just like a TH 400 trans
I have a th400 in my 51 F1 I used the bolt on yoke. I chucked it up in my lathe and cut a seat for a disc type freeze plug, works great. All of the slip type yokes I found were too long they would bottom out in the tail housing.
Then what explains all of the step vans and box trucks I drove that had the correct shape pan for a TH400 or 475, that did not even have a P position on the shifter?
Also keep an eye open for the deeper oil pan - at the very least snag that and the oil pickup. Should you come across one, there was also a switch-pitch TH400 in the BOP pattern in the late 60's (mostly found in Buicks if I remember right) that makes for a nice performance/highway cruising addition.
good news! I have linkage with functional park I will most likely order slip yoke and use the TH475... Trans looked super clean as well
I knew you would find park mechanism, the only automatic that doesn't have a park that I am aware of is an Allison, and only then in medium duty applications. Those for light pickups have a park mechnism
I imagine this has a 6 bolt torque converter attachment to the flex plate. The are a couple of different ways around the bolt on VS slip yoke issue you're going to face. A couple have already been mentioned. When I replaced the TH350 in my DD truck with a TH400 that had a bolr on yoke originally, I used a long slip yoke on the 2 piece driveshaft to make up for the small difference between the TH350 with the TH400; the TH350 was actually a bit longer with the 9 inch extension housing. I am Butch/56sedandelivery.
If I use this slip yoke from dennys, what do I do with the bearing in the tailshaft? I also see dennys is out of stock of the yoke I was looking at http://www.dennysdriveshaft.com/p69...sion_slip_yoke_1310_series_32_spline_wth.html
Try E-Bay for the slip yoke. I honestly have't seen the rollerized bearing in place of a bushing, but I don't see how it really could be any different dimensionally. Do you have the "original" yoke to measure? I am Butch/56sedandelivery.
no, I don't have the original... I did quick search on ebay, didn't see anything-I will keep looking though
Hey did you end up using the slip yoke or how did you go about doing this? i’ve got myself the same transmission and want to put it behind my 454 but having issues with this whole drive shaft and slip yoke thing just want to know if that dennys slip yoke actually worked.
How does a slip yoke work with a ball bearing? The yoke would slide in and out steel to steel on the bearing designed for spin only. Also where does the lip seal go?
The Jalopy Journal
